Fractal Audio AMP models: Brit Pre and JMPre-1 (Marshall JMP-1)

yek

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* EDIT: Up-to-date information is available in Yek's Guide to the Fractal Audio Amplifier Models *
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Brit PRE and Brit JMPRE-1: based on Marshall JMP-1

The Marshall JMP-1 is a MIDI-controllable rack-mount tube preamp, based on the JMC 900, Marshall’s amp from the ‘90s. Bands such as Def Leppard, ZZ Top and Deftones are known for their use of the JMP-1. (Deftones now use the Axe-Fx II.)

Don’t confuse this with the current JMP1 “baby” Marshall.​

Fractal Audio’s first model of the JMP-1 was the Brit Pre. Cliff re-worked the JMP-1 modeling, resulting in the JMPre-1 models. The Brit Pre stayed on, because it is used by several prominent “A-list” artists.

The power amp section of the models is based on a typical Marshall 100 watts power amp of the ‘90s.

The JMP-1 has four modes: two Clean ones, and OD1 and OD2. Fractal Audio modeled both OD modes (JMPRE models).

OD1 is “a warm vintage drive reminiscent of Marshall Super Lead amps through to modern day Master Volumes". And: “Features the purity of distortion from the golden age of the plexi glass Super Leads. As the gain is increased you pass through degrees of distortion into a rich higher gain mode, with just the right nuances for the modern blues rock player. Vintage crunch, modern metal and fat blues lead sounds are all readily available.“

OD2 is “a tightly focused high gain drive which can be smooth or aggressive depending on the E.Q. and gain settings". And: “Tightly focused stunning high gain is what you will find in OD2. Modern and aggressive, smooth and fluid, the gain levels and singing tone of this channel will give you infinite sustain whilst retaining a pure toneful quality.”

The JMP-1 provides Gain, Bass, Middle, Treble and Presence controls, all adjusted through keys instead of rotary knobs. No Master Volume because it’s a preamp.

Cliff’s commenting on the Brit Pre model:

"The two channels have preset tone stacks. Then there is a digitally controlled 4-band graphic EQ which is the B/M/T and Presence. This technique gets around the problem of trying to digitally control a tone stack. The Triaxis uses LDRs in place of potentiometers. The Soldano X-99 uses motorized pots. Both techniques being expensive. So the JMP-1 uses a fixed tone stack and then a digitally controlled graphic EQ. The Axe-Fx model of the JMP-1 is "better" in the sense that the tone controls control the tone stack rather than a graphic EQ. You then have the separate graphic EQ to further tailor the sound. What I didn't do, and why people probably feel the model differs, is "normalize" the tone controls so that with B/M/T at noon the tone stacks match. On the Axe-Fx you might need to set the Bass to 3, Mid to 7, etc. to get the tone to match. I just used a standard Marshall tone stack whereas the JMP-1 uses a standard Marshall tone stack but the pots are replaced with fixed resistors but those values don't necessarily correspond to the pots at noon."​

Cliff’s commenting on the JMPre-1 models:

“The JMP-1 tone controls have more range than the actual preamp. The preamp has about +/- 8 dB for each tone control while the model has the standard +/- 12 dB."​

There is also a Bass Shift control on the JMP-1. Marshall:

“It’s a subtle low frequency character control. When selected it thickens the bottom end of the sound and tightens the playing feel. On clean selections it adds body and on overdrive it provides the extra low end “throb” so essential for heavy rock sound.”​

The two models with “BS” in the name were created with the Bass Shift function engaged on the real amp. I prefer the non-BS models, because I don’t like too much bass in my tone, but that’s a matter of personal preference of course.

IMHO the models of the JMP-1 are well balanced. At default values they already sound fine, although you may want to turn up the gain.

Because the JMP-1 is a preamp, there's no matching cabinet per se. Let your ears decide, or go with the traditional Marshall ones.





And here’s a recording by Guitarjon using the BRIT PRE and JMPRE-1 models:

 
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Don't you ever model the clean channels??

You're kidding right? There are so many clean amp models in the Axe and AX8.

Also: the clean channels of many channel-switching amps often are just copies of other amps of that manufacturer, or copies of Fender designs.
 
Not really actually. I think the clean clean british voiced models in the Ax are far apart. I know that 'nobody cares for clean anyway', but I play a lot of clean stuff. It is not like, I cannot find a good clean amp in the Ax, but there is already a plethora of drive models in the Ax, and I just notice that you often only model the drive channels of modern amps (especially Marshalls). I'd like more models, where you can turn the input gain past noon and still have a mostly clean sound.
 
Yeah - I already reduce input trim on most models, it helps, but I do not think, it is quite the same as an amp that is designed to stay clean.
 
I've always liked these models. If you haven't already, try them with the Palmer IR's posted to the forum some time ago.

I didn't realize the default tone stack settings did not match the real JMP-1 fixed tone stack either. Interesting stuff.
 
Don't you ever model the clean channels??

Smittefar - the clean channels on the JMP-1 are going for the clean sounds of Marshalls of yore, you already have a JTM 45 and a several Plexi's - their clean sounds are THE Marshall clean sound, so use these instead.
Trust me the clean JTM 45 or a clean Plexi has a beautiful sound, the (real) JMP-1 clean has a decent clean sound.
If you don't agree and lust for clean JMP-1 sounds then I'll give you a good price on my JMP-1 :)
 
Well, if we should exclude everything from the Axe that is really just another take on an old amp design, the amp model list, would go thin real quick - coincidentally, the jm45 would have to be removed ;)
Damn. You really want that JMP-1 clean channel, don't you? :D
 
Well, if we should exclude everything from the Axe that is really just another take on an old amp design, the amp model list, would go thin real quick - coincidentally, the jm45 would have to be removed ;)

I get your point, but it's not entirely correct.

While is true that the JTM45 was intended as a copy of the Fender Bassman (as there was a shortage of Bassman amps in the UK and Fender was unable to deliver enough to meet the UK demand), there where a few things that set the JTM 45 and the Bassman apart, a few key components were swapped due to supply reasons, the phase to the speakers was unintentionally reversed compared to the Bassman (because Jim Marshall was a drummer - I'm sure you get the joke), and the tubes used where UK or European tubes with a slightly different sound - so the JTM 45 does not react nor sound exactly like a Bassman, there is a clear lineage that is heard in the sound but also clear differences.

Anyway, Cliff decides which channels he chooses to model, and I can totally understand why he left out the clean channels of the JMP-1, not that they are bad, but
1) There are many other options for great clean tones, including great clean Marshall tones
2) Nobody (or at least not the vast, vast, vast majority of buyers did not) bought the JMP-1 for the clean tones, the JMP-1 made a name for itself for it's dirt tones and for being a 1U midi controlled Marshall preamp.
 
I do not really want that clean channel, but there are certainly clean channels, I wish were included. I get what you are saying @Rocket Brother , but to be fair, there are also differences between the JMP1 clean channel and a JTM45.
 
Hi Yek.

Great info again! It looks like you didn't include a link to the owner's manual this time. The link on the wiki page goes to the general Marshall support page but I couldn't find a copy of the manual there. The amparchives site has one.

The manual includes suggested channel, b/s, volume, gain and tone settings for some presets which might be helpful as a guide, particular to which channel and b/s setting to use, although thanks to the original post, I now know that tone control values don't line up :)
 
Sorry for my ignorance but...we have the Brit Pre in the Axe, but where is the JMPRE-1 ?Sorry but i don't understand.
 
;)Sorry , after my post, i went to my home studio and search ....effectively, i had only look about B....like Brit....
Pffff !!!!
So many Amp in the Axe.
 
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