Amp making weird noise when volume turned down?

[Brow]

Hey guys.

I've bought a new mic today so thought I'd set some stuff up and record something for a laugh now I finally have my new PC I've needed for ages!

I decided to use my Matamp Little Rock 4w head and 1x12 as I couldn't be bothered to drag the Splawn and 2x12 downstairs and after a bit of playing the amp started making an odd noise, even with the volume control on the amp turned down and nothing plugged into it.

The only thing I can compare it to is when you shake a broken guitar lead and the sound crackles, but that doesn't explain why it'd do it with nothing plugged in.

I've attached a small recording of the noise, which I've had to normalize due to the mic preamp level being low as
the amp wasn't being used at the time so I turned it down.

Is it anything I should be concerned with or just a dodgy valve etc?

Thanks!

Craig

[darkbluemurder]

Does it also do this when you got a guitar plugged in with the guitar volume down? If it does not do it then but only with nothing plugged in, the switch contact on the jack does not work correctly anymore. The jack should then be cleaned or replaced.

If it keeps on doing this with a guitar plugged in with the guitar volume down I suspect a bad preamp tube.

Good luck
Stephan

[Brow]

Does it also do this when you got a guitar plugged in with the guitar volume down? If it does not do it then but only with nothing plugged in, the switch contact on the jack does not work correctly anymore. The jack should then be cleaned or replaced.

If it keeps on doing this with a guitar plugged in with the guitar volume down I suspect a bad preamp tube.

Good luck
Stephan

Thanks for the reply.

It sometimes does it when nothing is plugged in and it sometimes does it when I'm plugged in and playing.

It just so happened that there was nothing plugged in this time as I was working on a backing track instead

[marauder]

My Lionheart did that when the standby switch was failing.  It was arcing for a few seconds when turned on, and intermittently cutting the power to the OT and power tubes.   There was a very quiet crackle from inside the switch, but hard to hear as it was also heard through the speakers.

[Brow]

My Lionheart did that when the standby switch was failing.  It was arcing for a few seconds when turned on, and intermittently cutting the power to the OT and power tubes.   There was a very quiet crackle from inside the switch, but hard to hear as it was also heard through the speakers.

The power switch currently in the amp is the 2nd 1 as the 1st 1 blew up because it was arcing, Matamp sent me a new switch free of charge though as the amp wasn't very old when it started happening. I can't remember if these noises happpened the last time the switch went or not  :lol:

[ratspeak]

My amp has this problem perpetually. It may be a switch, but mine's been doing this for nearly a year and nothing's blown up yet. At least it doesn't come through on recordings.

[Frank]

You might have a tube on the way out there, internal arcing can make those kinds of popping noises. Or it could be a dry solder joint somewhere, those are always fun to try and troubleshoot.

[HTH AMPS]

first things to check if your amp is making weird noises with nothing plugged into it...

* replace valves one by one (to isolate the dodgy one if it is indeed the valves)
* clean the pots with a lubricating aerosol spray (I use Servisol Super 10)
* clean the valve bases and jack sockets with a solvent aerosol spray (I use Servisol Aero Klene 50)

when cleaning the pots, rotate them round a dozen or so times to distribute the spray.

with valve bases, insert/remove the valves a few times to clean the contacts.