SECA KITS Diy

[Colin Wonfor]

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.

[Colin Wonfor]

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.

[Ali Tait]

What power do you get from these Colin?

[Colin Wonfor]

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]

Ok thanks.

[Colin Wonfor]

Ok thanks.

You are welcome.

Col

[Puffin]

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]

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.

[Clive]

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]

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.