View Full Version : SECA KITS Diy
Colin Wonfor
03-06-2015, 08:26
The new SECA KIT for the DIY is sounding very nice, PCB's for the Amp and the Dynamic PSU are now available.
I had Sam build them and he has now soldering or building experience.
http://i1148.photobucket.com/albums/o580/colinwonfor1/TEST%20BEFORE%20CLEAN_zpst9exkkj5.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/PSU%201_zps9ndmjryt.jpg
Colin Wonfor
03-06-2015, 08:55
Just for interest here is a 4 layer PCB for a Bass Guitar Amp I am making it took a few weeks to design the PCB and the maths for the filters etc was fun.
http://i1148.photobucket.com/albums/o580/colinwonfor1/Main%20PCB%20Both%20sides_zpsytpqmopb.jpg
Ali Tait
03-06-2015, 10:09
What power do you get from these Colin?
Colin Wonfor
03-06-2015, 10:33
What power do you get from these Colin?
From the SECA 20W from the Guitar Amp 1KW
With larger heatsink into 4 ohms 42W SECA
With PSU and SECA 25W 8 ohms 35W 4 ohms
Col
Ali Tait
03-06-2015, 10:37
Ok thanks.
Colin Wonfor
03-06-2015, 10:50
Ok thanks.
You are welcome.
Col
Which Transistors does the amp use? How would this compare to the JLH 10w ClassA? How much are the boards and how much would it cost to put an amp together inc PS?
Sorry for all the Q's.
awkwardbydesign
03-06-2015, 11:17
Which Transistors does the amp use? How would this compare to the JLH 10w ClassA? How much are the boards and how much would it cost to put an amp together inc PS?
Sorry for all the Q's.
Ditto.
More questions, sorry....
It looks like one board per channel for the amp. Is this true for the PS also?
From the photo it's a PP design, I assume it's not SE.
Input sensitivity?
Colin Wonfor
03-06-2015, 12:51
Which Transistors does the amp use? How would this compare to the JLH 10w ClassA? How much are the boards and how much would it cost to put an amp together inc PS?
Sorry for all the Q's.
OK I will try and paste here the BOM it is for one PCB.
15W Basic SECA PCB 27th Aug 2014
Type CCT REF Marked Value TOTAL REQUIRED Value Power/Volts Package FEC Unit Cost Tot Cost
Resistors R1,R10,R13 27R 3 27R 0.5W LEADED 9340343 0.01 0.04
Resistors R2, 560R 1 560R 0.5W LEADED 9340726 0.03 0.03
Resistors R3 47R 1 56R 0.5W LEADED 9340769 0.03 0.03
Resistors R4 4K7 1 4K7 0.5W LEADED 9340629 0.03 0.03
Resistors R5,R6 5K6 2 5K6 0.5W LEADED 9340734 0.03 0.06
Resistors R7,R18,R19 10K 3 10K 0.5W LEADED 9339787 0.03 0.09
Resistors R8,R15,R16 22K 3 22K 0.5W LEADED 9340211 0.03 0.09
Resistors R9,R14 1K 2 1K 0.5W LEADED 9339779 0.03 0.06
Resistors R11,R12 0.1R 2 0.1R 3W LEADED 1903849 0.13 0.25
Resistors R17 1K5 1 1K5 3W LEADED 1738681 0.11 0.11
Capacitors C1,C2,C3 100uF 3 100uF 35V 8mm LEADED 1818602 0.10 0.30
Capacitors C4,C8 1 10nF 2 10nF 50V 2.5mm LEADED 2332955 0.09 0.19
Capacitors C5 10uF 1 10uF 25V 5mm LEADED 2068976 0.01 0.01
Capacitors C6 220pF 1 220pF 50V NPO 2.5mm LEADED 9411755 0.03 0.03
Capacitors C7 47pF 1 47pF 50V NPO 2.5mm LEADED 2112854 0.03 0.03
Capacitors C10,C11 33,000uF 2 33,000uF 35V SNAPIN 6.21 12.42
IC, U1 AD820 1 INA122 Fit into socket DIL08 4.03 4.03
Transistors Q1 1 IRFP4410ZPBF TO247 TO247 1602246 1.53 1.53
Transistors Q2 1 BD140 TO126 1574351 0.45 0.45
Transistors Q3 1 BD139 TO126 1825611 0.38 0.38
Transistors Q4,Q5,Q6,Q7,Q8 5 BC337 TO92 TO92 1574379 0.10 0.49 NOTE MPSA42 ARE BETTER BUT FITT 180deg TO SILK
Transistors Q9 1 TIP142 TO247 TO247 9294287 0.83 0.83
Diodes D3 15V ZENER 1 1N5245B DO35 2148627 0.04 0.04 FITTED ON U1 PIN 7 = K. PIN 4 = A
Diodes D4 1 LED GREEN 3mm 2112096 0.11 0.11 USED AS REF VOLTAGE ONLY
Diodes D5,D6,D7,D8 6AMPS 200V 4 6A20G R6 1863166 0.20 0.82
FUSE HOLDER F2,F3,F1 3 20mm 20mm 2461158 0.61 1.83
FUSE F1 1 5A CERAMIC FB 20mm 1354547 0.46 0.46
FUSE F2,F3, 2 6.3A SLOW BLOW 20mm 1360819 0.23 0.46
CONNECTOR J2 LOW VAC POWER IN 1 4 WAY 5.0mm 3882172 0.30 0.30
INPUT PHONO INPUT 1 PHONO 1217028 1.08 1.08 CAN BE HARD WIRED SO THIS PART NOT REQUIRED
PRESETS IQ , CURRENT ADJUST 1 10k 0.33 0.33
PRESETS DC DC OFFSET ADJUST 1 1K 0.33 0.33
TO247 Thermal Pads 2 Ceramic 1577101 0.82 1.64
Transformer 225VA 1 15-0-15 9532811 31.67 31.67 USE WITHOUT PSU PCB
Heat Sink 0.5C/W OR BETTER 1 4621906 23.67 23.67
Thermal compound 1 2103717 8.90 8.90 PER TUBE
I hope this helps
The JLH from memory is fitted with DC blocking cap and it bandwidth and speed are much slower, nice design for the time and limit components like Neol Keywoods was.
Colin Wonfor
03-06-2015, 12:58
Hi Clive,
Sorry mate it is a SECA a DC coupled SECA, 1 amp pcb/channel or 1 amp pcb + 1 psu pcb/channel.
Not P-P like other amps, but clive the clue is in the title.
SECA KITS Diy
The 2 power device you see are 1 FET this is the Amp and 1 Darlington this is the constant current source for the FET, not PP, it was all on Hi-fi Answer a few days ago. So you can catch up there Clive.
Is that OK?
Col
Cant see the screen printing from the pic, the TIP are the output transistors?
Thanks Colin, even though I have Class A SE solidstate and valve amps I wasn't familiar with the term SECA.
Colin Wonfor
03-06-2015, 13:13
Cant see the screen printing from the pic, the TIP are the output transistors?
The TIP142 Darlington is the constant current for the FET N Channel.
http://i1148.photobucket.com/albums/o580/colinwonfor1/15W%20SECA%20PCB%20COMP_zpsurbxfxye.jpg
Colin Wonfor
03-06-2015, 13:14
Is the valve OTL or transistor output?? and what valves?
Col
Is the valve OTL or transistor output?? and what valves?
Col
It's a 300B TX coupled.
The solidstate amp has a cap at the input so not DC coupled.
Colin Wonfor
03-06-2015, 13:19
It's a 300B TX coupled.
The solidstate amp has a cap at the input so not DC coupled.
Nice , the solid state output is the DC coupled ? is it a Nelson beasty? or JLH or your own? tell us more.
Nice , the solid state output is the DC coupled ? is it a Nelson beasty? or JLH or your own? tell us more.
Unusually for me it's not one I built. It's a Valvet E1r. Valvet is a one man-band from Germany, Knut Cornills is designer. Here's the inside, the Mcap is the input DC blocker:
http://i43.photobucket.com/albums/e359/cmeakins/ValvetinsideII003.jpg (http://s43.photobucket.com/user/cmeakins/media/ValvetinsideII003.jpg.html)
Colin Wonfor
03-06-2015, 13:33
Unusually for me it's not one I built. It's a Valvet E1r. Valvet is a one man-band from Germany, Knut Cornills is designer. Here's the inside, the Mcap is the input DC blocker:
http://i43.photobucket.com/albums/e359/cmeakins/ValvetinsideII003.jpg (http://s43.photobucket.com/user/cmeakins/media/ValvetinsideII003.jpg.html)
Has it got a op-amp class B type input, and complementary fet output?
How may Watts is it and how big is the heatsink can,t see from PIC
Has it got a op-amp class B type input, and complementary fet output?
How may Watts is it and how big is the heatsink can,t see from PIC
I can't comment on the opamp, I just don't know.
Size: 120 x 60 x 350 (WxHxD in mm)
10W into 8R, 18W in 4 R and 32W into 2R. 20,000uF filtering, 80VA PTX. It's a bipolar output transistor. Quiescent current is floating so it gets away with a smaller heatsink than otherwise.
http://i43.photobucket.com/albums/e359/cmeakins/Vfull_zpsd9bbaf44.jpg (http://s43.photobucket.com/user/cmeakins/media/Vfull_zpsd9bbaf44.jpg.html)
Colin Wonfor
03-06-2015, 13:51
Nice:)
awkwardbydesign
03-06-2015, 14:54
I just joined the Hi Fi Answers site, and had a look for the SECA info. I saw the two articles about the case and the build. Are there more?
Colin Wonfor
03-06-2015, 19:39
I just joined the Hi Fi Answers site, and had a look for the SECA info. I saw the two articles about the case and the build. Are there more?
Yes lots but busy doing bigger things and I am caught up with new Bass Guitar Amp.
So I am tiding up instructions test sheet etc then PSU and more and more and then BOM etc.
Colin Wonfor
08-06-2015, 20:22
The PCB each are £20.00 you will need 2 Amp PCB ie. £40.00 AND PLEASE ALLOW FOR £5.00 p&p
2 PSU at £20.00 each parts will be better if you got them yourself,
Parts are standard Maplin, RS, FEC, Radio Shack etc.
http://i1148.photobucket.com/albums/o580/colinwonfor1/Amp%20A%20Class%20Kit%20SECA%20%20bridge_zps8ywhx6 r9.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/Amp%20A%20Class%20Kit%20SECA%20_zpsxitiugcj.jpg
PLEASE NOTE THE ZENER DIODE D3 IS NOT MOUNTED ON THE PCB THE CATHODE IS SOLDERED DIRECTLY PIN 7 OF U1 AND THE ANODE IS SOLDERED TO PIN 4 OF U1
http://i1148.photobucket.com/albums/o580/colinwonfor1/15W%20SECA%20PCB%20COMP_zpswxww7iub.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/Basic%20SECA%20double%20sided%20track%202oZ%20Cu_z ps7opmegje.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/SECA%20KIT%20BOM%20JUNE%202015_zpsidrh1w9s.jpg
Looks very good Colin..Might fancy doing that myself.
RobsterD
09-06-2015, 17:04
Hi Colin ,
I'm definately be interested how do want paying etc ?
Regards
Rob
Colin Wonfor
10-06-2015, 19:21
Hi Rob sent PM and now e-mail, best Col
Colin Wonfor
12-06-2015, 13:35
Now working on a super version will be available in a few month after I have tried to kill it. It will out perform the Iridium but it will not be so cheap to make as the baby version now available, parts are silly prices (sorry). It will use the same PSU but will also self generate on the Amp PCB a 2 x Vc drive this will push the dynamics higher and increase the bandwidth to a silly 1MHz, we do filter the input to stop you local Taxi service from wrecking the sound but the amp damping factor will also improve.
And from those out there who commented on the less expensive Amp thanks for your input on construction it has all been implemented. See Pic.
http://i1148.photobucket.com/albums/o580/colinwonfor1/seca%2015w-30w%20pcb%20vi%20iss1_zpstlqwdo4l.png
Sovereign
12-06-2015, 14:03
Fantastic !:stalks:
Colin Wonfor
13-06-2015, 08:35
PSU to Amp connection.
http://i1148.photobucket.com/albums/o580/colinwonfor1/PCB%20CONNECTIONS_zpss7e1rloc.jpg
The new SECA KIT for the DIY is sounding very nice, PCB's for the Amp and the Dynamic PSU are now available.
I had Sam build them and he has now soldering or building experience.
http://i1148.photobucket.com/albums/o580/colinwonfor1/TEST%20BEFORE%20CLEAN_zpst9exkkj5.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/PSU%201_zps9ndmjryt.jpg
Is the top photograph the SECA and the lower photo the Dynamic PSU? Would it be possible to provide a PCB for the latter that does not use surface mount components?
You say 20W is available from the SECA, yet the PCB has "10W Class A SECA" printed on it. What is the maximum voltage swing at the output terminals? (I use Quad 57 ESLs, which can be damaged if they receive a signal > 20V rms).
Sorry to ask so many questions Colin, but I would be interested in building a pair of these amps.
Thanks
Barry
Colin Wonfor
13-06-2015, 12:41
Hi Barry,
"Is the top photograph the SECA and the lower photo the Dynamic PSU? Would it be possible to provide a PCB for the latter that does not use surface mount components?
You say 20W is available from the SECA, yet the PCB has "10W Class A SECA" printed on it. What is the maximum voltage swing at the output terminals? (I use Quad 57 ESLs, which can be damaged if they receive a signal > 20V rms).
Sorry to ask so many questions Colin, but I would be interested in building a pair of these amps.
Thanks
Barry"
The top is the Amp.
Bottom the PSU.
PSU was not going to be sold with this for the DIY but assembled but James and Paul convinced me 1206 SMD resistors could be place by hand by anybody and Sam above has proved this.
10W on the PCB is the min power out.
The Amp PCB will run at lower enough voltage to keep below 20V i.e. 20V RMS is 50W this amp will be OK if heatsink dissipation does not exceed 100W
So you well loved Quad will be OK as the PCB is ideally suited to run less than 30WRMS.
Barry and anybody you are all welcome to ask questions so please do, try to avoid techy stuff.
Best Col
Sovereign
13-06-2015, 15:26
The SMD parts arnt so bad as long as you have a steady hand and a bit of patience, sometimes solder paint can be helpful.
Colin Wonfor
14-06-2015, 20:31
This is the power ON/OFF circuit Sam used in his Kit, which was made in a Maplin £39.00 PC chassis. Press "RESET" to turn ON and the PC "ON" button to turn OFF. And a LED to indicates ON, Standby power was less than 1W.
http://i1148.photobucket.com/albums/o580/colinwonfor1/POWER%20SSR%20SW_zpsnd7ikx59.jpg
Colin Wonfor
16-06-2015, 15:37
Steve on Sunday was forced to listen to this he he.:eyebrows:
"DIY SECA Kit
I recently had the opportunity to hear the best sounding 'computer case' I've come across..!
I'm not a reviewer so bear with me if my analogies are a bit wayward, but I'm trying to find ways to express a 'sense' through words. I should add that the time spent was more of a listen than a test or review and connected components were only a 10+ year old DVD player as source (!), bog standard IEC power cables and cheap mid-sized stand-mount speakers. I'll surmise my thoughts based on existing experience (neither vast nor exotic) - They're musical, fast, detailed, pure and textured.
From cold, the opening track through the SECAs began with a thrum across acoustic guitar that was open with an in-the-room'ness quality…
With acoustic, ambient/electronic and voice the overriding sense is that the SECAs are VERY open, detailed and light of touch, music seems almost as if carried on air.
The sound is just 'there' and 'pure' rather than other amps that seem to almost push music down a tube, constraining and colouring it. I think the SECAs may be what some would call 'natural' sounding (ie. they don't really add anything).
Sound no longer came from (within) the speakers but more like a bloom of sound that surrounded or escaped their confines and filled the space around with an effortless delivery."
Thanks Steve.
Sovereign
16-06-2015, 17:10
Great, I haven't been able to start my build yet as I'm stil making my 40 watter
A heads up to those building the tracking power-supply.
Firstly on my BOM there are two R13s, the correct value for R13 is 10k, the other R13 is in fact R6 which is 3K6.
Secondly I managed to put DS1 and DS2 in the wrong way, they are described as Connectors but are Schokkty Diodes, they have a line on them which denotes Cathode and on the board there is a little white dot which denotes the cathode. I missed both of them and had to desolder these smds (or as Apple predictive text put it - sods).
And another thing - the first thing you should solder on the board (in my opinion) is Q9 - a tiny smd transistor which I found hard to see the legs never mind solder them.
Hopefully that is all the smds sorted for this year.
Sovereign
16-06-2015, 22:58
The joyful pains of the novice DIY 'er
I remember when I first started making stuff which was only the beginning of last year, and the frustrations I used to face, but then some take to it like a duck to water.
I always tried to rush things. If you have patience and a steady hand you will be fine.
Colin Wonfor
17-06-2015, 15:10
A heads up to those building the tracking power-supply.
Firstly on my BOM there are two R13s, the correct value for R13 is 10k, the other R13 is in fact R6 which is 3K6.
Secondly I managed to put DS1 and DS2 in the wrong way, they are described as Connectors but are Schokkty Diodes, they have a line on them which denotes Cathode and on the board there is a little white dot which denotes the cathode. I missed both of them and had to desolder these smds (or as Apple predictive text put it - sods).
And another thing - the first thing you should solder on the board (in my opinion) is Q9 - a tiny smd transistor which I found hard to see the legs never mind solder them.
Hopefully that is all the smds sorted for this year.
Thank you I am sitting to close and I have the added advantage of knowing what bit is what.
Sorry Alan, BOM fixed.
Type Ref Value Power/Volts Package FEC
Resistors, R1 10R 3W LEADED 2117958
Resistors, R2 10R 3W LEADED 2117958
Resistors, R3 240R 250mW 1206 1100174
Resistors, R5 240R 250mW 1206 1100174
Resistors, R9 100R 250mW 1206 2413803
Resistors, R11 1K 250mW 1206 1632522
Resistors, R12 1K 250mW 1206 1632522
Resistors, R14 100R 250mW 1206 2413803
Resistors, R15 470R 250mW 1206 1799533
Resistors, R19 10K 250mW 1206 2131811
Resistors, R20 100R 250mW 1206 2413803
Resistors, R4 3K6 250mW 1206 1646735
Resistors, R6 3K6 250mW 1206 1646735
Resistors, R7 0R1 3W LEADED 1903849
Resistors, R8 0R1 3W LEADED 1903849
Resistors, R10 10K 250mW 1206 2131811
Resistors, R13 10K 250mW 1206 2131811
Resistors, R23 10K 250mW 1206 2131811
Resistors, R25 10K 250mW 1206 2131811
Resistors, R16 470R 250mW 1206 1799533
Resistors, R18 470R 250mW 1206 1799533
Resistors, R17 1K 250mW 1206 1632522
Resistors, R21 1K 250mW 1206 1632522
Resistors, R24 1K 250mW 1206 1632522
Resistors, R22 100R 250mW 1206 2413803
Capacitors, C1 33,000uF 35V SNAPIN 2357396
Capacitors, C2 33,000uF 35V SNAPIN 2357396
Capacitors, C3 10,000uF 50V SNAPIN 2284050
Capacitors, C4 10,000uF 50V SNAPIN 2284050
Capacitors, C5 10uF 50V 5mm 2069014
Capacitors, C6 10uF 50V 5mm 2069014
Capacitors, C7 470uF 35V 10mm 2069004
Capacitors, C8 100nF 100V X7R 1206 2341508
Capacitors, C9 100uF 50V 8mm 1167965
Integrated Circuits, U1 LM337 TO220 1211104
Integrated Circuits, U2 LM317AT TO220 1214459
Transistors, Q1 MJW21196 TO247 1700966
Transistors, Q2 MJW1302A TO247 1705822
Transistors, Q3 ZTX753 E-LINE 9525637
Transistors, Q6 ZTX753 E-LINE 9525637
Transistors, Q4 ZTX653 E-LINE 9525580
Transistors, Q5 ZTX653 E-LINE 9525580
Transistors, Q7 ZTX653 E-LINE 9525580
Transistors, Q8 MPSA42 TO92 1017719
Transistors, Q9 BC846 SOT23 1081229
Diodes, D1 6A20G DOP7 1863166
Diodes, D2 6A20G DOP7 1863166
Diodes, D3 6A20G DOP7 1863166
Diodes, D4 6A20G DOP7 1863166
Diodes, D5 1N4004 DO41 2306351
Diodes, D6 1N4004 DO41 2306351
Diodes, D7 1N4004 DO41 2306351
CONNECTORS CN1 AC1 2WAY 3.96mm 1756761
CONNECTORS CN2 AC1 2WAY 3.96mm 1756761
CONNECTORS CN3 GND 2WAY 3.96mm 1756761
CONNECTORS SPK 2WAY 3.96mm 1756761
Diodes, DS1 10BQ100 2120143
Diodes, DS2 10BQ100 2120143
FUSES F1 6.3 CERAMIC SLOW BLOW 20mm 1360819
FUSES F2 6.3 CERAMIC SLOW BLOW 20mm 1360819
FUSE HOLDER F1 20mm 146123
FUSE HOLDER F2 20mm 146123
CONNECTORS DC OUT J1 4WAY 5.0mm 3882172
CONNECTORS SPK SENSE J2 4WAY 5.0mm 3882172
SMALL CONNECTORS RLY ON 2WAY 2.5mm 9979611
ZENER ZD1 BZX79C4V7 DO35 9844597
RELAY 12V SPCO RL1 G2R-1A4 24DC 2065712
TO247 Thermal Pads 2 Ceramic 1577101
225VA 18-0-18V 9532838
I also cheat I read the circuit not the BOM, I must try both for checking.
The joyful pains of the novice DIY 'er
I remember when I first started making stuff which was only the beginning of last year, and the frustrations I used to face, but then some take to it like a duck to water.
I always tried to rush things. If you have patience and a steady hand you will be fine.
James,
I am at the other end of the spectrum, retired, late sixties with a large number of electronics builds behind me. Hand/eye coordination is not brilliant and is tested by these smds.
Power supply boards finished, today I should get the amp boards built.
James,
I am at the other end of the spectrum, retired, late sixties with a large number of electronics builds behind me. Hand/eye coordination is not brilliant and is tested by these smds.
Power supply boards finished, today I should get the amp boards built.
Hi Alan,
After the joys of the SMDs the Amplifier boards will be a breeze. I went the other way - did the amplifier boards first to get my soldering eye in, and then started on the PSU boards. I'm still awaiting some parts for them, so have had to pause for a few days though....
Colin Wonfor
19-06-2015, 08:13
The great thing about SMD is the size when you drop them on the floor I can't see them.
Sovereign
19-06-2015, 23:26
I rarely listen to classical music, but tonight I dug out a classical remaster of some of the greatest Queen songs. I honestly didn't know how low my amp goes, there was a huge ground floor apartment that I didn't even know was there, and it reached these depths effortlessly.
These Wonfor Class A amps ooze scale and size of sound window, one year on and my amp still takes me by surprise and impresses me.
Colin Wonfor
20-06-2015, 07:22
Hi James, Paul's SECA looks amazing.
http://i1148.photobucket.com/albums/o580/colinwonfor1/P6190055_zpseekrn7os.jpg
Classical music now ABBA will be upset :eyebrows:
Sovereign
02-07-2015, 16:04
Here are my completed circuit boards being mounted on the heat sinks. I expected to have finished the amp by now but time is quite tight at the moment.
I am hoping............ to have it up and running tomorrow..:piano:
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_4203.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_4203.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_4199.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_4199.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1378.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1378.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1381.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1381.jpg.html)
The baby SECA looks like a good starter diy amp. I haven't build anything since the DDDAC. I would need a relatively small enclosure though, could anyone comment if the enclosure in the link below would be man enough with respect to heatsink?
http://www.ebay.co.uk/itm/2612-Full-aluminum-power-amplifier-enclosure-case-DIY-chassis-BOX-/121171238287?pt=LH_DefaultDomain_3&hash=item1c365e5d8f
Many thanks, Si
The baby SECA looks like a good starter diy amp. I haven't build anything since the DDDAC. I would need a relatively small enclosure though, could anyone comment if the enclosure in the link below would be man enough with respect to heatsink?
http://www.ebay.co.uk/itm/2612-Full-aluminum-power-amplifier-enclosure-case-DIY-chassis-BOX-/121171238287?pt=LH_DefaultDomain_3&hash=item1c365e5d8f
Many thanks, Si
Si,
You need at least .4deg Centigrade per watt for each heatsink. Judging by the size it should be close, best to question the seller. Would you be going for the Amp board only or Amp plus PSU board. In the latter case there is more heat to be dissipated.
Important! Before I make any more comments on the A-Class kit it should be noted that I am a good friend of Colin the designer and I may be a little biased.
So I have built both the Amp and Tracking Power Supply boards and they have been mounted on their heatsinks but are not yet in their cases which I have to make.
I disabled the Thump Buster circuit removing diode D7 - I have not experienced any switch on problems.
The amps are set to have a bias of 1.5 amps by adjusting the voltage across R11 or R12(the .1R resistor) to be 150 mV. The temperature is settling at about 50 degrees C, the ambient room temp is about 26-27 C.
So how does it sound - in a nutshell, bloody marvellous! OK so some context is required. My system has changed recently and now is Windows 7 / XXHE, Uptone Regen USB device, iFi iDSD micro, Kondo M77 clone, PassDIY F5 mono blocks into Infinity RS3a speakers. The latter are not particularly easy to drive but the F5s manage very well.
The SECA amps (I tend to build mono blocks) sound as good as the F5s in all areas and better them in the bass where the SECA seems to go lower and is tighter, better defined. Low level detail abounds throughout the spectrum and to say that it is easy to listen to is a bit of an understatement.
Anybody hearing my system may think it is a little 'slippers and pipe' but it suits me.
Once I have made the cases and installed the amps I will take some photos - just want to make sure the mains police don't visit me! At that point people would be welcome to come to Farham and have a listen.
Just to reiterate my first point I cannot pretend to be un-biased about the kit.
looks the business James. alas no point in me building as it wouldn't work lol.
nice wee write up Alan. glad colin's amp is sounding so good
Any idea what the mains power consumption is for the SECA?
Thanks sondale, I'll drop them a line, as they're from china I'm not sure if or how quick I'll get a reply. I was planning on amp and psu boards. Nice write up by the way. Out if interest what heatsinks and case are you using/planning on using.
Cheers, Si
Thanks sondale, I'll drop them a line, as they're from china I'm not sure if or how quick I'll get a reply. I was planning on amp and psu boards. Nice write up by the way. Out if interest what heatsinks and case are you using/planning on using.
Cheers, Si
I am using the same heatsinks as Sovereign, one per channel, they are available from RS. For the case I have had some sheet ally cut to size which I need to drill and tap, it would have been cheaper to get one of the cases from Ebay, there do seem to quite a few suitable ones.
The baby SECA looks like a good starter diy amp. I haven't build anything since the DDDAC. I would need a relatively small enclosure though, could anyone comment if the enclosure in the link below would be man enough with respect to heatsink?
http://www.ebay.co.uk/itm/2612-Full-aluminum-power-amplifier-enclosure-case-DIY-chassis-BOX-/121171238287?pt=LH_DefaultDomain_3&hash=item1c365e5d8f
Many thanks, Si
Should be ok if run @ low bias, but check bits will fit.
This was the case I was going to get, but wanted heatinks internal, and not quite big enough for a stereo amp.
Important! Before I make any more comments on the A-Class kit it should be noted that I am a good friend of Colin the designer and I may be a little biased.
So I have built both the Amp and Tracking Power Supply boards and they have been mounted on their heatsinks but are not yet in their cases which I have to make.
I disabled the Thump Buster circuit removing diode D7 - I have not experienced any switch on problems.
The amps are set to have a bias of 1.5 amps by adjusting the voltage across R11 or R12(the .1R resistor) to be 150 mV. The temperature is settling at about 50 degrees C, the ambient room temp is about 26-27 C.
So how does it sound - in a nutshell, bloody marvellous! OK so some context is required. My system has changed recently and now is Windows 7 / XXHE, Uptone Regen USB device, iFi iDSD micro, Kondo M77 clone, PassDIY F5 mono blocks into Infinity RS3a speakers. The latter are not particularly easy to drive but the F5s manage very well.
The SECA amps (I tend to build mono blocks) sound as good as the F5s in all areas and better them in the bass where the SECA seems to go lower and is tighter, better defined. Low level detail abounds throughout the spectrum and to say that it is easy to listen to is a bit of an understatement.
Anybody hearing my system may think it is a little 'slippers and pipe' but it suits me.
Once I have made the cases and installed the amps I will take some photos - just want to make sure the mains police don't visit me! At that point people would be welcome to come to Farham and have a listen.
Just to reiterate my first point I cannot pretend to be un-biased about the kit.
So you like it then Alan ? :)
I'm really pleased with my little stereo amp..
I've just started building the boards for a monoblock build, with the PSU this time.
Colin Wonfor
04-07-2015, 20:14
Any idea what the mains power consumption is for the SECA?
Hi Shane,
Depending on bias and thus heatsink from 140W/ch to 200W/ch.
Colin
Sovereign
04-07-2015, 22:39
Important! Before I make any more comments on the A-Class kit it should be noted that I am a good friend of Colin the designer and I may be a little biased.
So I have built both the Amp and Tracking Power Supply boards and they have been mounted on their heatsinks but are not yet in their cases which I have to make.
I disabled the Thump Buster circuit removing diode D7 - I have not experienced any switch on problems.
The amps are set to have a bias of 1.5 amps by adjusting the voltage across R11 or R12(the .1R resistor) to be 150 mV. The temperature is settling at about 50 degrees C, the ambient room temp is about 26-27 C.
So how does it sound - in a nutshell, bloody marvellous! OK so some context is required. My system has changed recently and now is Windows 7 / XXHE, Uptone Regen USB device, iFi iDSD micro, Kondo M77 clone, PassDIY F5 mono blocks into Infinity RS3a speakers. The latter are not particularly easy to drive but the F5s manage very well.
The SECA amps (I tend to build mono blocks) sound as good as the F5s in all areas and better them in the bass where the SECA seems to go lower and is tighter, better defined. Low level detail abounds throughout the spectrum and to say that it is easy to listen to is a bit of an understatement.
Anybody hearing my system may think it is a little 'slippers and pipe' but it suits me.
Once I have made the cases and installed the amps I will take some photos - just want to make sure the mains police don't visit me! At that point people would be welcome to come to Farham and have a listen.
Just to reiterate my first point I cannot pretend to be un-biased about the kit.
Glad your happy. When I first heard my Iridium the first thing I noticed was also much deeper bass, but it wasn't simply hearing the next bass note down, it was the fact that the floor of the music has fallen away and there is a whole basement apartment beneath you, and you are now hearing the deepest notes on the recording , and effortlessly.
Thanks for the replies all. Could anyone let me know the dimensions of the amp and psu pcbs please as i'm trying to make a decision on an enclosure.
Many thanks, Si
PS are the pcbs ordered directly from Colin or is there a webshop?
Both 121.5mm square.
Order directly from Colin.
Thanks again quickie. Good job i checked, i need a slightly higher enclosure than the one i was looking at.
This is the case I used.
http://www.ebay.co.uk/itm/DYT-1-Black-panel-Aluminum-Enclosure-case-Power-amp-box-DIY-PSU-chassis-sn-/141349561938?pt=LH_DefaultDomain_3&hash=item20e9172652
Available with a silver front panel if you prefer.
With the following heatsinks. One for each channel cut in half.
http://cpc.farnell.com/abl-heatsinks/350ab2500b/heat-sink-0-42-c-w/dp/SC10888
I've had some heatsinks custom made with a slightly better spec, but even ordering 12 they are over £25 each, with four needed for a stereo amp.
Colin Wonfor
06-07-2015, 11:04
Batch 2 will be here by Thursday.
I have made this batch with a higher density Cu so we can run the driver if required at a high bias this will increase the Bandwidth to over 1MHz.
The circuit has been designed to run current in A Class in the driver stage with a standing current of 10mA but now it can be pushed to 30mA see table.
R set...........I Drive Current....P dis W..............HS Type
68..................9.68.............. 0.174
56.................10.77..............0.193
51.................11.76..............0.212....... .....Heatsinked.....PCB
47.................12.77..............0.230....... .....Heatsinked.....PCB
39.................15.38..............0.277....... .....Heatsinked.....PCB
33.................18.18..............0.327....... .....Heatsinked......Al
27.................22.22..............0.400....... .....Heatsinked......Al
22.................27.27..............0.491....... .....Heatsinked......Al
18.................33.33..............0.600....... .....Heatsinked......Al
Sovereign
06-07-2015, 22:06
Case is ready, all connectors are in, Just got to bolt on the feet and put a nice finish on the middle section of the front. Not 100% sure about the exposed heatsinks, it will start to look the business once I start stacking three amps on top of each other.
Just need to see when I can get me boards from Colin.
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1384.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1384.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1386.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1386.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1387.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1387.jpg.html)
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1388.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1388.jpg.html)
And another thing - the first thing you should solder on the board (in my opinion) is Q9 - a tiny smd transistor which I found hard to see the legs never mind solder them.
Thanks for the tip Alan.
Some bits arrived from Farnell this afternoon, so I made a start on the PSU boards.
That transistor is tiny ! the 1206 resistors arn't too bad though.
Colin Wonfor
09-07-2015, 16:20
Note the suspended fan no noise.
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_165623635_HDR_zpsqlqctzsg.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_165609523_HDR_zpsx0wickwm.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_165551370_HDR_zpslyayirf7.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_165542912_HDR_zpsyyivza8z.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_162213325_HDR_zpsnljpb2jg.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/IMG_20150709_140220945_HDR_zpsi1u48hkr.jpg
walpurgis
09-07-2015, 16:36
I like that layout. Reminds me of a BMW bike engine! :)
Wow! that's a beast. I was planning on fitting the boards into one of these:
http://www.modu.it/pesantedeng.html I've bought the 3U sized unit, 400mm deep with the 10mm aluminium front panel. The final capacitors for the boards arrived today so if I can find some time then I'll get the whole unit finished in the next few days. Looks like I'll have to be cautious on the heat output though.
Colin Wonfor
09-07-2015, 20:43
Wow! that's a beast. I was planning on fitting the boards into one of these:
http://www.modu.it/pesantedeng.html I've bought the 3U sized unit, 400mm deep with the 10mm aluminium front panel. The final capacitors for the boards arrived today so if I can find some time then I'll get the whole unit finished in the next few days. Looks like I'll have to be cautious on the heat output though.
That will look like something nice, I tell you what I have your, you have mine OK, what NO, :lol:
A tip to keep heat sink a safe temp, if you use a small size Preset PR2 you will find to hole left, one pin goes to the negative power rail and the other goes to R18.
Now buy two of these from Farnell not cheap but worth it.
http://uk.farnell.com/epcos/b57703m0103g000/thermistor-ntc-10k-2-rad/dp/1200456
http://uk.farnell.com/productimages/standard/en_GB/1200456-40.jpg
Fit this into the spare pins as mentioned above, and mount on heatsink, or M3 stud on the darlington Q9, This PR2 should be set fully Anti=Clockwise before power up,
Now adjust the current using PR2 and read voltmeter at 100mV/Amp the voltage can be read across R11, monitor temperature in room ideally 20C and wait a short time until heatsink reaches 50C, if it creeps above to say 60C re adjust PR2 until it settles. The reading shout be between 170mV and 250mV this will depend on your heatsink. In hot weather now the amp will back of the current and on those cold winter nights the amp will produce more warmth with the music, as it try to maintain 50C on the heatsink, if the heatsink is enclosed and no hands can be burnt set to 62C for more current.
Best Col
Colin Wonfor
16-07-2015, 07:17
For those with good eyes sight and a steady hand have a go at this.
http://www.hifianswers.com/2015/07/mc-head-amp-design-that-was-first-used-in-the-magnum-amps/
Colin Wonfor
20-07-2015, 21:05
Oh yes the improved mods use the same PCB but with a few bit cost lots more I am sorry to say but well worth it. I have one now with the upgraded bits, Sam is standard and Paul I suspect will do what I have done.
The FET has gone to a monster and the Darlington has been replaced with a FET, the same one as the drive, it 1.5mR RdsON and only 350A but the SOA is much nicer tons of room for higher current IQ.
The FET driver stage IQ has also gone up but now the BD139/140 have to be fitted with heats sinks.
It sung beautifully before but now it is shear angel music, with the harp top and the bass of a cannon.
The BOM will reflect the upgrade but you may need a mortgage. Sorry lads.
Colin Wonfor
21-07-2015, 20:18
http://i1148.photobucket.com/albums/o580/colinwonfor1/SECA%20FET%20KIT_zps9ahjrifk.jpg
SECA Kit can be improved to provide deeper BASS and more power only few more watts, Will lose the 2V saturation on the original darlington constant current to a few millivolts. The heatsinks now under dynamic power out will run cooler so we can push the current up so those nasty 4R speakers will behave,
The PCB stay the same so place your orders now, new stock in.
Sovereign
21-07-2015, 23:45
Sounds good mate!
Colin Wonfor
26-07-2015, 18:13
http://theartofsound.net/forum/showthread.php?39718-The-Brief-History-of-my-life-with-SECA-designs
Had one of this version running at Alan,s today it sounds fantastic on Infinity's.
Colin Wonfor
06-08-2015, 13:19
I am about to start sell the PCB made up with the super fet version 2 with all PCB components and the ceramic washers, so all you will need is a transformer, chassis, and a pair of large heat sink.
Each Amp PCB will be about £100.00 each +P&P
No soldering for You at all to the PCB
Sovereign
08-08-2015, 21:29
Colin remember all the boards I'm after. Don't go selling out whilst I'm away on holiday
Colin Wonfor
21-08-2015, 16:18
Thank guys for all the best wishes on my Old age Birthday, yes James I am over 21 ish he he :lolsign:
I can vouch for the SQ on the Infinity's as I there was there on Tuesday.
Colin Wonfor
25-08-2015, 06:47
Preparing components.
Bend the resistor wire ends this is the 1K5 3W.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtp1/t31.0-8/s960x960/11890038_1478654225786270_4071029997338841013_o.jp g
100mR or 0.1R 3W
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/s960x960/11850457_1478654235786269_739858690638573254_o.jpg
The smaller resistors.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/11914745_1478654682452891_3108507451857610804_o.jp g
The resistors mounted.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/11921833_1478654945786198_6771269008407786584_o.jp g
Capacitor mounted. C5
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/11900141_1478654885786204_5841691101555606528_o.jp g
The current control preset near the AD820 op-amp.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/11894668_1478655042452855_9041551011599083601_o.jp g
Fuse holder and 18-0, 0-18V power input for the transformer.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/11934544_1478655049119521_8578849270998709021_o.jp g
Bending and mounting the 6Amp diodes in the bridge rectifier.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xft1/t31.0-8/11878982_1478655122452847_7161035371911787638_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtp1/t31.0-8/11885715_1478655119119514_9169269936428180405_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/11875021_1478655145786178_3335527983140687944_o.jp g
Mounting the Green Led that is used to generate the ref voltage for the Current control. Note the long leg is near the hole it will be soldered into this is the Anode.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtf1/t31.0-8/11865003_1478655245786168_1602194775666699998_o.jp g
Led with the two 10nF caps behind.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/s960x960/11872276_1478655259119500_4485002825149468433_o.jp g
One of the two 33,000uF bulk capacitors note the stripe in the case it is the Negative terminal alway check these or big bang will be louder than the music.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/11873403_1478655492452810_3677479701915953082_n.jp g?oh=d061079de997c01f198c460a5ac43cde&oe=563E0C2C
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xat1/t31.0-8/s2048x2048/11230745_1478654505786242_603666771704667049_o.jpg
Mounting the Op-Amp AD820.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/11011287_1478654539119572_8111096207473233696_o.jp g
The BC337 transistor and the DC offset preset.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xaf1/v/t1.0-9/10341695_1478654555786237_1300350322714787204_n.jp g?oh=6ced84a19f536d16e33aa5c64cd81c41&oe=563D298A
The drive transistors BD139 and the BD140, see there orientation and the BD140 is on the right. Solder them closed as the PCB acts as a small heatsink. Also mount the BC337 close but not tight to the PCB. See above.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/11924367_1478654805786212_6409623771591340121_o.jp g
Here is the PCB,sI did for Ben, (thanks for the order Ben )
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/11894552_1478655252452834_8173960998400096901_o.jp g
On set up insure the IQ preset is Anticlockwise and the DC offset is centre.
PCB 1 , 5Hz - 100KHz Flat PCB 2, 5Hz - 100KHz Flat at full power (15W) in this case.
DC offset -3.2mV 0.3mV
I/P Z 13.5K 13.5K
Damping 1150 1128 with a 250VA transformer tag on.
Phase angle 20Hz - 20KHz -,+ 3.0 deg both PCB,s
Also not the insulators under the MOS FETs a small amount of heatsink compound only OK "U" yes you now who.
These ready made PCB a pair are £200.00. Please contact me cj14wonfor@gmail.com AND NOT TELLURIUM Q email address PLEASE
Phase angle 20Hz - 20KHz -,+ 3.0 deg both PCB,s
Doesnt that suggest a varying group delay?
3 deg at 20Hz = 4.2us
3 deg at 20k = 4.2ns
Colin Wonfor
02-09-2015, 09:47
At last people are having great success in making the kits with some lovely comments on the sound.
Thank you all for your support.
Thanks you
Sovereign
03-09-2015, 21:09
Colin your SECA amplifiers produce the sound I have been looking for for the last five years, thanks for making them so accessible
Colin Wonfor
16-09-2015, 18:10
This photo is Paul Quicks lovely work on a Mono SECA and a twin SECA. Fantastic workmanship, and the variations of styles are great.
http://i27.photobucket.com/albums/c165/quickiers/P9160224_zpskjgkgmr3.jpg
walpurgis
16-09-2015, 18:36
They look great Colin! :)
Colin Wonfor
19-09-2015, 08:12
I have costed up the build for the PSU PCB's at £95.00 each + PP the max current is 6A with current fold back, this will charge the caps much slower and reduce the thump on most amps have in this style of design, the soft anti thump relay is now removed reducing costs and sounding better.
Colin Wonfor
01-10-2015, 07:35
Simon, completed Amp on Audiochews.
http://i651.photobucket.com/albums/uu237/undarra2000/IMG_2867_zpsj1rwu9ya.jpg
Hopefully there should be enough room to fit the PSU boards too :)
Colin Wonfor
02-10-2015, 17:41
Here are Dave's Amps and they are Mono.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xta1/t31.0-8/r270/11224233_1500087423642950_8172274026225518673_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/12079996_1500087486976277_905403972138304071_o.jpg
Colin Wonfor
02-10-2015, 17:58
Now you buy the PCB ready made or for you to build from One4Audio.
Ready made Amp £100.00 each
Ready made PSU £95.00 each
Blank unpopulated Amp PCB £20.00 each
Blank unpopulated PSU PCB £20.00 each
http://i1148.photobucket.com/albums/o580/colinwonfor1/Chris%20PCBs_zpsiwzuqlld.jpg
Some constructions are already done so see them on:-
http://www.audiochews.com/discussion/1608/building-colin-s-seca-kit/p1
Colin Wonfor
05-10-2015, 06:04
PSU
Zener under AD820 and PSU updated BOM
Zener@ 12V 1.0 - 1.3W under the AD820 on the bottom of PCB note the polarity on Amp PCB. Cathode on pin 7 and the Anode on pin 4 ,
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/12074783_1500955100222849_3288795018772833097_n.jp g?oh=0a1da5703910306e2fa095650525471d&oe=56D0CE2D
PSU BOM
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xap1/v/t1.0-9/11224311_1500833620234997_2687095091725887120_n.jp g?oh=9a5fcbf1cef850ec3390c1312f49d665&oe=56A71A0F
Colin Wonfor
12-10-2015, 15:26
See Ben's results on.
http://www.audiochews.com/discussion/1666/ben-s-wonfor-seca-build-ready-populated-boards#latest
http://i1003.photobucket.com/albums/af151/docfoster/Amps_zpss5p6pqrs.png
There are some lovely builds of the Seca amps. Hopefully my build will turn out as good,the pcb's are nearly finished with just a couple of caps to solder in when they arrive.Next will be the chassis which I am reusing after stripping out the current amp boards.I will use the existing p/s to start with.
I have a couple of questions; the bias trimmer is set clockwise before start up? Also is the p/s left floating or is the ground connection connected to the chassis either directly or through an isolating network?
TIA Keith
Colin Wonfor
14-10-2015, 19:45
There are some lovely builds of the Seca amps. Hopefully my build will turn out as good,the pcb's are nearly finished with just a couple of caps to solder in when they arrive.Next will be the chassis which I am reusing after stripping out the current amp boards.I will use the existing p/s to start with.
I have a couple of questions; the bias trimmer is set clockwise before start up? Also is the p/s left floating or is the ground connection connected to the chassis either directly or through an isolating network?
TIA Keith
I have a couple of questions; the bias trimmer is set clockwise before start up? Fully Clockwise Yes
Also is the p/s left floating or is the ground connection connected to the chassis either directly or through an isolating network? I set them as isolated, and then had signal earth bach via the I.C. to the pre.
I have a couple of questions; the bias trimmer is set clockwise before start up? Fully Clockwise Yes
WARNING - IT SHOULD BE FULLY ANTI-CLOCKWISE, I checked with Colin and his original reply is incorrect.
The DC Offset should be set in the middle of the pots range.
Colin Wonfor
16-10-2015, 08:46
Sondale, you are right again, that's me looking from the solder side again sorry.
Thanks Alan. I must admit I was a little confused as some of the photo's have it in both positions.
Colin Wonfor
16-10-2015, 19:20
Sorry Marra I read the PCB from the back.
No harm done Col at least I hadn't turned on and fried anything.
I always use a light bulb tester on initial fire up so that would have prevented high current from damaging things.
Ali Tait
16-10-2015, 21:23
Always a good thing to do.
Sovereign
16-10-2015, 21:51
Ali, have you started your build yet ?
This is the chassis and p/s that I will be reusing
http://i867.photobucket.com/albums/ab236/Marra49_photos/GEDC1233_zpsdb97d8ad.jpg (http://s867.photobucket.com/user/Marra49_photos/media/GEDC1233_zpsdb97d8ad.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/005_zpsb9891163.jpg (http://s867.photobucket.com/user/Marra49_photos/media/005_zpsb9891163.jpg.html)
Sovereign
17-10-2015, 18:42
Chassis looks perfect
Ali Tait
17-10-2015, 18:51
Ali, have you started your build yet ?
No, haven't bought the pcb's yet. Haven't been well recently.
anthonyTD
18-10-2015, 09:39
Sorry to hear that Ali,
Hopefully your on the mend now.:)
Haven't been well recently.
Ali Tait
18-10-2015, 10:02
Cheers Anthony, yes getting better thanks.
anthonyTD
18-10-2015, 10:23
:)
Cheers Anthony, yes getting better thanks.
Canetoad
18-10-2015, 10:58
No, haven't bought the pcb's yet. Haven't been well recently.
Get well soon mate! :)
Ali Tait
18-10-2015, 11:00
Cheers Bernie. :-)
Colin Wonfor
22-10-2015, 14:55
This is one I made for Justin.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xlt1/t31.0-8/10256667_1507621792889513_7882504899814133932_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xap1/t31.0-8/11703469_1507621639556195_7888868428123651002_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xta1/t31.0-8/12140088_1507621559556203_6571197381649261128_o.jp g
PCB mounts on PCB to heatsink
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtp1/t31.0-8/12140861_1507621466222879_7466788459253645041_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/10988322_1507621489556210_2973500794692903938_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xta1/t31.0-8/11123985_1507621502889542_3961238315347149453_o.jp g
walpurgis
22-10-2015, 15:03
Looks great Colin! :)
Colin Wonfor
22-10-2015, 15:19
Sounds OK except I set the PSU's to turn OFF on clipping and it is far too quick so it going to be turn OFF. I miss the loud punch , it far too quick but it not bad at all I'll make another for sure.
Colin Wonfor
24-10-2015, 15:02
Soft Start PCB for SECA Kits is now available.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/12029607_1508451482806544_6351696004451842335_o.jp g
Colin Wonfor
24-10-2015, 16:24
Ready built or plain PCB?
Have to put a block diagram up and BOM plus circuit yet.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtf1/t31.0-8/10550027_1508473469471012_6407864222583365362_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xap1/t31.0-8/12185202_1508473459471013_2337061886979609944_o.jp g
Colin Wonfor
26-10-2015, 10:28
BOM for Sort Start..
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/12188987_1509088376076188_5038811148616401142_n.jp g?oh=56265780c248f0c09eb50bbb52bf1525&oe=56CC598A
Hi Colin
Thanks for the boom which will be most helpful and also to Keith for heads upping this interesting looking amp over on PFM.
Seems like the trade police :eyebrows: have been at work over there so I’ll continue the conversation here if that’s OK with you.
I’m interested in building the full amp as mono's ‘’when the birthday money tree is ripe’’ but would love to build one of your nice soft start boards for another amp to start with.
Just thought I’d shoom it past you.
Colin Wonfor
26-10-2015, 11:39
Hi Colin
Thanks for the boom which will be most helpful and also to Keith for heads upping this interesting looking amp over on PFM.
Seems like the trade police :eyebrows: have been at work over there so I’ll continue the conversation here if that’s OK with you.
I’m interested in building the full amp as mono's ‘’when the birthday money tree is ripe’’ but would love to build one of your nice soft start boards for another amp to start with.
Just thought I’d shoom it past you.
Please do but PM me here or there is best.
More info on Audiochews.
Now I go back work on the new Pre-Amp and Claymore having just had a Coffee and Kit-Kat Break.
I am enjoying a last my forced retirement still hate the bastards but who the hell cares.
Claymore:)
loved the last one
I'll sort out my order for the soft start pronto.
you have PM
Colin Wonfor
29-10-2015, 10:10
Just a note, please insure when you mount the LM337 and LM317 on your heatsink to use the insulating mounting kit correctly and check with meter that there are no short circuit to the heatsink from the Tab of these regulators, because it will blow fuses.
This check should also be done for all the Semiconductors (transistor and FET's)
The short circuit could be a cracked insulator or the TOP HAT that goes through the mounting hole on the LM317 or the LM337.
Do this check before you wire the PCB up to transformer and amp pcb.
If it happen after you checked it check again the first audible sign is a chattering relay. On the PSU board, this is normally a blown fuse.
Colin Wonfor
29-10-2015, 10:14
Some free software to convert your PC into a scope
And there is some signal generators also
http://download.cnet.com/s/oscilloscope/
http://download.cnet.com/s/signal-generators/
I have also had few good ones on Android's Software for a Huddle and Kindle HD thing.
They are not perfect but can be used to do fault finding.
I am experiencing problems having burnt out R11 and it would seem Q9:doh: I wondered is there a way of testing the mosfets in circuit?
Colin Wonfor
09-11-2015, 05:42
Marra,
Source to Drain will read s/c on a meter.
Col
After a self inflicted hiccup:doh: I am happy to say that things are back on track :)
The amp is now up and running and has been playing through the stunt speakers for a couple of hours. I will try with a better speaker tomorrow.
A couple of pics:-
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0599_zpszgdjtlfm.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0599_zpszgdjtlfm.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0600_zpstkal9ych.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0600_zpstkal9ych.jpg.html)
Colin Wonfor
09-11-2015, 19:54
Looking good
To improve the sound of the SECA I have removing C4 makes it sweet with guts.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtf1/v/t1.0-9/12193367_1514771615507864_3112802098070294551_n.jp g?oh=492c6b09be213c5a4a19d51a83156b98&oe=56B43A8C
Excellent stuff Keith.......
Nice one Col..........less is more :)
Colin Wonfor
10-11-2015, 08:29
Looking good, I would have just bypass a rectifier diode and left the fuses in, but what the heck it works, DC offset look good, at 1.5Amps nice.
Looking good, I would have just bypass a rectifier diode and left the fuses in, but what the heck it works, DC offset look good, at 1.5Amps nice.
Didn't think of that Col it would give some extra protection.
Colin Wonfor
10-11-2015, 13:21
It would but do use sand filled they sound better and only 16p each.
Like these are also very good.
http://cpc.farnell.com/siba/70-007-65-6-3a/fuse-20x5-ceramic-slow-blow-6/dp/FF02850
Colin Wonfor
11-11-2015, 06:15
Keith Use four feet not two silly. :)
The simplest solutions are the best:lol:
Thanks for the tip re removing C4 Col.
I removed them this afternoon and the sound has sweetened slightly and seems to have lost an edge to the sound that I was experiencing.
This little amp certainly can go loud can't it.
A couple of pics of the finished amp which is currently running at just below 2 amps.
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0606_zpsfqvxz8c1.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0606_zpsfqvxz8c1.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0605_zpspkutsuun.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0605_zpspkutsuun.jpg.html)
Colin Wonfor
13-11-2015, 10:56
That is looking good how is the sound? :)
Thank you Col.
Deep textured bass;very open mids and treble with a deep and wide soundstage; so pretty good:):)
Does the tracking p/s build further on this?
Colin Wonfor
13-11-2015, 13:43
Yes it does, the low level stuff becomes precise and indulging.:):sorry:
Colin Wonfor
13-11-2015, 15:13
Here is the information on the soft start PCB.
This is the BOM
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/12247149_1516227695362256_2858353521856656519_n.jp g?oh=43737d1687c316f6ef748e36c0d3e011&oe=56B034B0
These are the circuits.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xtl1/t31.0-8/12240950_1516227708695588_1156445386815875449_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpl1/t31.0-8/12240374_1516227738695585_7164971507253154855_o.jp g
Here is the PCB layout.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpt1/t31.0-8/12238134_1516227748695584_3626582753526105675_o.jp g
Here are two version the left is with spades and the right with leads and IEC connection.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xla1/t31.0-8/12241020_1516229288695430_1461835860555755000_o.jp g
Here is the spades and a EARTH TAG WHICH MUST BE CONNECTED TO CHASSIS
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xlf1/v/t1.0-9/12243238_1516229478695411_7838411513854016274_n.jp g?oh=bc6da9f432ccddddf5ab5a2e083d817d&oe=56BEFD27
What is the input sensitivity and gain of the One4 please.
Colin Wonfor
16-11-2015, 17:00
Hi 0.7V for 14W
Colin Wonfor
19-11-2015, 18:06
Soft Start Configuration
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfp1/t31.0-8/12240343_1518540235131002_6141415860880732848_o.jp g
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpl1/t31.0-8/12045384_1518540221797670_3875302107393835799_o.jp g
I have made a couple of changes to my build since my last post. The input electrolytic has been replaced with an off board mounted polypropylene and the input 22k resistor is now soldered directly on the phono socket. This is now starting to sound very good having had several hours of use.:):)
The tracking power supply will be added in the New Year.
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0607_zpsav7toz6n.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0607_zpsav7toz6n.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0609_zpsf18s2ijx.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0609_zpsf18s2ijx.jpg.html)
Colin Wonfor
21-11-2015, 17:49
Well done looking good, How is the bass?
Pretty good Col although it has to be said that the speakers that I am listening to the amp through do not go overly deep but they seem to be reaching lower than before.
I am enjoying what I hear though.
Very much looking forward to adding the p/s boards to the mix in the New Year.
Is there an alternative to the MJW1302A in the power supply? TIA
Colin Wonfor
24-11-2015, 14:20
Buy it from here
http://uk.farnell.com/on-semiconductor/mjw1302ag/bipolar-transistor-pnp-230v/dp/1705822?ost=MJW1302A&selectedCategoryId=
I'm a skinflint Col;) Don't like paying for stuff coming from the States.:eek:
Colin Wonfor
24-11-2015, 16:03
this one.
http://www.profusionplc.com/products/2SA1943
http://uk.farnell.com/on-semiconductor/njw0302g/transistor-pnp-250v-15a-to3p/dp/2101386
http://uk.farnell.com/toshiba/tta1943/transistor-audio-pnp-230v-15a/dp/1901958
http://uk.farnell.com/on-semiconductor/mjh11019g/darlington-trans-pnp-200v-15a/dp/2101381
Hi Colin,
I've just noticed that you don't have a dedicated sub-forum for your business, as all the other traders do... Small oversight, mate. Would you like one? :)
Marco.
Colin Wonfor
24-11-2015, 18:34
Hi Marco,
OK what is it ?
Col
You would be listed here, under 'O', and given your own room to ply your wares:
http://theartofsound.net/forum/forumdisplay.php?17-Trade-Impressions
Marco.
Colin Wonfor
25-11-2015, 19:36
Ha ha ha twit :lol::)
Lol... So you wanty a roomy like wot da others 'av, or wot? :D
Marco.
Colin Wonfor
26-11-2015, 08:00
Cor yer mate :eyebrows:
Colin Wonfor
26-11-2015, 09:18
It is a yes please.
Ok, I'll organise it, but make sure you use it!
Marco.
Ok, Colin, your sub-forum is now ready for use, see here: http://theartofsound.net/forum/forumdisplay.php?102-One4Audio
Do not leave the room lying empty, with the word 'Never' next to it, as that looks bad, and will result in the sub-forum being deleted after a period of time, if there is no activity.
Therefore, please open it, ASAP, by posting there and introducing your company and its products and services, and/or advertising your SECA KITS. In future, that's where all your stuff should go.
Cheers! :cool:
Marco.
Hi ALL
I've just completed my SECA mono builds over on PFM.
Anyone wanting to read through the thrills and spills, downs and ups of my build look here.:lol:
http://www.pinkfishmedia.net/forum/showthread.php?t=179305&page=8
it's just a rough and ready try out build but the sound I'm getting so far is superb.:)
great work Colin
great amps
Colin Wonfor
02-12-2015, 17:14
You did a good job there and thanks for the feedback. :)
Colin Wonfor
04-12-2015, 11:33
A few people/DIYer have been asking about the PSU Board well here goes.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xlf1/v/t1.0-9/12341462_1524239464561079_644880927634376402_n.jpg ?oh=d7c5e861f0e0e93d53d1af81ca0ae13d&oe=56D3CFEA
The Sliding or Dynamic PSU
As you can see the +V and –V regulator are based on the LM317 and LM337 chips, these are drive current gain stages and have a very simply current fold back current limit using 0.1R resistors to set this to about 6A.
This current limit allow the 10,000uF and the SECA’ s 33,000uF capacitors to charge much slower and this will increase their life and reduce the ON thump.
The basic just SECA board has a ripple voltage of about 500mV but with the PSU this is reduced to approx 5mV, this will show itself as more detail at low levels when using the PSU together with the SECA.
The losses across the FET are there because we have a Gate Source voltage of about 4 – 5V so the FET cannot drive to the +V rail, the Darlington in the original has a voltage across it of about 2V and thus it cannot swing to the –V. So to use the full range of the power/volts available we use the PSU board with all the advantages mention before. In version 2 with the 2 FET’s the –V is not such a problem as we only lose about 200mV max.
Now as the output approaches the max regulated +V or –V on peaks the PSU ref is also moved and as it approaches 10V peak the PSU output voltage changes and allow the FET/Darlington to get to the max voltage it can, this gives you more punch and dynamic, this will show up on deeper bass and fresh top end.
Hi Colin
Nearly ready to fire up the dynamic PSU’s and was starting to wonder what’s the best way to test before fitting to the SECA.
Any tips welcome:)
Colin Wonfor
09-12-2015, 08:01
Hi Stig,
Power up check output volts one will read -20V the other +20V DC.
Thanks Colin
I'll report back once I've hit the switch.:)
Colin Wonfor
15-12-2015, 13:03
For sale on Chew ready made.
http://www.audiochews.com/discussion/1735/seca-amplifier#latest
All up and running with the regulated supplies.
It would be good to have a chat around setting up the SECA at its optimum (sweet spot).
http://i1101.photobucket.com/albums/g433/shaun71/heatsink%20xl.jpg (http://s1101.photobucket.com/user/shaun71/media/heatsink%20xl.jpg.html)
The above chart shows (amongst other things) the heat sink specifications required for each operating point.
I managed to have a read of this last night and it seems that it has some other useful info on setting things up.
Just to be sure that I have grasped all of the info.
My speakers are PMCFB1+ which is stated as 93db W 8ohm and being transmission lines are a fairly flat load impedance wise.
So looking along the ‘’Optimum load’’ line and arriving at 8ohm I get
Current 2.5A
Max power OP 24.99W
Power dissipation 100
With the new heatsinks @0.18C/W
Temp above ambient 20deg
Looks like a good point to aim for.
I think that I’ll be putting the PSU on its own sink to use the main sink for music goodness only.
I have my 0.38C/W HS running @ 1.9A ATM (about 14W I think) and I’ve noticed that the sound has got better with each turn of the screw bias wise.
Adding the Regulated PSU has improved things also and is well worth the little extra effort involved:).
More detail, better focus, tighter bass (quite unlike most of the Class A that I've heard) are just a few of the highlights that I’ve noticed. Yes I’ve even had a few of those ‘’never heard that in the recording before’’ moments.
Oh have I mentioned that the SECA runs much more quietly with the PSU in place.
Anyhow Big boy Heatsinks and copper spreaders are in Santa's sack awaiting the long trip from grotto land.:eyebrows:
roll on Xmas
Nice work Colin:cool:
Colin Wonfor
19-12-2015, 17:07
Merry Xmas Stig and thanks for the info, the best sweet spot I found was 2.1A but the heatsink I had let me cook eggs and bacon hot.
Merry Xmas Stig and thanks for the info, the best sweet spot I found was 2.1A but the heatsink I had let me cook eggs and bacon hot.
2.1A should be more than fine with the new heatsinks.
I'll make sure that they are heated up before breakfast.
Merry Xmas
Sounds like the ideal New Years fodder.
I will have to increase the bias on mine.
Merry Christmas all.
I’ve found that the sound improved with each bias increase so far and now that Santa has delivered the new heatsinks and copper spreaders it’s useful to know where to aim bias wise.
When I added the PSU board with my bias set to 1.5A I found the sound had an increase in detail, tighter bass and a more panoramic view but seemed to lose a little tonal colour compared to the standard on board PSU. The PSU also seemed to reduce noise at the speaker, not that the standard SECA is noisy but the PSU helped push the noise down further.
No big deal on the tonal colour front as I’ve heard that before when swapping to a regulated supply.
But increasing the bias seemed to sort the tonal pallet out nicely.:)
I also found that the way I have my boards mounted to the sink made the heat distribution a little uneven but hopefully the 300 x 40 x 4mm copper bars will help that issue a little.
I have my SECA set to 1.9A ATM and the current sinks run warm but not hot enough to fail the PASS 5 second rule. With Santa’s bigger sinks in place it should run a little cooler.
The SECA are sounding superb here with great detail, convincing sound stage and super Bass.
IMHO, to my ears and my set up.
Looking forward to your thought when the PSU are added Keith.
and a HAPPY NEW YEAR:cool:
Colin Wonfor
28-12-2015, 09:13
Well done Stig, unfortunately I could take mine into hospital for Xmas and Boxing Day, but we had a lovely rendition from one of the Doctors and lovely treat for all of us sickies, to all the staff at Newham thanks guys.
And another thanks to all NHS workers.
especially those who worked over Xmas.:cool:
The SECA is really sounding superb.:)
Another big thank you to NHS workers nothing but praise for them. Along with my wife they brought me back to good health after undergoing heart surgery a few years back.
I think it's likely to be a couple of weeks before the p/s is up and running but your comments Shaun make me keen to get it done and have a listen.
How are you going to configure the boards on the new heatsinks? I'm thinking that I need to rearrange my layout as at the moment all the heat is at the rear of the sink; but at 1.7A you could sit on it all day as they don't get much above 40C.
I have been offered two transformers with 19-0-19 secondaries at a very good price. Is the extra volt one to many?
Happy New Year all:cool:
Colin Wonfor
29-12-2015, 07:13
Marra
Are you using 25V caps then NO
I bit to high, big bang after a while with black holes and supernovae.
Yes NHS Bristol did a great job on my ticker all new plastic valves and plumbing and a pet slug scare to boot.
Back to Newham again infection exploded. Lots and lots of pain and no bike rides for while.:violin:
No they are 35V caps so will be ok.
My current transformer despite being built to suit 240V mains and 18V secs still outputs close to 20V.Still within regulation specs.
Colin Wonfor
29-12-2015, 10:18
No problems , that would give you a max Transformer voltage of 24V-0 . 24V - 0 AC
How are you going to configure the boards on the new heatsinks? I'm thinking that I need to rearrange my layout as at the moment all the heat is at the rear of the sink; but at 1.7A you could sit on it all day as they don't get much above 40C.
Hi Keith
I’ve also noticed that the board mounting method I’ve used is less than optimum with most of the work being done at one end of the heat sink.
I’m going to use a 300 x 40 x 4mm copper heat spreader for better heat spread across the sink which hopefully will do the job. As you say the sink is not running George Forman :lol: hot but a more even spread across the sink can only be a good thing.
Those 19V trafos look fine and if they are a good price you’d be wise to grab them.
The PSU (to my ears) makes for a nice bump up in quality in all areas, tightening the sound and increasing clarity.
IMHO to my ears and in my set up.
One of the main advantages of ‘’relatively low power class A’’ is the ability to add regulation which becomes a little more impractical as the power goes up.
The SECA IMHO does a nice impression of A big class A amp in terms of timing, control and dynamics which all improve noticeably with the Reg in place.
And the imaging is just spot on.:eyebrows:
Hi Shaun;
Yes the transformers are to good a bargain to pass up:)
From where did you obtain your copper bar? I can't seem to find anything thicker than 3mm on the bay.
Colin Wonfor
29-12-2015, 14:51
Hi Marra,
Ask Quickie he also used copper bar
or use this http://uk.farnell.com/duratool/7097086/copper-flat-bar-25x6mm-pk4/dp/7097086
or maybe this http://uk.farnell.com/duratool/7097062/copper-flat-bar-25x3mm-pk4/dp/7097062 or has did use alminium
http://uk.farnell.com/duratool/7094620/aluminium-flat-bar-3-4x1-8-pk5/dp/7094620
Best Col
Had my two from here Keith
http://www.ebay.co.uk/itm/261951456353?_trksid=p2060353.m2749.l2649&var=560768346928&ssPageName=STRK%3AMEBIDX%3AIT
Thanks for the links Col and Shaun:thumbsup:
Copper bar is on order and the transformer will be collected next so time to get my finger out:eyebrows:
I should be ready to start the refit next week.
Now that all of the Xmas fun :lol: is out of the way.
I found some time to transfer the First SECA Mono to the new sink.
2.1A:eyebrows::eyebrows:
The copper spreader seems to be doing it's job with the head noticeably more even over the sink.
Running warm but not roasting and cooler than with the old sinks at 1.9A.:)
One down and one to go.
Tomorrow:cool:
Hope my fingers are up to another session:lol:
Happy New Year ALL
Colin Wonfor
01-01-2016, 20:32
How have you mounted the heat spreader to the top or the bottom ? the bottom is normally better.
Hi Colin
Spreader to the bottom seemed intuitively correct so I went with that.:)
Leaves the transformer secondary’s a little longer than I’d have liked but I’ve not found that to be an issue up to now.
I do have a cunning plan for that once my fingers have recovered from the poor workmanship that flows from them.:eyebrows::lol:
SECA Mono No 2 up and running @ 2.1A
A&E on full standby but not needed:lol::lol:
http://i1101.photobucket.com/albums/g433/shaun71/big%20seca.jpg (http://s1101.photobucket.com/user/shaun71/media/big%20seca.jpg.html)
Larger heatsink and copper spreader fitted. I also installed the BG –N IP Cap.
Looks like all systems go.:cool:
I've added a BA-3 FE Pre to my set up and together with the SECA it's sounding superb.
A nice pair:eyebrows:
We have music through the stunt speakers:D
Hopefully have a proper listen tomorrow.
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0624_zpsmxeevj89.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0624_zpsmxeevj89.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0623_zpslnitxqqx.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0623_zpslnitxqqx.jpg.html)
brian2957
13-01-2016, 15:38
I know nothing about electronics Keith but this looks the biz . Hope it sounds as good as it looks mate :)
there is also "the Real thing " :-)
http://www.diyaudio.com/forums/pass-labs/234355-guide-building-pass-f4-amplifier.html
I know nothing about electronics Keith but this looks the biz . Hope it sounds as good as it looks mate :)
Thanks Brian. I am pleased to say that the One4 amp sounds superb; I have a big grin on my face.
there is also "the Real thing " :-)
http://www.diyaudio.com/forums/pass-labs/234355-guide-building-pass-f4-amplifier.html
Care to elaborate.
there is also "the Real thing " :-)
http://www.diyaudio.com/forums/pass-labs/234355-guide-building-pass-f4-amplifier.html
yes show us your build. Or even the F6 will do if you don't have the F4.
Keith don't you have the F6 or was it the Aleph J or maybe the F5. I Know it as one of the three.
I've not tried the B4 yet but find the SIT darn interesting potential next build.
I've just had a play with the BA-3 FE as a pre running with 10db gain which sounds mighty fine to my ears and in my set up.
I ran an F5 for a couple of years then built an Aleph J which is imho a stunning little amp.An F4 followed but then I was a beta tester for the F6 which is still in use but not with the original boards and again imho another stunning little amp from Papa.
That is the thing with the diyaudio store boards for the First Watt range of amps which Nelson generously donates to the community after having done his commercial run is they are of a size and it is so easy to to swap out boards and try various amps. They all use the same power supply.
What resistor did you use for R13 to lower the gain in your BA3 pre Shaun?
Hi Keith
Not much papa experience then but all those FW amps good going for someone who started building only Yesterday :lol:
For the BA-3 I started from the standard build just to get a taste of the sound which I liked very much but when used with non FW amps it's a bit of a high gain beast. it's a good place to start for finding out what changing the gain does to the sound.
For 10DB I went belt and braces.
Calvin's (does a nice buffer) suggestion of R5 220R R6 49R R7 49R worked really well to chop down the gain tree. R13 is more subtle IMHO and 200R seems a little to much chop so I'll head back to 300R on that in the rebuild for just a little more push and a few more DB.
EASY PEASY TO TRY.
I just put 100R in parallel with R6 R7 for 50 ish Ohms and swapped out R5. makes it easier to swap around for FW amps.
The big surprise to my ears is that changing the gain even using the above methods does not change the sound tonally or in terms of detail IMHO. it still sounds big, bold and with bags of detail.
A sweetie :eyebrows:
Sovereign
14-01-2016, 22:50
We have music through the stunt speakers:D
Hopefully have a proper listen tomorrow.
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0624_zpsmxeevj89.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0624_zpsmxeevj89.jpg.html)
http://i867.photobucket.com/albums/ab236/Marra49_photos/DSC_0623_zpslnitxqqx.jpg (http://s867.photobucket.com/user/Marra49_photos/media/DSC_0623_zpslnitxqqx.jpg.html)
What are your impr impressions Marra?
Colin Wonfor
15-01-2016, 08:01
Happy New Year James we missed you see you soon.
I am very pleased with the step up in sound quality which the p/s board brings. Deep deep bass; I never thought the little speakers would go this low; superbly detailed mids and highs. Low level detail being far easier to follow and I keep thinking where did that come from hearing thing that I hadn't noticed before.
So a big thank you to Colin for making this amp available and the guys who posted pics of their builds which inspired me to give it a go:)
Sovereign
16-01-2016, 11:40
Happy New Year James we missed you see you soon.
Thanks mate !
I am very pleased with the step up in sound quality which the p/s board brings. Deep deep bass; I never thought the little speakers would go this low; superbly detailed mids and highs. Low level detail being far easier to follow and I keep thinking where did that come from hearing thing that I hadn't noticed before.
So a big thank you to Colin for making this amp available and the guys who posted pics of their builds which inspired me to give it a go:)
Hi Keith
Pretty much ties in with My own thoughts.
''IMHO, to my ears and in my set up adding the regulated PSU made a big difference to the overall sound.
A little trade off between the ‘’slightly’’ rosy presentation of the standard SECA and the grip, clarity and super resolution with the Dynamic PSU in pace. (sounds like a bigger amp to my ears)
Spooky amounts of detail. Cavernous bass, sweet but well resolved and smooth treble without any hint of harshness are stand out thoughts.
And a huge soundstage.
It’s also great fun to listen to.
Which I do
Often.
The Dynamic PSU is well worth the extra work involved with fitting it.
Keith
My spreaders where also slightly twisted (like me) but its soft metal and easy to sort with a little effort.
Much less expensive than some of the alternatives.''
I forgot to mention the huge soundstage.
Really need to get this amp downstairs and listen through the PMC's.
Colin Wonfor
24-01-2016, 17:50
The new batch of PCB are now in stock.
Colin Wonfor
01-02-2016, 18:27
Another new build by Ben.
http://farm2.staticflickr.com/1672/24665262846_d1db25cef4_b.jpg
Colin Wonfor
11-02-2016, 17:04
The new non KIT SECA 22W only with Dynamic and bootstrap PSU.
https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xat1/v/t1.0-9/12688312_1555314411453584_6042808847073498828_n.jp g?oh=602c4f29147a3a67fc044e502b968aee&oe=5736D0D6
Colin Wonfor
17-02-2016, 10:00
Many people have now built this kit it would be nice to have a few comments positive and negative ones please. (be gently):lol:
Sorry Col but I'm going to have to be brutally honest and say that this is one of the best amps that I have ever built:D:D
From the deep bass to the treble the amp present music in a most detailed and dynamic manner starting and stopping with transients so quickly and sounding far more powerful than the 12/14 watts it outputs would have you believe and being not the least bit tiring to listen to even after several hours.
A big thank you from me. Got me wondering about the preamp now;)
Colin Wonfor
17-02-2016, 21:58
Now steady brutal honesty will make me wimp in the corner, thanks lovely to hear ;)
Look out for the 100W/Ch coming soon not in kit.
I totally agree with Keith
The standard SECA is really good and adding the dynamic PSU makes it sound even better.:)
And just to add to Keith's thoughts.
The Dynamic PSU really does lift the sound into the ''something rather special'' category.
It’s so detailed and dynamic.
Compared to other class A’s that I’ve heard which can tend impose their own sound the SECA clearly allows me to hear the difference between my DAC’s/Phono stages.
It also sounds muscular without throwing the usual wet blanket over the bass.
Sounds like no other Class A that I’ve heard to date.
Big, Bold and yet smoothly detailed.
A truly wonderful amp/s (I have mono blocks) and well worth the time, effort and cash to build.
Now steady brutal honesty will make me wimp in the corner, thanks lovely to hear ;)
Look out for the 100W/Ch coming soon not in kit.
That should be interesting to see/hear Col.
Colin Wonfor
22-03-2016, 10:20
This tiny amp is 18W/ch and is based on the Atom
http://www.audiohum.es/WebRoot/acens/Shops/audiohum_es/514B/37EA/66F2/7D3A/2710/0A01/00CB/E673/2322000001.jpg
We will not be supplying the complex over priced case work but recommend this one
http://uk.farnell.com/hammond/1455t1601bk/case-aluminium-52x160x160mm/dp/1511219
More can be found here.
http://www.audiochews.com/discussion/1848/tellurium-q-atom-amplifier-low-cost-modification-for-improved-power-and-sound-quality#latest
The estimated build cost will be less than £200.00 far less expensive than the original Atom at close to £1500.00.
Here is the original spec
Class B power amplifier with a special sliding bias into A. Low power rated but with a sound that completely destroys the notion that you need power to give a big sound.
Output power: 18W/ 8ohm
Out put maximum voltage swing; 30V peak-peak nominal
Maximum Gain: 19dB
Frequency bandwidth: 5Hz - 300Khz flat response
Frequency bandwidth: 2Hz - 300Khz -3dB
Phase angle change 0 degrees +/- 1 degree 85Hz to 300KHz
Power supply:
Power consumption approx 5W while silent
80VA toroidal
Mains fuse 3A
PSU fuse 2A
2 loudspeakers protection 5A fuses
Physical specifications:
Size: 170mm X 185mm X 55mm
Weight: 1.95kg
Here is mini review
http://audiochews.com/discussion/903/tellurium-q-listen-pre-amp-and-atom-power-amps
Colin Wonfor
14-05-2016, 06:46
My Ugly SECA the first one I made has gone to a better home in Sweden, now I will have to build another. :doh:
Colin Wonfor
02-06-2016, 17:57
Also I have rearranged the PSU which h with this simple mod will force the PSU board to close down in constant current mode. Less chance of smouldering FET,s
Change R10 to 1K and R11 to 10K, Change R13 to 1K and R10 to 10K as in this circuit.
http://i1148.photobucket.com/albums/o580/colinwonfor1/main%20reg_zpsekfgsj3n.jpg
Sovereign
04-06-2016, 15:31
i have a slightly unique 50W SECA
As the chaps above mentioned, I've never heard anything like it. In the past I've had top end Naim, top end NVA, and top end big valve amps. Compared to the 50W SECA (or is it meant to be 40W, I can't remember) the other amps seem very small, like listening through a letter box. Put the SECA back in the system and the huge sound stage is back. Wide and deep, listen and weep :lol:
I've also had the TQ Iridium which I had to sell an awful lot of gear to afford, which I have now sold, so make up your own mind here.
So thanks to Colin for making all this accessible to us.
Sovereign
05-06-2016, 09:33
Some more comments from a friend of mine regarding another one of Colins SECA designs, this chap has been into class A for MANY years and his house is littered with top end class A designs.
Below is is a collections of texts to me.
James Hi
First thoughts on the amp are that it is very good indeed. Completely silent. Many of my favourite amps did a few things very well. This seems to do them all. Perhaps at the expense of having a little less presence/attack and bass slam compared to the Bedini but that is perhaps somewhat exaggerated in these areas.
But very happy with initial listening.
Cheers
Good question. The TDS triumphed in musicality, warm and laid back. Truly excellent with classical and strings. But holds back on imaging and sense of live performance that the Class A gives me. I tend to listen to a lot of world music that likes a little more edge to the percussion.
Agreed. Now playing with and without my Sugden Class A preamp to what the effect is direct from my digital source with its own analogue gain control. Will report in due course.
Further to my last.
It was out with the preamp and in with the mains conditioner and....yes.
Already knew it was a very good amp, now know it is a truly excellent amp. Bass fully extended, faster sound overall, lower mid range extraordinary and clear and crisp on top. Sound stage truly immersive.
As they say, addictive.
Cheers
Chris
Colin Wonfor
10-06-2016, 12:47
This tiny mod could add up to another 7W to the SECA without a heat increase.
https://scontent-lhr3-1.xx.fbcdn.net/t31.0-8/13403228_10209800316468858_3302362572801648789_o.j pg
https://scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/13407167_10209800316748865_4027730733939805495_n.j pg?oh=66f2364789110a0fa977441659452f48&oe=57CC6C8C
With the earth plain remove so you can see the tracks (do not remove the Earth Plain on your PCB).
https://scontent-lhr3-1.xx.fbcdn.net/v/t1.0-9/13419234_10209800348549660_7436455212152769774_n.j pg?oh=56608e656b2c25ae18d5843033b29a04&oe=57C62425
Thanks for the updates Col.
What are the benefits for this already excellent sounding amps.
Colin Wonfor
10-06-2016, 20:47
Deeper Bass with impact, dynamic a lovely top end and will drive those "Cans" some folk call speakers with SPL of 86db.
I guess it's time to warm up the soldering iron again:)
Colin Wonfor
18-06-2016, 06:07
I thought it was time to put all the SECA stuff from all you comments in one place so please free to add to it.
http://seca.freeforums.net/
Colin Wonfor
16-07-2016, 16:59
This version of my SECA design includes the Dynamic PSU and the Bootstrap as used in James (Sovereign) amp.
Price of the PCB by e-mail only. Please also note there is a lot of SMD parts so not for the faint of heart.:eyebrows:
http://i1148.photobucket.com/albums/o580/colinwonfor1/50w%20seca%20PCB_zpsjvyc4ow0.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/50w%20seca%20amp_zpsmldxqdzy.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/50w%20seca%20psu_zpsbibryev0.jpg
http://i1148.photobucket.com/albums/o580/colinwonfor1/50w%20seca%20relay_zpse0cijnoz.jpg
Here is James link.
theaudiostandard.net/thread/1383/sovereigns-new-40w-seca-class
Sovereign
16-07-2016, 17:49
That link doesn't seem to work, try this one.
http://theaudiostandard.net/thread/1383/sovereigns-new-40w-seca-class
How does the new board compare to the original kit pcb as regards power output and heat dissipation Col.
I will have to read Sovereigns build thread.
Colin Wonfor
16-07-2016, 20:52
You will need large heatsink, but the heat dissipation is lower than one would expect.
Flat out 50W is possible, James,s got close, and heatsinks can be handled without burning.
Colin Wonfor
16-07-2016, 20:53
That link doesn't seem to work, try this one.
http://theaudiostandard.net/thread/1383/sovereigns-new-40w-seca-class
Thanks James.
See you next week.
Sovereign
16-07-2016, 22:05
You will need large heatsink, but the heat dissipation is lower than one would expect.
Flat out 50W is possible, James,s got close, and heatsinks can be handled without burning.
I don't find my amp get hot st all, when driven hard it just gets nice and warm.
Thanks guys. It looks as bigger sinks than I have are required.
Do the output devices need to be matched?
Colin Wonfor
17-07-2016, 09:08
No they are sharing well but this will depend on the coupling to the heat sink and they are all same temperature (or close).
200W power consumption with 0.23C/W sinks gives a temp rise of 46C so my heatsinks are definitely too small.
Colin Wonfor
22-07-2016, 18:22
Frying tonight :mad:
Colin Wonfor
27-08-2016, 03:28
Marra did you up the size of the heat sinks? Here in London the garden got to 38C on Weds so my SECA got very warm, so I played Mungo Gerry and the Beech Boys.
Col it didn't quite get that high up north but plenty warm enough.
Regarding the heatsinks it's a work in progress as you might say. Finances and energies being required elsewhere at the moment but hopefully by the new year I will be in a position to contemplate a new build. I would love any information re the new amp boards and build guide if at all possible.
Colin Wonfor
28-09-2016, 06:28
Very Odd I replied to this yesterday before the new kitchen and minor flooding came.
Right the PCB that James uses biased up and a increase in voltage will give 50W it is in fact the original PCB which I thought I had lost the artwork for, the problem will be in the 40W version the heat sink will rise between 15 - 20C above ambient and with lovely kids about like James darling, I did not want them to get damaged,
But by increasing the bias and voltage you will get on testing 52W and a heat sink temperature increase above ambient depending on standing and clearance between 18-25C.
So the PCB we have are the same as James but will do the job so go get them lads.
But do have fun and any problem do contact me here.
Sovereign
28-09-2016, 07:35
This is great news that you would make more of these boards available Colin, because the amplifier I have is just outstanding. If you use solder paste and are fairly steady with your hands the SMD parts are fairly easy to fit and you should get a nice neat finish , The rest of the build is fairly easy. And the payoff is simple, a truly wide, deep, powerful and detailed sound for sensible DIY prices :stalks:
Would a pair of these be sufficient for a stereo amp?
http://uk.rs-online.com/web/p/heatsinks/9033107/
Colin Wonfor
28-09-2016, 19:29
If the figure are right then nice, they should do job OK
Colin Wonfor
28-10-2016, 11:50
It appears that the 33,000uf @ 35V are getting harder to find, you can replace these with 22,000uF/35V or 27,000uf/35V with no change in the sound.
Colin Wonfor
28-10-2016, 16:07
This one looks good and in stock.
uk.farnell.com/cornell-dubilier/slp223m035h9p3/cap-alu-elec-22000uf-35v-snap/dp/2361782
Colin Wonfor
09-11-2016, 08:00
FUN FUN FUN and God loves duck to they make him giggle and with my stick I waddle also he he. Nerves now take over from pain he he.
The H.A. was due to silly practitioner telling me to stop warfarin whilst I was on Anti Bods, but the Mech Valve (not tube) jammed and bang H.A. so be warned it bloody hurts a lot.
So the next two days up the hospital for checks and the tame Vampire, (red-headed nurse jummy) .
Back in mid Novs from honey-moon so you lots take care best Wonf.
Sorry to hear that Col. I hope you are soon back on your feet and wish you well.
Sovereign
09-11-2016, 09:04
Get well mate
walpurgis
09-11-2016, 10:00
Wish you the best Colin.
Good to see you're ok so to speak. Thought my joke pm might have finished you off lol.
All the best for a speedy recovery.
Colin Wonfor
10-11-2016, 15:37
It did I am now in a coma sorry a Comer Van phew. Back in 15 dys
It did I am now in a coma sorry a Comer Van phew. Back in 15 dys
Lol Comer van, now you're just showing your age lol.
Our decontamination unit when I joined the brigade in '83 was a Comer, talk about high tech lol
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