Aleph J Schematic

coffee break 🙂
 

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phew ... finished
both channels are dead silent
when i connect signal from preamp on one channel this starts to put out 1Vac if I reverse signal conectors the problem persists on the same channel, if I pull the conector out dead silent again.
I guess it`s a ground problem but from where ?
each aleph is conected to earth via 2x 1n4007 soldered contrary one to another
ok... I powered up only that channel and only him connected to preamplifier...problem persists and this time he blown away the 2A fuse too
 
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Reviving Aleph J project...

My Aleph J project stalled last spring as some problems arose, but now with the serious cold weather outside, my living room could use a little more heat! 😛

I'm starting my build audit with the power supply, in which a few MUR3020s failed. I'm a nube and this is my first Pass project - I have no previous experience with FREDs. I thought a simple picture would help, so looking at the attached representation of Peter Daniels' PS boards:

1) Please match each red number with the correct black number. 😀 [Antek AN-5224 transformers - dual mono]
2) Is it OK to tie the grounds where the green lines show?

...and two questions for later related to the IRFP 240s:

3) Is there any way to check if they are OK without desoldering and removing them?
4) Assuming I get all other issues sorted out, the final operating temperature of Q5 and Q6 is likely to be a few degrees higher than the temperature of Q7 and Q8 (due to airflow over the heatsinks, which will be adjustable). Is that a problem?

Many thanks in advance for any/all advice.

Frank
 

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managed to set the dc ofset on the channel that oscillates at 0mV, did this with input shorted and after an hour when it got warm.after that I did another test which consists into conecting only the ground of the amp to the ground of the preamp and in this case I see nothing on my dmm but when I connect ground and signal + it begins oscillating, curious that in this time it blew away the other channel fuse too

what could it be? input J`s ? goes beyond over my head...

have to mention that I did another test with the earth disconnected from the amp...still the same
 
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