# ppi a600.2 repair



## Camineet (Oct 20, 2011)

hi all,

can i trouble you guys to let me know if there is a reputable person currently doing repairs on these amps?

i have a near mint a600.2. i'd give it a 9.8 out of 10. pretty much flawless cosmetically as i have babied it all these years since buying it new in '96 or so.

the only flaw is on the underside of one of the mounting brackets. it somehow got some rust on it which i plan to grind out and paint. 

here's the repair needed...

the amp works very well except at low volumes, a scratchy sound can be heard in voices and horn instruments and such. it's something like a scratchy sound and not a click, crackle, or popping.

the amp still performs magnificently at loud volumes, but the low volume problem must be fixed for the amp to be truly enjoyed.

in an attempt to fix the problem, i thought i would go about recapping the whole amp. in 2016 i ordered all the caps for the job. and in 2017 i made an attempt to do the recapping.

i was only able to change one of the big caps. it was extremely difficult for me to get the old one out, and so i gave up after only swapping out this single cap. a more experienced technician can almost assuredly desolder and get these stubborn caps out much more easily than i am able to. i don't think there's anything particularly wrong with these caps. they're just old and as i understand it, solder gets harder and therefore more difficult to desolder after some years.

after my failed attempt to recap the whole amp, i reassembled it and it still works the same as before working on it. i still have the box of all the other caps that i didn't replace, and in addition to diagnosing the scratchy sound problem, am asking for the repair tech to recap the amp using the caps i bought or others if they would be recommended. perhaps the repair tech might recommend an upgrade on the caps that i wouldn't know anything about without receiving such a recommendation from someone more skilled.

thanks in advance if the diyma community can let me know my options on this


----------



## Camineet (Oct 20, 2011)

bump


----------



## mark3004 (Oct 4, 2017)

Do you ear scratchy sound just when turn the gain or always? I had a similar problem with an a/d/s and solved changing the trims...


----------



## moparnut (May 30, 2018)

Yeah it sounds like the gain trims. I had a cobalt that had the same sounds. I would probably try to find a local shop to do the repair, but if you are looking to send it off, contact the amp lab (theamplab.net).


----------



## Camineet (Oct 20, 2011)

the problem is continuous on, not just when adjusting the gain. i actually tried adjusting the gain to see if setting it to a different level would somehow break the amp out of the scratchy sound zone. no luck.

ok, thanks a lot i will contact theamplab.net


----------



## Camineet (Oct 20, 2011)

hi all, 

thanks again for the heads up about theamplab.net

the guys over there offered a very affordable recapping quote, but expressed disinterest in trying to chase down the sound problem.

is there anyone you guys can think of who is known to be inclined to dig a little deeper in the area of diagnostics and remedy seeking with these things?

i could just use the amp as a bass amp and never again run mids and highs on it. but as the amp has a good reputation for sq, i feel a bit disappointed if i have to relegate it to bass amp only status.


----------

