Anyone have a schematic for this amp. It's a white one and has REV A on the board with 6000.0114?
I tried Phoenix Gold tech support but they can only send owners manuals🙁.
Just want to make sure the previous repairs used the correct parts.
I just finished replacing all the caps.
Oh, MCM had these still.... 2SC2389. Kinda hard to find...
Thanks all.
I tried Phoenix Gold tech support but they can only send owners manuals🙁.
Just want to make sure the previous repairs used the correct parts.
I just finished replacing all the caps.
Oh, MCM had these still.... 2SC2389. Kinda hard to find...
Thanks all.
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PG never openly released schematics but you never know now do you?
What parts are you worried about? Maybe I can help some...
What parts are you worried about? Maybe I can help some...
Been a while😀... I guess I could draw the dang thing. Well It works but there was a 40amp fuse installed😕. I think maybe a 20 to 30 should do as the dual diodes are the 16 amp type times 2 but don't know for sure.
I get a small tick during turn on but not off. I think it is caused by some DC offset😕. I measure about 45mv on each channel. If I touch one of the 2SC2389 or 2N4403 it drives dc down quite a bit. I circled them. I think these are part of the feedback circuit😕.
It sounds very good for such a small amp, I was truly surprised.
Any way, It's easier testing with schematics.
Oh, what delicate gold traces, OMG!
😎
I get a small tick during turn on but not off. I think it is caused by some DC offset😕. I measure about 45mv on each channel. If I touch one of the 2SC2389 or 2N4403 it drives dc down quite a bit. I circled them. I think these are part of the feedback circuit😕.
It sounds very good for such a small amp, I was truly surprised.
Any way, It's easier testing with schematics.
Oh, what delicate gold traces, OMG!
😎
Attachments
Lets look at a single channel say the left channel.
Q101 & Q102 are 2N4403 and they connect to Q103 & Q104 2SC2389's which are your diff input pair so I am thinking those 2N4403 might be current sources along with Q105 a 2N4401 which connects to the other rail supply feeding those 2SC2389 input transistors.
My crib notes say the 30 amp fuse was changed to a 40 amp fuse, so I think you might be OK there.
I found on PG amps if they exhibit high DC offset its a good starting place to replace the diff input pairs. They like in many other amps seem to take a beating with age. You can squirt some freeze spay on them and watch the offset dance around if you like 🙂
Why don't you drop me a email sometime....😉
Q101 & Q102 are 2N4403 and they connect to Q103 & Q104 2SC2389's which are your diff input pair so I am thinking those 2N4403 might be current sources along with Q105 a 2N4401 which connects to the other rail supply feeding those 2SC2389 input transistors.
My crib notes say the 30 amp fuse was changed to a 40 amp fuse, so I think you might be OK there.
I found on PG amps if they exhibit high DC offset its a good starting place to replace the diff input pairs. They like in many other amps seem to take a beating with age. You can squirt some freeze spay on them and watch the offset dance around if you like 🙂
Why don't you drop me a email sometime....😉
So Q105 is also a suspect? I've ordered the 2N4403 and the 2SC2389. Will have to order some 2N4401's.
Had good luck with CENTRAL Semi's on those Zapco diff input pairs getting the offset down below 10mv. Must have received a good batch from mouser. Oh, will do on the email.😎
Had good luck with CENTRAL Semi's on those Zapco diff input pairs getting the offset down below 10mv. Must have received a good batch from mouser. Oh, will do on the email.😎
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