Loud pop at start-up. Now bery low volume.

[rumblebox]

So i flipped on the JSX just now and heard a loud pop. Now it has minimal volume, and there's a constant subtle hiss.

All the power tubes are lit up, and the volume still changes with the knobs... Just really quiet.

WTF

 

[rumblebox]

Re: Loud pop at start-up. Now bery low volume.

I tried a different cab, different cable, different V1 tube. No effect.

It also goes completely dead after being on for a while until it cools off.

 

[GoldenVulture]

Re: Loud pop at start-up. Now bery low volume.

My guess is a dead cap, maybe in the power supply area.

 

[Diminished Triad]

Re: Loud pop at start-up. Now bery low volume.

I had two amps with similar sounds and my tech explained while changing out tubes that if heat/time have anything to do with problem then almost always tubes. 99% of all these problems are tubes.....that's the good news. They changed out tubes on both my amps (fortunately covered by warranty) and both amps are fine. My tubes seemed to glow pretty good/even on the second amp that went out but even with that, we were down to our last tube when sure enough, that was the one. I went ahead and replaced all the tubes and kept the old ones as spares.....just in case if ever on the road and one goes out I have pretty much complete sets for each amp now. My bet is its a tubes thing, change them and you're back in business.

 

[rumblebox]

Re: Loud pop at start-up. Now bery low volume.

i ordered some KT77's to try before i start doing surgery.

 

[dr. ad]

Re: Loud pop at start-up. Now bery low volume.

^ good luck!
and remember to drain your voltages
:beerchug:

 

[rumblebox]

Re: Loud pop at start-up. Now bery low volume.

Well it was the PI tube, a short lived ECC803S.... But at least i had a reason to try out some KT77's, which i now love more than 6L6's.