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For my second adventure in the world of diy electronics I’m building a dcb1 preamp. Buoyed by the eventual success of my first project, a Bigbottle mc phono stage, which after a lot of help from Oliver has seen a great leap forward in my system’s musicality, I thought I’d see if I could get a similar improvement in the next link in the chain.
I’ve assembled two boards and plan to get it working unbalanced first, with provision to try a balanced arrangement in the future when I can afford a 4 pole Khozmo.
It’s taken me some while to build as there were no parts kits left so I’ve had to source components individually. With my rather basics electronics knowledge (A level physics back in 77) and a bewildering choice of similar components available progress has been slow.
So the big switch on today, and…. well, nothing. No lights no signal, nothing! Any. Thoughts on where to start looking would be very welcome. Measuring the input voltage 12.6V to signal ground or 25.4V across terminals. Also there is a very gentle ‘buzz’ to the touch on the casework. No J3 installed - is that right?
Thanks for any help.
http://i65.tinypic.com/2b9u9t.jpg
http://i65.tinypic.com/sawmdw.jpg
http://i65.tinypic.com/vi2wqp.jpg
http://i68.tinypic.com/25g418j.jpg
hi , Are the 4 big Fets on the side in the right places? I made that mistake and got no lights etc check the components are in the right place. the voltages seem high, on the V+- out should be at the 9-10 v mark.
Don't worry I'm sure Steve Oliver and others will be along to help. :)
Looking at the board you have included the short jumper 2 - J2 by the V out , you don't need this it belongs to an earlier iteration of the board. . Take it out and it might work. :)
Good luck.
Check my thread pics for board close ups for comparison see the J2 jumper slot is unused. .
https://theartofsound.net/forum/showthread.php?64163-The-New-Adventures-of-the-ElectroNumpty-DCB1/page4
Bigman80
30-06-2019, 21:06
Dom,
Have you got isolation pads under the fets? If they have exposed metal on the back, I would expect this to be the problem or a problem as I can't see the rest.
Check the part numbers are in the correct places too.
PS, feel free to share your thoughts on the BigBottle, no one has yet!!! I'm starting to wonder if it's shit!? [emoji23][emoji23]
Check my thread pics for board close ups for comparison see the J2 jumper slot is unused. .
https://theartofsound.net/forum/showthread.php?64163-The-New-Adventures-of-the-ElectroNumpty-DCB1/page4
Andy - looking at your thread pics I should cut J2 but install J3 - is that right?
Dom,
Have you got isolation pads under the fets? If they have exposed metal on the back, I would expect this to be the problem or a problem as I can't see the rest.
Check the part numbers are in the correct places too.
PS, feel free to share your thoughts on the BigBottle, no one has yet!!! I'm starting to wonder if it's shit!? [emoji23][emoji23]
Oliver
I only have clear mica TO220 pads in for isolation - theyre a bit small and I see one is a bit squiff, I see if I can get bigger ones to be sure.
BTW really pleased with Bigbottle phono now. I'm not good at reviews, but it has a much more fluid and musical sound than my previous Dino - defo NOT shite at all....
Bigman80
30-06-2019, 21:43
Oliver
I only have clear mica TO220 pads in for isolation - theyre a bit small and I see one is a bit squiff, I see if I can get bigger ones to be sure.
BTW really pleased with Bigbottle phono now. I'm not good at reviews, but it has a much more fluid and musical sound than my previous Dino - defo NOT shite at all....Haha, thanks Dom. That'll do me nicely.
I'd double check that there's isolation there. Get a multimeter on the connectivity setting and just check that centre screw and chassis aren't connected.
Other than that, I'm at a loss.
Andy - looking at your thread pics I should cut J2 but install J3 - is that right?
Hi Dominic
By J3 do you mean the jumper that replaces the 2 resistors as per the note on the board? For the
12v relay? I guess yes.
J2 is the only jumper not used unless the relay is less than 12v.
looks like you're using the same hook up wire as I did, it will sound fine then! ;)
Oliver I'll be building the Bigbottle over this winter, I'm sure it's not shit! Even if it is the board looks nice!lol :)
Bigman80
30-06-2019, 22:10
Hi Dominic
By J3 do you mean the jumper that replaces the 2 resistors as per the note on the board? For the
12v relay? I guess yes.
J2 is the only jumper not used unless the relay is less than 12v.
looks like you're using the same hook up wire as I did, it will sound fine then! ;)
Oliver I'll be building the Bigbottle over this winter, I'm sure it's not shit! Even if it is the board looks nice!lol :)Lmao, I know it's not mate [emoji6]
Just one thought. Leaving transformer wires drifting like in the photo is asking for trouble. At least put them in an insulated terminal block before you ask for advice. As it is you are asking for advice about a potential homicide.
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Bigman80
30-06-2019, 23:06
Just one thought. Leaving transformer wires drifting like in the photo is asking for trouble. At least put them in an insulated terminal block before you ask for advice. As it is you are asking for advice about a potential homicide.
Sent from my BLA-L09 using TapatalkI may be wrong but I don't think that TX is connected looking at the pic?
Hi Dom
Its silly oclock but I'm awake.
I can see a few small errors in your build that need sorting before you power up.
Will pm you when its a more reasonable time.
Steve.
I may be wrong but I don't think that TX is connected looking at the pic?In light of morning you appear correct, thanks for this, my post is rather overstated, so also apologies to the op. I still maintain that loose power circuit wires, at any stage, should be tidied away from any mains connections, at the very least with the bare ends taped off. It's too easy to brush past those wires whilst checking, with the potential for all sorts of harm.
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Bigman80
01-07-2019, 11:15
In light of morning you appear correct, thanks for this, my post is rather overstated, so also apologies to the op. I still maintain that loose power circuit wires, at any stage, should be tidied away from any mains connections, at the very least with the bare ends taped off. It's too easy to brush past those wires whilst checking, with the potential for all sorts of harm.
Sent from my BLA-L09 using TapatalkYes, good practice to get everything safe as it's easy to forget and hook it up without realising
So, thanks to everyone who has made suggestions and given advice. So far I have:
- cut link J2 (though understand this link is now within the board anyway)
- installed link J3
- installed second parallel link at 2 x 600? position
- checked no continuity between FETs and case
- ordered larger isolation /thermal transfer pads to go under FETs
Still no leds light when powered and V+ and V- too high at over 16V DC.
I’ll try again at the weekend when new isolation pads arrive. Next up I’ll start replacing leds one by one. Then if still no joy it’s time to ‘phone a friend’.
Dom
Keep plugging away at it Dom , I had to send my board to Alan (Firebottle) of this parish to trouble shot for me. Its worth the wait once up and running. Good luck !
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Btw have you tried power through the other board? If you swap it over that one might work. ?
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I thought I had gone to so much trouble to get the LEDs in the right way round, but alas not. I just tested them all with a battery and resistor circuit. The good news is they all still work. The bad news is the orange work the opposite way round to the clear(red when on) leds. The orange light when +ve connected to the square terminal and the clear-red only light when +ve connected to circular pad. I checked on two unused LEDs and orange light with +ve on the long leg while clear light +ve on short leg. WHICH NEED TO BE TURNED AROUND??
http://i66.tinypic.com/mwzmyw.jpg
http://i65.tinypic.com/29mxems.jpg
weird I thought all short leads were negative ? all polarity as per the board i think really. from memory +ve on the circle side and -ve on the flat side. Someone less numpty like will be along to confirm/deny shotly I imagine. [emoji846]
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Bigman80
04-07-2019, 20:50
weird I thought all short leads were negative ? all polarity as per the board i think really. from memory +ve on the circle side and -ve on the flat side. Someone less numpty like will be along to confirm/deny shotly I imagine. [emoji846]
Sent from my SM-G950F using TapatalkThe +ve and the -ve are the same on both the leds in the picture to check which way round you have them. Personally. I'd make sure I used the same LEDS all over. .
Use the pic below to checkhttps://uploads.tapatalk-cdn.com/20190704/554526863d9e698b6af64c07ac338748.jpg
Hi Dominic
I said it would be the led.
I'm still happy for you to pop over.
I'll check everything else and i also have a set of
Audio Note resistors here if you want to fit them,they make quite a difference.
Look at position you fit led and check board marking not square or round hole mate.
Simple mistake....
Steve..
The +ve and the -ve are the same on both the leds in the picture to check which way round you have them. Personally. I'd make sure I used the same LEDS all over. .
Use the pic below to checkhttps://uploads.tapatalk-cdn.com/20190704/554526863d9e698b6af64c07ac338748.jpg
The photo of five LEDs look the right way round according to the picture, but the two clear-red LEDs measure the 'wrong' way round - ill swap them and see what happens. BTW I added the two clear-red because the total Vf measurement was getting too high with 5 orange LEDs.
Bigman80
04-07-2019, 21:57
The photo of five LEDs look the right way round according to the picture, but the two clear-red LEDs measure the 'wrong' way round - ill swap them and see what happens. BTW I added the two clear-red because the total Vf measurement was getting too high with 5 orange LEDs.How strange!
Fair enough, adding the clear ones.. Makes sense.
Hi Dominic
I said it would be the led.
I'm still happy for you to pop over.
I'll check everything else and i also have a set of
Audio Note resistors here if you want to fit them,they make quite a difference.
Look at position you fit led and check board marking not square or round hole mate.
Simple mistake....
Steve..
Thanks Steve,
I'd like to call round and have you 'cast your eye over' in any case. Ill get in touch when Ive had another try with the LEDs this weekend. I want to try with the Shinkoh and Riken before fitting Audionote resistors. Probably want to experiment with better caps too, obligato or Jantzen silver perhaps. Hope all went well with your dad.
Dom
Hi Dominic
Look forward to meeting you.
He moves to the care home on Monday :wah:
Check post 5836 might be relevant.
https://www.diyaudio.com/forums/analog-line-level/171715-salas-hotrodded-blue-dcb1-build-584.html
Bigman80
05-07-2019, 10:22
To save workhttps://uploads.tapatalk-cdn.com/20190705/bda53e7c560d1b0c00a10e5ee9012d3d.jpg
Spun the critters and it seems to have done the trick! Ive learned that I don't like resoldering :( one more board to go *X@!!
Some quick measurements on first board suggest its running at about 450mA and an extra 64Ohms in parallel is needed across one resistor to balance. Is this worth worrying about.
+ve -ve
Vout 9.61 9.57 V
Vdiff across resistor 1.216 1.167 Volts
R 2.7 2.7 Ohms
I 450 432 mA
Rbal req 2.59 Ohms
R2 req 64.3 Ohms
http://i63.tinypic.com/1567leg.jpg
Still - chuffed to get it running - thanks for advice
Bigman80
06-07-2019, 09:16
Spun the critters and it seems to have done the trick! Ive learned that I don't like resoldering :( one more board to go *X@!!
Some quick measurements on first board suggest its running at about 450mA and an extra 64Ohms in parallel is needed across one resistor to balance. Is this worth worrying about.
+ve-ve
Vout9.619.57V
Vdiff across resistor1.2161.167Volts
R2.72.7Ohms
I450432mA
Rbal req2.59Ohms
R2 req64.3Ohms
http://i63.tinypic.com/1567leg.jpg
Still - chuffed to get it running - thanks for adviceWell done!
I'd get it as close as possible, it would niggle me lol. IIRC we had to add a resistor to one channel to match it up on mine.
Nicely done. Enjoy the listening it really is a nice sounding pre/buffer. I really must try hotrodding mine at some point.
Great! it's a very satisfying feeling when it lights up for the 1st time [emoji846]
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