Heavy Distortion

[bmnathe]

Hey guys - I bought my kit assembled from the first owner.  It worked great for a couple of months until recently - it started producing heavy distortion at any volume level; seems to be mainly from the lower frequencies.  I don't have much issue until a track with bass is played.

When I first received the kit, I noticed that two wires were misplaced (reversed) on the balanced jack.  I fixed that and no issues.  Since the distortion started, I re-soldered nearly every joint and biased the tubes a few times (not much drift).  Besides verifying correct wiring, soldering, etc. on the actual amp - I have tried different sources, power plug, power supply, wiring. 

The tubes glow like normal.  I noticed that one power tube is a bit microphonic when I touch it.  This tube seems to produce the most distortion (checked by swapping channels) although both channels are distorted. 

Anything else I should check before I buy new tubes?

thanks,
B

[Paul Birkeland]

Have you checked all the voltages? 

[bmnathe]

Have you checked all the voltages?

Yes - I check all voltages and resistances - everything checks out.  There's no obvious signs of capacitor damage - no leaking or bulging.  All ground wires and nodes are grounded.

[Doc B.]

Have you changed anything upstream or downstream of the amp, like headphones or source?

[bmnathe]

Have you changed anything upstream or downstream of the amp, like headphones or source?

No - all sources, cables, power source, etc. is the same as when the mainline was working well.

[Paul Birkeland]

My best guess is that you have a flaky solder joint that's common to both channels.  I've had issues like this pop up on Cracks when there's a bad solder joint somewhere on the shared ground buss.

[bmnathe]

My best guess is that you have a flaky solder joint that's common to both channels.  I've had issues like this pop up on Cracks when there's a bad solder joint somewhere on the shared ground buss.

thanks - I'll double check it but I re-soldered everything already..

[bmnathe]

Guys - I did nothing else and the issue has 'magically' resolved itself.  Not sure what the issue ever was.....I didn't even touch the unit.  I don't think it's a power supply issue because I run through a voltage regulator.  I am still going to install new tubes because one power tube is a bit microphonic....

thanks!
B