l100 Organ amp to guitar amp Question.

[57champ]

Hey, I've got a amp from a Hammond L100 organ that I'm currently using as a guitar amp, here's a link to the schematic, http://www.captain-foldback.com/Hammond_sub/schematics/L100_early.gif. The Amp I'm using is the reverb and power amplifier in the upper right hand corner. It is a good sounding tube amp but its a bit too bass heavy for me, anyone have any idea how I could boost the treble and mids a bit in this thing. I am going to do a full conversion to a spitfire like amp at some point but for now I just want a bit more treble. Any help would be appreciated.

[a soBer Newt]

My first thought would be to have a simple high pass filter to get rid of any low end form the guitar. Its like mixing if you need more top end try removing what is going on at the bottom.

[runmikeyrun]

Simplest way would be to put an eq pedal in front of the input.  Failing that you could put in smaller cathode bypass caps on the 12ax7s, c301 and c308.  Simpler yet how about an small input cap before the first 12ax7, say 0.1uF?  I don't see any input cap at that.  You could also put an output cap off the second gain stage of the 1st 12ax7 to roll off bass before it hits the reverb unit.  There are many things to try. 

Remember even though your amp is tube, many basic guitar/effect rules still apply.   

Don't forget to check your output tube bias and adjust a needed.  It could also be your output tubes giving you too much low end- I have a converted 50's Conn organ power amp that sounded flat, dull, and lifeless with Russian 5881s... I put some old Ruby EL34 long plates in there and the amp came to life.

You're going to have a lot of fun with your amp, I sure did.

[runmikeyrun]

Oh yeah, you could also wire in a tone section but you may lose a lot of gain after it... I tried a baxandall on mine and it sucked a ton of balls out of the amp. 

Also a note on replacing caps- observe voltage ratings!!  Measure voltage on your cathode and plate and get caps rated for at least 50% more voltage.