Errors with JMP-1 Amp model

RackAddict

RackAddict

Previous handle "Djenter"
After realizing that the JMP-1 amp model is basically my favorite model and starting to give me the best tones for my project, i have spotted some errors. Cranking the mid knob erroneously boosts the Output EQ's 125hz slider when i change the Eq to * band constant or variable.

But other than that this thing is unbelievable and the very tight solid state sounds that I was after have been achieved. Confirmed with a tech that this thing basically is solid state for the most part.
 
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I believe that is normal operation - for the JMP, the B,M,T are tied to output EQ sliders. Also - generally, changing any given slider in the EQ and then switching to a different EQ type without reset, yields another different slider showing adjustment in the 2nd EQ type selected.
 
sprint said:
I believe that is normal operation - for the JMP, the B,M,T are tied to output EQ sliders. Also - generally, changing any given slider in the EQ and then switching to a different EQ type without reset, yields another different slider showing adjustment in the 2nd EQ type selected.
Click to expand...

Hmm, thats strange. Why a repeat on the Output EQ page? Why not make them independent as all the other amp models are?
 
But if that were the case it would be more assigned to maybe the 500hz knob. I just dont see the point of having the two EQ sections linked as the point of the output EQ page is for more EQ versatility. I am sure this is an oversight. And the Treble is assigned to 250hz as another error. Thats midbass basically.
 
More errors, when flipping to the Ideal page, it just resets the knob to their defaults on this amp block for this model.
 
Ok I can confirm now that there is very serious problems here with this model. The presence is controlling the 500Hz slider! lol
 
Is this maybe just mimicking the design with the fixed tone stack / EQ on the actual jmp-1 preamp rack units? There was a change in the modelling a few FWs back, to get closer to the behaviour on the actual units. But I haven’t checked if anything was changed in the latest beta.
 
To confuse a little more, the passive Tonestack Controls (Ideal Page) are working only on the Clean1/2 Types, because they are only in the clean Signal path in the orginal JMP-1 (i looked in the JMP-1 Scematic...). This wasn't so clear for me to read in the discription (im not a native speaker)
So the OD Modell Type B/M/T Controls in the Editor Ideal Page do nothing.
 
If I remember correctly, the original JMPs have a B/M/T/P buttons that you would turn a knob to correspond to negative and positive numbers. You would actually press the bass button, rotate the value knob and it would either display positive or negative numbers as opposed to knobs that you would turn, like a traditional guitar amp. For example you would hit "bass", turn the value wheel and the display would read the 1,2,3 etc, which would be a positive bass boost, or -1,-2,-3 for a negative bass cut instead. There's no "putting the knobs at noon" paradigm with the JMPs.

This allowed pretty interesting patch changes so you could also adjust BMTP EQ via midi, in addition the the Clean/Dirty channels etc.

Volume and gain knobs also corresponded to 0-20 (If I remember correctly) values.
 
It actually works correctly now. On the real JMP-1 the BMT and P are actually just a 4 band EQ under the hood.
As a real JMP-1 owner/ user for decades, I am very pleased that Cliff got that right on a FW release more recently.
 
The errors you are describing are the way it was designed (to work in the Axe)
The B/M/T/P knobs control fixed output EQ sliders because that is the architecture of the actual JMP1.
Whether or not they are the correct frequencies (to your point, is treble actually 250hz?)...I don't know, I've never measured the frequency response of the JMP1's B/M/T/P knobs. I'd be willing to be that Fractal measured them properly though.

I was confused this update was first made in the Axe, but after a few uses...you get used to it.
 
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