Weird sound from my dsl

[Kamui26]

So basically I was recording when suddenly my Jcm 2000 dsl 100 started making a popping noise louder than the clicking from being about 4-5 feet away from my computer. Then it started making this unbearable screeching noise almost like it was writhing in pain?
Would anyone maybe know why maybe like a bad tube, fuse, something like that?

that’s what it sounds like

 

[Kamui26]

I removed all pedals and plugged straight into it with a cable I’m certain works and it still does this

 

[solarburn]

I’d start checking preamp tubes/power tubes just to eliminate a bad tube. That screech noise was intense!

 

[Kamui26]

How exactly do I rule out a bad tube? This is my first tube amp and I honestly don’t know a lot about them. A couple of the power tube’s wires or connectors running in are black on camera but somewhat purple or blue?

 

[PelliX]

I'd hazard a guess that that might be the negative feedback losing contact with the circuit. I'm not sure how savvy you are, but I'd be checking the speaker jacks/secondaries of the OT. Likely a contact is breaking there allowing it to oscillate like crazy.

As Solar suggested, swap valves, but I seriously doubt that's the issue here.

 

[Tatzmann]

Pagers...Walky-Talkies...DSL's.

 

[PelliX]

Pagers...Walky-Talkies...DSL's.

*eyes his walky talkies next to the CB gear...* *squints*....

 

[PelliX]

How exactly do I rule out a bad tube? This is my first tube amp and I honestly don’t know a lot about them. A couple of the power tube’s wires or connectors running in are black on camera but somewhat purple or blue?

There is not much you can do optically. If the silver lining on top (called the getter flash) has turned white, the valve has lost its vacuum (or gained air, depending on how you look at it). That would mean it's toast. If anyting is loose inside, it's obviously broken, too. You can measure the heater filament resistance on your multimeter, but that wouldn't cause this issue.

Most likely your problem is in the negative feedback. Which output tap are you using, what impedence is the cab?

 

[Leonard Neemoil]

My DSL 100H has been doing the same exact thing. If I smack the head it'll stop. I can't play much these days and it's not here right now but iirc, the screeching also stops if I change channels.

Was planning on swapping tubes eventually. The getter is still silver on all of them anyway.

I'm using the 8 ohm tap into my V30 2x12 @PelliX.

 

[PelliX]

I'm using the 8 ohm tap into my V30 2x12 @PelliX.

I'd certainly get in there to check out what's going on. Without knowing any revisions/dates here;



It looks like the NFB is attached the 4 Ohm tap. If you can get a 4 Ohm load it might be worth checking if that works without problems. In all cases you want to clean the jacks. To be more specific, board revisions and amp dates would be required here.

 

[Leonard Neemoil]

Thanks @PelliX.

@Kamui26, how often does yours do that? Mine does it maybe 15% of the time.

 

[PelliX]

@Kamui26, how often does yours do that? Mine does it maybe 15% of the time.

When quantifying the duty cycle of a dodgy connection the result should always be rounded up to 100%.

 

[Kamui26]

Thanks @PelliX.

@Kamui26, how often does yours do that? Mine does it maybe 15% of the time.

Last night is the first time it’s ever done that, and it also take maybe about 15-30 minutes playing on medium volume for it to start doing it again but it’s a lot less intense than it was earlier or even in the video.

 

[Kamui26]

There is not much you can do optically. If the silver lining on top (called the getter flash) has turned white, the valve has lost its vacuum (or gained air, depending on how you look at it). That would mean it's toast. If anyting is loose inside, it's obviously broken, too. You can measure the heater filament resistance on your multimeter, but that wouldn't cause this issue.

Most likely your problem is in the negative feedback. Which output tap are you using, what impedence is the cab?

Uhhhh so I’m using the 16 ohm output on the head and the cab has two inputs for mono which is 16 and 4

 

[PelliX]

Uhhhh so I’m using the 16 ohm output on the head and the cab has two inputs for mono which is 16 and 4

Give it a shot on the 4 Ohm tap with the 4 Ohm input (there may also be a switch on the backplate, too, not sure what cab you have).

 

[Kamui26]

I got a 1960A from 03,
I tried the 4 ohm output and everything was plugged in right but it made this like echoey feedback sound that didn’t stop from turning down the guitar’s volume.
I’ve realized if I stand a couple feet away from the amp then the pops and squeals stop completely?

Give it a shot on the 4 Ohm tap with the 4 Ohm input (there may also be a switch on the backplate, too, not sure what cab you have).

 

[Kamui26]

Give it a shot on the 4 Ohm tap with the 4 Ohm input (there may also be a switch on the backplate, too, not sure what cab you have).

And now it’s making a high pitched rattling noise on standby and does that echoey feedback every time it’s off standby, even when plugged into the 16 ohm input and output

 

[PelliX]

I’ve realized if I stand a couple feet away from the amp then the pops and squeals stop completely?

Come again? If you unplug your gear from the input(s) of the amp, does it still squeak and so on?

And now it’s making a high pitched rattling noise on standby and does that echoey feedback every time it’s off standby, even when plugged into the 16 ohm input and output

If it's making noise with standby engaged you either have a faulty standby switch, or something is very, very wrong. Well, both those are wrong, I guess. Can you confirm?

 

[Kamui26]

Come again? If you unplug your gear from the input(s) of the amp, does it still squeak and so on?



If it's making noise with standby engaged you either have a faulty standby switch, or something is very, very wrong. Well, both those are wrong, I guess. Can you confirm?

The standby switch always confused me but no it doesn’t make sound when it’s not supposed to, idk what it did but it just fixed itself. No joke nothing I do can make it start popping and squealing again
From the looks of it, the tubes seem to be fine but are probably due in not too much longer assuming they were replaced around 2014 because a part has “replaced 12/4/14” so back in december of 2014

 

[PelliX]

There's something wrong there. Question is whether you want to tackle it.