JCM2000 DSl100 noise issue

[Stratdan]

My JCM2000 DSL100 is making very strange noises and before I open it up to have a look, I thought I'd post a link to a recording of the noise here, for any suggestions as to what exactly I should be looking at. I'm capable of working on amps, in terms of safety, and can do routine maintenance and repairs, but I lack trouble-shooting skills and am hoping someone here can identify the problem. Thanks.


JCM2000 noise test mix by Guitarget on SoundCloud - Create, record and share your sounds for free

[Amp Kat]

My JCM2000 DSL100 is making very strange noises and before I open it up to have a look, I thought I'd post a link to a recording of the noise here, for any suggestions as to what exactly I should be looking at. I'm capable of working on amps, in terms of safety, and can do routine maintenance and repairs, but I lack trouble-shooting skills and am hoping someone here can identify the problem. Thanks.


JCM2000 noise test mix by Guitarget on SoundCloud - Create, record and share your sounds for free

Sounds like it's picking up your phone are maybe a transmitter tower. Is your phone nearby ?

[Stratdan]

Sounds like it's picking up your phone are maybe a transmitter tower. Is your phone nearby ?

No phone anywhere near the amp, nothing has changed, the amp is never moved and this just started happening recently.

[1ampman]

It sounds like a bad solder joint or a preamp tube. Can you make the sound start or stop by pounding on your amp with your fist? I assume the amp makes the noise with NO guitar plugged in? Have you had a Close Encounter? Does the government consider you a person of interest?

[Stratdan]

It sounds like a bad solder joint or a preamp tube. Can you make the sound start or stop by pounding on your amp with your fist? I assume the amp makes the noise with NO guitar plugged in? Have you had a Close Encounter? Does the government consider you a person of interest?

No close encounters, not recently anyway. I have publicly proclaimed our PM (I'm Canadian) to be a complete schmuck, so there is that.

Yes, the noise I recorded was without a guitar plugged in, but it first occurred while I was plugged in and playing, no, I didn't try pounding the top of the amp, I so don't like doing that, but I'm leaning toward the possibility of a bad solder joint. I will, however, try swapping out the preamp tubes first, as I have some new backup ones laying around. I was just hoping that someone would know this very sound, as it was odd to me. I'll put it on the bench and see what I can find. Thanks for the input.

[1ampman]

I'm curious to what you find. The preamp tube swap is an excellent place to start. Swap 1 at a time. In case it's a dirty socket or dirty tube pins. Pounding on the top with your fist is a standard procedure used by all techs. I realize it's not pretty or high tech but it will rule out certain problems. Please post your findings....

[Stratdan]

I'm curious to what you find. The preamp tube swap is an excellent place to start. Swap 1 at a time. In case it's a dirty socket or dirty tube pins. Pounding on the top with your fist is a standard procedure used by all techs. I realize it's not pretty or high tech but it will rule out certain problems. Please post your findings....

Thanks for your inquiry, I haven't yet had a chance to get a look inside, but will certainly post my findings. I actually didn't know about the fist-pounding procedure, but as crude as it is, it makes sense, as an easy way to check for cold solder problems. I will do the pound test and the preamp tube swap out this week and post the results.

[Stratdan]

This post is quite old now, but unfortunately, I wasn't able to address the problem due to other issues in my life, but I finally looked inside the amp and wanted to post the results. It was the infamous C46 cap that these DSL2000 amps are notorious for. It was a charred cinder that crumbled when I took it out. I replaced it with a 1000v cap and the amp is operating beautifully. I also retubed the output tubes and it sounds better than ever and have played it for many hours with not a single problem.