Odd C-80 preamp issue

Playing with a newly repaired C-80 hooked to a new to me m-45, everything sounds great, looks great except for a speck of dust on the top of the C80.

I wiped at the dust with the back of my little finger and my left speaker crackled/distorted. The sound was louder than the music playing at a low volume.

I powered down, checked all connections and tried again.

It is repeatable everytime, and not static.

I have never noticed this before with this unit, my c60 or cx1000..

Any idea what might be going on?

Tap on the top cover. If it crackles and pops -- cold soldered connections.

Key suspect are the copper buss bars soldered to the PC board, pass transistors in the power supply and RCA jacks on the rear. Can confirm the RCA'a by wiggling the cables.

avionic said:

Tap on the top cover. If it crackles and pops -- cold soldered connections.

Key suspect are the copper buss bars soldered to the PC board, pass transistors in the power supply and RCA jacks on the rear. Can confirm the RCA'a by wiggling the cables.

Click to expand...

Thank you,

Ironically those are the EXACT things I was just charged for fixing when picking it up with the B6..

The prior symptom I took it in for was one channel out at first.

Substitute in different interconnects.

avionic said:

Substitute in different interconnects.

Click to expand...

Tried different cables, both to amp and from cd, and reversed the power cable as well, it still does it.

They must have missed a spot.

quite possibly your RCA terminals? Try moving your interconnects while powered up and playing music. Any feedback?

These RCA terminals are known to have poor connection to PCB.

This what I ended up doing to a C-85 last year with great results:

Are those from Parts Connex ?

avionic said:

Are those from Parts Connex ?

Click to expand...

for the C-85 I just bought bulk off the bay. I could have done better but they are still much, much better than the stock connectors!

here is the mod link http://www.audiokarma.org/forums/showthread.php?t=448504

When I did the C-2x I used some higher quality units from parts connexion.

I also used the external retaining nut version on the C-2x which made things much easier! http://www.audiokarma.org/forums/showthread.php?t=448946