Easy mid cut for single tone knob amps

Discussion in 'Shock Brother's DIY Amps' started by jsnwhite619, May 6, 2021.

  1. jsnwhite619

    jsnwhite619 Friend of Leo's

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    I stumbled upon a mod on an old amp forum last weekend that I've never seen mentioned before. The post was from 2009, and it didn't even get a comment or mention in the entire thread. But it works!

    It's a fixed mid scoop for a single tone knob amp. I tried it in my College Dropout amp (my Harvard based circuit) and it does wonders for tightening up a cranked Les Paul. It can use some tweaking to fine tune it, and I think it does cause a little drop in output - but it's cutting mids in a Tweed amp, so I guess it's to be expected.

    At the first V1 coupling capacitor that was .022uf I made this change:
    • .1uf followed by a 100k resistor, and bypass the resistor with a 250pf capacitor
    I played with a few higher & lower bypass caps there, but not the resistor value. I think a lower value there would be better, but I haven't experimented there yet. But, I like what I'm hearing so far. This amp was already pretty smooth with some of the common mods, but I can't believe how well the humbuckers stayed together. I think the resistor value is where the balance between Tweed roar and cleaner, cutting overdrive will be found.

    Just a cell clip here, but my Les Paul with Pearly Gates PU's through my Pro Jr cab with a Legend 1058. Amp on 12. 5y3, 2x 6v6, 2x 12ax7

     
  2. cyclopean

    cyclopean Poster Extraordinaire

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    This is cool, but I’d also like to point out that if you don’t want to open up your amp and possibly shock yourself, eq pedals are pretty cheap these days.
     
  3. RomanS

    RomanS Poster Extraordinaire

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    I added a Framus mid control - https://robrobinette.com/Generic_Tube_Amp_Mods.htm#Framus_Mid_Control - to the normal channel of my modded 5E3 (after splitting the channels). Works really well for the way I use that am: Tele with edge of break-up tone through the bright channel, lap steel with a cleaner, more mid-scooped tone through the normal channel. The mid pot does rob a lot of gain, though, to match volumes, when I have the bright channel at around 3 on the dial, I have to set the normal one to about 7-8 (with the mid pot turned halfway down).
     
  4. jsnwhite619

    jsnwhite619 Friend of Leo's

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    That's not how I roll....;) This worked for $1.50

    I tried that before, and yes, it was way too much of a cut for me. This lost some volume, but I was still louder than I ever would set it if I was playing with a group.
     
    James Knox and RomanS like this.
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