#1
I'm still fighting to find a clean tone on my Marshall JCM900. I have an overdrive tone that I love, exactly what I need, but since it's only a single channel (I think) amp I can't get it to clean up nicely.
INB4 volume knob!
I've tried rolling back the volume / using my EQ pedal (level slider) / using my EQ pedal with the volume knob. But every time I do I get a massive drop in volume, which when I'm gigging is going to be a problem. Also, when using the volume knob my cleans get quite brittle and muddy.

What solutions are there I could look for? I can't think of anything I can do at the moment.
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

#2
Wow, running out of headroom on a jcm 900?!?!

That's a 100 watt amp there, it should be shaking the walls!

You DO have a clean channel, make sure it's on that, and dime the master volume, keeping gain at about 2 or 3.

PerMarshallEdit:

...Channel A has been voiced for a sparkling clean on lower gain settings, building up to a raunchy crunch when driven hard. Channel B takes off from where channel A finishes with acute use of the Gain and EQ controls...
Last edited by Rutch at Sep 30, 2009,
#3
Quote by Rutch
Wow, running out of headroom on a jcm 900?!?!

That's a 100 watt amp there, it should be shaking the walls!

You DO have a clean channel, make sure it's on that, and dime the master volume, keeping gain at about 2 or 3.

PerMarshallEdit:


Thank you sir! I have been looking to find that bit of marshall info for ages. Looks like I need me a foot switch.
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

#4
You thought your amp was single channel but its two? I somehow doubt that you can only switch channels with a footswitch... But then again the whole JCM series is a mystery to me.
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#5
Quote by tubetime86
You thought your amp was single channel but its two? I somehow doubt that you can only switch channels with a footswitch... But then again the whole JCM series is a mystery to me.


Mystery to me too, I think that info might be about a different amp. There's no other way to switch channels and it's always set to channel B. I'm wondering if it might be a boost or something built in. But then that means that it was very little headroom. Which is very odd for a 100W the preamp starts to break up around 8/9o'clock on the preamp volume knob
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

#6
Look at the Manual

The button to switch from Channel A to B is between the Footswitch Jack, and the Channel B Volume

2001 Ernie Ball Music Man Axis Super Sport
2001 MIM Standard Strat
Peavey Classic 30 112 Combo.
My Gear
#7
The Manual for my amp says that it is just a foot switchable boost for rhythm and lead playing. Apparently I've been running my amp at 50W as well. Would that make much difference to the headroom for cleans?

If that's all right. Back to my original question what can I do to get myself a clean tone from this amp?
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

#8
That manual shows the same button between footswitch jack and Channel B volume.

Perhaps pictures of your actual amp front panel....

Which amp do you actually have, 100W HEAD or COMBO, 50W Head or Combo?
Is it the MasterVolume model, or Dual Reverb Model..

Either way, in the manual you posted, they ALL have a Channel B button, between footswitch jack and Channel B volume.

2001 Ernie Ball Music Man Axis Super Sport
2001 MIM Standard Strat
Peavey Classic 30 112 Combo.
My Gear
#9
Pic of my amp's front panel:


It's the Hi Gain MV combo.

There's no channel switch, just an LED and a footswitch jack

EDIT: wrong thing on clipboard
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

Last edited by SimplyBen at Sep 30, 2009,
#10
Wow, Mk III, that's a pretty cool amp..

Backing off your guitar's volume should work just fine. You shouldn't get a huge drop in apparent volume unless you want a pristine clean sound and you're rolling the volume back too far, if you have the gain high then you're just going to get a clean with a bit of hair on it and you'll just have to be content with that. Otherwise, you can try varying your pick attack to be a little bit softer as well. I usually roll my volume back to the just inbetween point where if you pick hard, then you'll get some nice break up and you'll get lightly distorted chords if you strum hard, but if you pick softer and strum softer then you'll get a cleaner sound.

A lot of this also depends on the pickups you have in your guitar as well as the pots and wiring. If you're using a les paul style guitar then your guitar is probably wired like this...
Which is the reason why your tone is getting bassy and muddy when you roll back the volume control. There are a lot of easy ways to fix this, and I'm sure a lot of people will tell you to install a treble bleed, but in my opinion, re-wiring to the '50s spec is easier and sounds better.
There are some benefits to having the modern style wiring, but if you need, it changes how the controls interact with each other, and if you want to keep that aspect, then you can try a treble bleed, but imo, a treble bleed sounds thin and sterile when you roll the volume down, with the '50s style wiring you'll maintain the brightness in your tone, clear things up and it will sound more... (for lack of a better word) natural. Just my opinion though, YMMV. It will also help to stick higher quality pots and caps in there as well, though that requires you spend money.
#11
Wow, I stand corrected.

Maybe that's why that model was discontinued.
That's just terrible that you can only switch channels with a footswitch....TERRIBLE!!!!

2001 Ernie Ball Music Man Axis Super Sport
2001 MIM Standard Strat
Peavey Classic 30 112 Combo.
My Gear
#12
Quote by jonmo1
Wow, I stand corrected.

Maybe that's why that model was discontinued.
That's just terrible that you can only switch channels with a footswitch....TERRIBLE!!!!


Argh that is very annoying oh well, I love the amp so I'll work around it. I think Al's wiring tip might help me a bit, I'll try that before spending money on it since I'm just running an Epi G400 so swapping pots and things seems a bit much right now.

EDIT: Other than changing my wiring and possibly pups and stuff is there anything else I can do?
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey

Last edited by SimplyBen at Sep 30, 2009,
#13
I'd change the wiring first, it's really the easiest option. It takes like... 5 minutes.
#14
Get the footswitch.
I see several on Ebay for about $20

2001 Ernie Ball Music Man Axis Super Sport
2001 MIM Standard Strat
Peavey Classic 30 112 Combo.
My Gear
#15
Right I'm gunna try the wiring. Only trouble is I'm confused (very new to electronics and not good with working stuff out) gotta pic of my guitar to help.


What do I need to change on there?
(I've had a long day so if it's obvious please bare with me)
LesPaul
Pedals
OrangeRocker30
My band
PBT Native: Resident Graphics Monkey