[tintin47]

My CK2III has worked flawlessly for the past month, but last night it exhibited a really strange issue. When I powered it up, the right channel worked for about three seconds and then the volume dropped and it became really distorted and "crunchy" (like crunchy distorted guitars) sounding. This morning, I powered the amp back on and it worked fine for about three minutes, and then the same thing happened. What could be causing this? I am assuming it is the failure of a component, but which one could it be and why would it fail now? The left channel works flawlessly.

 

[MoodySteve]

What I would do is this:

After the amp has been powered on long enough for the right channel to degrade, measure the node voltages on both the left and right channel, comparing to each other and to AMB's posted schematic with operating points. This will likely isolate the area of the problem.

After the problem has surfaced, does jiggling signal wires around affect the sound? A problem that occurs after a few seconds/minutes almost sounds like a very questionable connection that is made or broken by thermal expansion/contraction. </shot in the dark>

 

[tintin47]

Quote:

Originally Posted by MoodySteve /img/forum/go_quote.gif What I would do is this: After the amp has been powered on long enough for the right channel to degrade, measure the node voltages on both the left and right channel, comparing to each other and to AMB's posted schematic with operating points. This will likely isolate the area of the problem. After the problem has surfaced, does jiggling signal wires around affect the sound? A problem that occurs after a few seconds/minutes almost sounds like a very questionable connection that is made or broken by thermal expansion/contraction. </shot in the dark>

I agree. I thought to do that, but now the amp has been on for 2 1/2 hours and there are no problems. I moved some of the wires around this morning, so I suppose it could be a bad connection, though that seems unlikely as all of the connectionsare directly soldered. I don't know whether to hope that it resurfaces or not.

 

[MoodySteve]

This sounds like some kind of mechanical problem to me. I'd go over all of your wiring joints and reflow them.

Also make sure that your left RCA jack isn't shorted to the chassis.

 

[sachu]

Quote:

Originally Posted by MoodySteve /img/forum/go_quote.gif This sounds like some kind of mechanical problem to me. I'd go over all of your wiring joints and reflow them. Also make sure that your left RCA jack isn't shorted to the chassis.

Agree with moody here..

Reflow the RCA jacks, Pot and output connections.
Check for isolation as suggested above.

 

[tintin47]

Sounds like a good plan. Hopefully that will clear up the issue. I just can't get free and clear with this amp. Oh well. It sounds good most of the time.