DSL1 Output Issue Help

[Cousin Muely]

Guys! Need some input. The output is crackling and fades in and out. It was doing this before I retubed it so I figured it was just a bad tube. In fact at the time i thought the output was inaudible. New tubes in and it ran fine for a couple weeks until last night. Now it's doing it again. Could still be a bad tube but any thoughts?

[surfnorthwest]

Yep. proving once again that the longevity quality of new tubes are not what they used to be. Just light a light bulb new tubes can go at anytime and they let you know it.

I suspect you had one of those new tubes go micorphonic on you. Change it again and see if that works, really the only way to know for sure.

[Cousin Muely]

It's the only reasonable explanation. So, I would expect it to be one of the 12au7's?

[surfnorthwest]

Probably, but its going to be a process of elimination to figure out which one. Let me know how it goes.

[Cousin Muely]

I had put this on the back burner for a bit but worked on this over the weekend. I checked the DSL1 and it still had the fizzy low output issue so I swapped the new DSL1 tubes to the JVM1 and the JVM's to the DSL to isolate whether or not it was one of the new tubes. I've had no issues with the JVM1. Both amps worked fine. So, I swapped them all back. Now the DSL1 seems to be working fine.

I'm tempted to think that maybe I didn't seat the new tubes because I'm always concerned I'll bust one or pop a solder joint. But, what the new tubes did after a couple weeks of ownership is the same symptom the amp had and was the reason I replaced the old ones.

I'm playing this amp exclusively right now to make sure it's good to go but could there be something else? It was intermittent before.

[Alpeggio]

That's intersting, and glad it was a simple fix.
You know my H+K replex valve pedal had exactly the same problem and fix. My tech took out the valve and cleaned it up put it back in and its been fine ever since.

[burnsy]

A squirt of electrical cleaner onto the pins of a valve and plug it in and out of the socket a few times has helped me clean up suspect valve socket connections in the past.

[Cousin Muely]

Copy that guys. I have contact cleaner and thought about that after I was almost done. I should be doing this every tube swap anyway.