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I too exchanged currency for goods

2K views 19 replies 11 participants last post by  maliciousteve 
#1 ·
#9 ·
:lol: Couldn't be anything else really given the bottom edge



So, my rig is getting there. I did end up getting rid of my Rectifier as it was collecting dust since i modded my JVM (i honestly never saw myself sacking off rectifiers in favour for a Marshall, but here we are...). I felt the money would be better spent on gear I actually need and that would be useful to have. Get a really functional and awesome rig once and for all, rather than tap-dance my way through a set (hence the GSP1101 and foot controller, etc)



Just missing a 1U power amp now, which is on its way (I snagged a filthy cheap Rocktron Velocity 300, as it's in need of repair)

For live use I'm only intending to use the GSP1101 for FX, with the JVM as my amp. The JMP-1 + Rocktron will be there simply as a back-up amplifier, should the JVM shit the bed.

But for recording, the JMP-1 into the JVM's power amp is SUCH a sick lead tone.
Check it:

https://www.dropbox.com/s/v1d6vzo1n1zdf8l/JMP-1.mp3?raw=1
https://www.dropbox.com/s/v1d6vzo1n1zdf8l/JMP-1.mp3?dl=0

Rhythms are JVM, solo is JMP-1 into the JVM's power amp.

The JMP-1 on the whole is really nothing special. It's basically a rack-mounted 8100. Very similar tone, feel, and circuit. It was also released the same year, so it's definitely got that Valvestate series DNA. I've had a ton of early 90's Valvestate stuff, both personally and from customers to repair, and it had that instantly recognisable feel and tone.

Contrary to most other Marshalls though (and amps in general) OD1 is a more aggressive and percussive voiced overdrive channel, where as OD2 is the more squishy and mid-rangey, although definitely with more gain on tap (OD1 still has more than enough for a good metal rhythm tone though, especially when boosted).

Even when using the JVM's power amp, flicking between the JMP-1, and then going back through the front of the JVM (so using the JVM wholesale), you can really feel/hear that this is a very static, solid state, kinda meh sounding amp, and the JVM eats it alive with that all-valve roar and grain. But, that's not to say the tones aren't awesome, and that it's not a lot of fun. Perfect for leads for that reason. It's got that 80's tight squish to it, which sits it in a mix (or rather, lets it sit on TOP of a mix, like a good solo should!)
 
#11 ·
Someone must have fucked with my JMP-1 before I got it :lol:

I find the opposite for the OD channels, OD2 is more aggressive, OD1 is a bassy, squishy mess. I finally finished with mine, replaced R124 with a 10K cathode resistor and a 1uf bypass cap, I can actually run the gain on 15-16 now and still get some good pinch harmonics.
 
#15 ·
Well being a hack myself and not understanding too much other than high resistance on the cathode making it clip more I couldn't tell you :lol: BTW, don't try a 39k on the cathode, that isn't usable. At all :lol:

The way I see it, bumping it up to 10k basically takes it to Marshall spec, I mean that's what they use for a cathode resistor on their high gain amps :lol: Maybe my diodes are getting old and fucked up, since that's where a lot of the clipping and initial gain is supposed to come from in the JMP. Then again, I think I recall seeing in a schematic and reading that's the way a lot of Marshalls are.
 
#16 ·
Well being a hack myself and not understanding too much other than high resistance on the cathode making it clip more I couldn't tell you
BTW, don't try a 39k on the cathode, that isn't usable. At all


The way I see it, bumping it up to 10k basically takes it to Marshall spec, I mean that's what they use for a cathode resistor on their high gain amps
Maybe my diodes are getting old and fucked up, since that's where a lot of the clipping and initial gain is supposed to come from in the JMP. Then again, I think I recall seeing in a schematic and reading that's the way a lot of Marshalls are.
A lot of the 90s ones used diode clipping and well all those jcm800s on recordings did too or extra gain stages added which is why a lot of people are disappointed when they try them and they don't sound how they imagined.

Long time since I've seen a jmp1 schematic but I seem to remember an ic being used for some of the gain too so that might be worth looking into.
 
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