Varitone and Mini-Booster to help band mate's muddy tone?

Started by Isaiah, September 30, 2011, 06:52:43 AM

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Isaiah

Hi,

I'm building a pedal for one of my guitarists.
He most plays with the neck humbucker in his Telecaster and his tone can get muddy very quickly.
Especially compared to the other guitarists, who choose a less overdriven sound, play fewer chords/more lead, and use the volume control on their guitars all the time.

I don't won't to build something that sounds like it thins the tone too drastically, as he might never use it.
Equally, I don't want to build something that will further distort the sound much.

So, after some breadboarding (admittedly with my singlecoil-equipped Mustang, into a Tascam 4-Track ::) ), I'm gravitating towards:
Varitone passive notch EQ (with bypass and maybe a deoth control) into an Mini-Booster.

The Mini-Booster is pretty standard.
Except:
JFETs are 2N5457
C2 is 1uF (could be 0.1uF, to cut more bass)
C6 is removed
R5 is replaced with a 10K pot and 1K resistor wired in series to act as a gain control.



I suppose the Mini-Booster, as described above, could be boxed by itself (maybe with C3 reduced to, say, 0.022uF or 0.047uf ), to work as a treble boost.
But would that be too trebly and end up being cranked, pushing the tone further into overdrive?

I guess what I like about the Varitone is that it cuts notches, it doesn't act like a HPF, and it cuts the volume a little before it reaches the Mini-Booster.

Any thoughts on this please?

Cheers!

Isaiah

Ignoring the Varitone for a moment, I just tried a 5M resistor between the drain and gate of Q2 for some negative feedback.
It works pretty well to reduce distortion and also cuts bass a bit too (good when C2 is 1uF).

Mark Hammer

I've put together a couple of things exactly like this, except that they were a single JFET STratoblaster clone and an Anderton EPFM Passive tone control, using a 12-position rotary switch.  Worked great.  Including the booster is a requisite, because the LCR mid-scoop results in a fair mount of passive loss that needs to be compensated for.  A gain or level pot is also a requisite, since the amount of passive loss will vary, depending on where the scoop is situated and how broad it is.

MikeH

Quote from: Isaiah on September 30, 2011, 06:52:43 AM
Equally, I don't want to build something that will further distort the sound much.

I've always though of the mini booster as more of an OD than a boost, because it gets quite dirty.  I'd think the AMZ mosfet boost would be better in this application.
"Sounds like a Fab Metal to me." -DougH

Isaiah

Thanks for the replies!
I actually tried a MOSFET booster shortly after posting, and you're right, it's much better for my needs!

The MOSFET booster circuit I used is very similar to the SHO, but with 2K7 resistors at the drain and source.
Gain control was implemented using a cap and pot like the AMZ MOSFET Booster.
By removing the gain control, I found I can instead implement a crude graphic EQ.

I tried using just two bands, and it was pretty interesting, though the bandwidth of each peak/notch sounds quite broad. Any simple ideas for making them narrower?
I was using the primary coil of a 10K:10K transformer, if that helps.

Cheers!