How to mix Marshall & Fender preamps ? (Modding a Bandmaster Reverb)

[Iplayloud]

Bandmaster Reverbs are going for dirt cheap lately, I got my second one for 350$. It's rather cheap for a PTP vintage amp. I agree it has a smaller OT and low plate voltage but I plan on putting a GZ34 (vs 5U4) to raise the voltage (recapping as well so they don't blow up). And I was hoping to use the normal channel and tremolo tubes to make a Marshall Plexi style preamp. I was just wondering how to mix both together. The Fender circuit is already mixed with 220k resistors so should I just hook the treble wiper of the Marshall preamp circuit to the 220k mixing resistor ?

[jrfrond]

You can heat up either channel (I suggest the "Normal" channel) in such a way as to do a decent impression of a Marshall Plexi, with bastardizing the entire amp and still enjoying the functionality of the trem and 'verb. I do it all the time to these and other Fender 2ch. amps du jour ad it works great, plus is totally reversible.

[imaradiostar]

And how does one do that? Specifically, what do you change?

Just curious- I've never much liked the Fender mid scoop combined with pedals.

jamie

[Iplayloud]

Indeed I may regret bastardizing the amp, but I really want a JTM-45 clone and think in financial terms, how much would it cost ordering a head box, transformers, take the time to assemble. With the Bandmaster I'm a few components away and if I figure how to mix the channels... Bingo.
To Imaradiostar, a good place to start would be the EQ. Download the Tone Stack Calculator here: TSC
It's surprizing how the Fender EQ dips the mids really bad. Check the James style EQ it's really flat and has the same input impedence as Fender. Never tried it though...

[imaradiostar]

Thanks for the reply- I use TSC and Spice modeling for all my EQ designs just so I can "see" what I'm hearing. Even with EQ mods I'm not crazy about the Fender design so I was curious what John had in mind.

You could always do something blasphemous- use an LND 150 for the "normal" channel first stage and wire the 12ax7 for that channel as a marshall style 2nd gain stage and cathode follower. You could even bootstrap it for more gain if that's what you're into.

jamie