Marshall 5213 Found, noisy, but works!

[plaintop]

A buddy of mine found this amp at goodwill for $30. Initially, it had no volume or sound, well it had a weird noisy wavy sound. I blew out all of the pots and it brought it back to life, the gain channel and everything work great. It is however still noisy while not being played. Any ideas what to try next? Caps? thanks, my first post!

[plaintop]

There is a mild hum and static to be more specific about the noise.

[Roly]

Hi plaintop, welcome.


Great score, well done.

Does the noise respond to the controls, volume and tone?

Meanwhile...

More cleaning.

If it has Fx Send and Fx Return try giving these a good clean with contact cleaner or metho.

If it's dirty, clean the circuit boards both sides.

[plaintop]

Hi, and thanks. No, it seems to be just always noisy if that makes sense. It's not really apart of the signal.

[Roly]

"Not changed" by volume controls points to the output stage.

Can you do a short sound clip?

And maybe a pic or two so we know what we are talking about?

[plaintop]

I cant seem to get this video online. It just makes pops and swirls and hiss with a slight hum in the background. Any help appreciated. I can maybe email the video. thanks!

[Roly]

Forget caps for the moment, they don't give nearly as much trouble as people seem to think.

Just "blowing out" the pots is not sufficient.  They need liquid contact cleaner or metho.

If the amp has an Fx Send Return loop (a.k.a. Pre Out/Main In) then try plugging a known good lead into each and see if that makes a difference; if so then these sockets also need a good wash/scrub.

[J M Fahey]

Upload your video to youtube and post the "share" link here.

[phatt]

If the hum, buzz, hiss cannot be heard when playing at medium to loud volume then I'd guess this is normal as a lot of hi gain amplifiers are quite hissy especially big 100 watt marshalls which is likely what you have.

A chap I know has a similar Marshall Amp and it is very noisy but he plays loud so you don't notice the buzz but if you are in a small room low volume then it would be annoying.
Those type amps are a pain at low levels

You may just have to accept these amps are prone to this issue.
On the other hand if the noise is extreme there maybe a problem.
Just a sound clip would give us an idea of how bad and if there are deeper issues.
Phil.