For this article some more updates on what can be achieved with the Marshall JCM 900 SL-X amplifier.
What I will mention in this article is not only relevant to the JCM 900, but to almost any Marshall amplifier, as most Marshalls amps share a similar tonal character.
In the last article on this blog I mentioned the use of the Pro Co Rat and the DOD FX87. Using both of these pedals creates a kind of tubefeel including tubesag when you dig in your strings.
To get a Fender kind of sound out of your Marshall: Turn down the preampcontrols as much as possible, work with your volume, open it up as far as you want to get any volume. The amp is now ready to accept pedals, the characteristic Marshall sound is gone, but not to worry, amp will sound very dynamic when using any kind of booster pedal.
I worked with the Pro Co Rat as booster, and mainly used the filter of the pedal and placed the volume of the Rat at unity level. The DOD FX87 adds a bit of shine on the overal sound. The sag feel I mentioned before is mainly created by the Rat, but using only the Rat or the DOD, and the sag is a lot less noticable. Using both these pedals creates the magic touch. Use tonecontrols on the amp to any setting you like. Place a compressor before the Rat, and a EQ after the DOD if you like.
No Rat and DOD FX87?
Don’t worry, all you need is a booster and something which can change the tone, next you may need some kind of exhiter.
What about if you do not use any pedals at all? Will you still get that sound? Unlikely, because the Marshall will start to sound very tiny and it will need some kind of boost and tonal change, to give the overal sound more body.
There are plenty of ways to do it as long as you can create a boost and a change in tonal character you will be there.
I have tried this set-up with smaller Marshalls, and very similar results as to what I mentioned here before.
Fender Twin Versus Marshall:
Some of you may wonder why on earth would someone bother changing a good sounding Marshall into something tiny as this? Well that is all up to you, I myself like the idea of getting as much out of one amp as I can, and backing down on the Preamp does give you more options to change to tonal character of the amp drastically.
Try similar approach with a Fender Twin and you will not succeed: It is very hard to overdrive a Twin with its preamp. The amp will give you clean, putting up any of its volumecontrols will make the amp louder but not change its tonal character. Marshall amps, on the other hand, are more versatile in this respect: Most of the tone of the amp is created by putting the pre-amp up. Backing down on pre-amp volume will make a change in tone, also the amp will take on the character of whatever preamp pedal you put infront of it.
Extras on the JCM 900 SL-X:
The SL-X does contain a few extras I have not mentioned before in any of my previous articles about this amp: The Low/High volume switch as the back of the amp, and the Effectsloop, also located at the back of the amp.
The Low/High switch acts as a Low/High input on any older amp. Does this cut the wattage down? Well, I feel using the High, will boost the bright sound, and does make the overal sound louder. Older Marshalls used to have bright inputs and normal inputs. These days you do not find them any more, but by adding a switch of this kind Marshall does give a nod to its past.
The Effects loop is useful for various applications: Obviously just as a effects loop, but you can also use the loop as a booster for the poweramp: Plug in a patchcable in the return (or the send) and it will add more boost to the amp. Make sure you open up the volumescrew of the Effects Loop! Does the amp change its tone by adding a patchcable to its in-or output? No, it will just add more volume to the poweramp, depending on how far you have opened up the screw for the volume on the Effectsloop. You can use this approach if you need more volume to your overal tone, and it will work.
Enjoy for now, and hope to catch you soon again.