Woolly guitar sound

[frosty55]

Are the tubes at fault when getting a "woolly" sound when playing low chords like E and F?
I play a Les Paul through a Marshall JMP Mk.2 100watt head and was expecting a lot more "crunch" than what I am getting.
Any help appreciated thanks.

[Steve Conner]

Need to know more... What are the controls on the amp set to, what are the controls on your guitar set to, which pickup are you using (neck vs bridge), what sort of speaker are you using, did you replace your strings recently, etc.

Have you tried turning the bass and midrange down and the treble right up?

Which input are you using? There should be four input sockets on a JMP, two of them give a bassy sound and the other two give a trebly sound.

[frosty55]

The Marshall has all controls flat.
I use the bridge pick up on the Les Paul (Seymour Duncan SH-5).
The drivers in the cab are brand new Celestion V30s.
The strings are new.
There are two inputs on my JMP. High and Low. I use the Low.

[pdf64]

Are you using a proper speaker lead (ie not an instrument lead)?
What output tubes are in the amp?
How much use have they had?#
Do you mean that the controls are flat out, on full, or that they're set (hifi type) flat, at a middle possition?

[frosty55]

Yes, I am using the proper lead. Dont know anything about the tubes.
I always have the EQ on the amp half-way. Flat.
I have heard on another site that I should replace all the "Electrolytic caps", whatever they are.

[pdf64]

The tone controls on a guitar amp are nothing like a hifi - setting them halfway is nowhere near a flat response. Some exceptions, such as some Ampegs.
So the Vol controls (ie gain and master) are set halfway also?
What markings are on the output tubes (eg sovtek 5881)?
Have you any idea how old the amp is?
How long have you had it?
Have the tubes ever been replaced?
Roughly how much have you used it, since the tubes were replaced?
Did it used to sound better?

[frosty55]

Just got the amp. Its been dated as a 1980 Marshall JMP mk.2
The valves are ec883 and EL34.

[Alex R]

Hey that 'low' input on the master volume Marshalls is generally so low-gain as to be useless. I would say that's your problem - there's never going to be any crunch on that channel. Plug into the other one!

[Gtr_tech]

Yea....the low input actually bypasses the first gain stage.....not the way to go unless some kind of near line level output effect is used in front of it. If you find it too dirty, just reduce the preamp drive setting.