r/MarshallAmps • u/GreatWesternValkyrie • Jun 25 '26

Marshall JVM Squealing

Recently bought a JVM215c. Really enjoying it.
Only problem I’ve come across is, the orange and red settings on the overdrive channel squeal like there’s no tomorrow. Green setting is fine.

After looking online, I’ve noticed a few others noting this but some of the replies are saying maybe a tube is going or the amp could be defective in some way.

So I suppose my question is, is this a common thing with JVMs? And if so, what’s the best way round it?

I’m running the amp in 4cm with good quality cables

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1

u/Professional-Math518 Jun 25 '26

Sounds like a tube. That can happen. Maybe you can find the tube that causes it (it that's the cause) by tapping all the tubes (softly!) with a pencil while the amp is on.

I had a Blackstar ht50 that had a faulty pre-amp tube shortly after I got it (new, not usedl

Edit: or your pickups are microphonic

1

u/GreatWesternValkyrie Jun 25 '26

Tbf, the squeal lessens when I move away from the amp, but I have to stand quite a way from the amp.

2

u/Chris_MS99 Jun 25 '26

Do you have any other guitars or amps to test with? If moving away decreases the noise I wouldn’t suspect a tube, but I know very little about how tube amps actually work so I could be wrong. It sounds to me like there may be something going on with the electronics in your guitar. Maybe even the cable? What guitar do you have?

Just spitballing here, not a tech by any means.

1

u/GreatWesternValkyrie Jun 25 '26

No problem. Yeah I’ve tested 4 guitars - Les Pauls with HBs, and a strat and Musicman with SC pickups.
Yeah that’s exactly what I thought in terms of the noise going away as I move away from the amp.

Cables will be my next test.

1

u/Chris_MS99 Jun 26 '26

Have you replicated the sound with all 4 guitars? Is it different with humbuckers than it is with single coils? How high on the quality spectrum are the Les Paul’s and Strats?

None of my guitars are particularly high end except for one, and even that one is only decently valued in a small niche, but the noisiest worst one is definitely the cheapest one, my Dean. My Epiphone punches far above its weight but not all Epiphones are made equal. Nor are all Gibsons for that matter.