A little help needed with a Pass Aleph 30

[johnsonad]

Hello,

A couple of days ago I decided to repair a loose RCA jack on my factory Pass Aleph 30 amp. I opened up the top, tightened down the set nut on the inside and relieve a few of the extra turns it had over the years. While inside I gave it a light dusting.

Put it together, fired it up and it sounded great until it reached full temp. In the left channel only (the side with the loose RCA) during high dynamic passages it started to distort, making a crackling sound and the volume started to fade in and out only in that channel and only at full temp. I shut it down, and the next morning did a thorough cleaning with a tooth brush and 99% isopropyl alcohol as the boards were pretty dirty still. Let it dry out over night, put it back in the system and tried it again. Same problem at full temp only. Switched left and right channel inputs to see if it was in the source or preamp. Still in the left channel only and still only at full temp (after 30 mintues or so, hot to touch, can’t hold the heat sinks more than a couple of seconds). Additionally, when shutting down the amp, during the usual low thump when the speaker cone moves out a little, there is crackling distortion in the left channel only.

I’m wondering if the RCA jack could cause this? If so, I can remove the heat shrink and check the solder connections at the jack. I could also just replace the jack while it is open. Or, did I cause another problem when I was cleaning?

Thank you in advance.

Aaron

[Zen Mod]

it's really hard to say without exact insight in amp .

can be many things - loose solder contact , or even worn cap , finished with slight touch .

anyway - it probably needs some thorough care , after all these years ;

maybe few small electrolytics on pcbs are most suspicious

can you make any good photo of inside ?

[johnsonad]

I can post a couple of pics tomorrow. The boards are good and clean on the tops at least. There are a few small lytic caps on the boards and I may have moved them a little in cleaning.. Hmmmm.....

Maybe it's time to send it off for a tune up...

[Zen Mod]

if you aren't even remotely sure in what you're doing , it's better to send them to someone who is ;
this amp deserve good care and love ..... it's just like your dearest ugly dog

[johnsonad]

Well said. I emailed Wayne and the guys at Pass Labs. I don't want to cause more harm than good. I know just enough to be dangerous!

[Zen Mod]

Originally Posted by johnsonad

.....I emailed Wayne and the guys at Pass Labs.......

who they are ?




put a note on top cover - "ZM sez that's my ugliest dog! " and they will charge you a double