Marshall JMP-1 pre....

I'm hardly an authority on this, but; A preamp is traditionally converting a lower level signal into a line level. The JMP was not made to go into the front of another amp, It's supposed to go straight into a power amp. Especially on guitar amps, where the pre does a LOT of colouring to the signal.. you don't generally want it running thru 2 guitar pres. In the 80s apparently it was common to run your JMP or ADA pre into the fx return on a Marshall head... cause this fed right into the power amp

Ok, makes sense. I'm putting your comments in my evernote file on the marshall :)

I had one for a while in the early/mid90s. Incredible piece of kit... as long as you want just Marshall tones. I traded mine for a Mesa Boogie Triaxis which is much more versatile, and has been super-reliable - I've had reliabilities issues with Marshall equipment in the past. I'd definitely recommend the JMP-1 pre-amp, but after the Triaxis, I wouldn't go back to one.

I have Rocktron Piranha preamp that I use with convolution (I bypass its own cab sim). It is somewhat similar in principle to JMP-1. For cab sim I use LePou's LeCab 2 and mostly free impulses. I also have Scuffham Amp's S-Gear and with it and Ignite Amp's free Anvil I am very satisfied when it comes to overdriven/hi-gain sounds. If I remember correctly Anvil is PC only, tho. But it is my favourite free amp sim easily. I wouldn't say that Piranha is essential to me (after all I got as an indefinte loan from a friend) but with these three amps I got my blues/rock/metal amp sim needs covered. BTW S-Gear and Anvil sound as "real" as piranha with impulse cab sim IMHO. I have to say that for recording I prefer the hassle free system, I just couldn't be bothered to mic a real cab and blast it here. But it has to be said that I don't play live or with band. Sometimes I do use real amp and cab but it is for special occasions. I split the guitar signal with DI so that I get clean DI to Reaper but I also link that DI signal to real amp. This way I get the real feedback sound to that DI, without the amp itself. My lowly Epiphone Valve Jr is ok for this. Of course the monitoring sound isn't the final one in this case, but at least I got me some rockin' feedback screams :) When combined with real CryBaby wah, it is quite nice.