Mid mod for BIG MUFF PI

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Mid mod for BIG MUFF PI

Postby Mbas974 » 31 Aug 2013, 21:22

Having bult a V2 "73" RAMS HEAD BIG MUFF PI

http://www.bigmuffpage.com/images/schem ... _schem.jpg

I'd like change it in order to have a sound rich of mids but without low-frequency rumbling,

any idea (ideally working only on tonestack and last trx stage) ?

THNKS in advance.
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Re: Mid mod for BIG MUFF PI

Postby phatt » 01 Sep 2013, 15:13

Try lowering the value of C3 for less bass,, in fact you may want to try altering the value of the other interstage coupling caps as well before you arrive at a good result.
Oh BTW there is no mojo value that is perfect as the result is very much dependent on factors *outside* of the circuit.
Meaning your PU's may output more bass than others and your Amp may have more bass than others.
So if you are fine tuning remember it may not work so well with other equipment.
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Re: Mid mod for BIG MUFF PI

Postby Nocentelli » 01 Sep 2013, 16:13

You can alter the mid content, e.g. removing the slight midscoop to give flat or boosted mids, and/or shifting the position of the mid scoop/boost, simply by altering the two caps and/or resistors in the tonestack. If you download (free) Duncans tonestack simulator from: http://www.duncanamps.com/tsc/ you can play about with values to get an idea of the effect it will have on the sweep. It's only a simulation, but it gives you an idea of how each component affects the sound.

There is a also good guide to BMP tonestack mods (as well as just about every other BMP mod you could care to mention) at http://rkerkhof.ruhosting.nl/Taas/Mods/Big%20Muff.htm

If you don't mind adding another pot, you can add a "presence" control (essentially replacing one fixed resistor in the tonestack with a pot) that allows you to dial in mid scoop, mid boost and every shade in between: it can be found at http://www.muzique.com/lab/tone3.htm

If you don't fancy adding this as another pot, you could always build a little daughterboard to hold it with a preset trimmer to dial in exactly the mid sound you want, set and forget.
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Re: Mid mod for BIG MUFF PI

Postby Mbas974 » 02 Sep 2013, 20:52

Thanks both of you, I'll try and post the result. :thumbsup
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Re: Mid mod for BIG MUFF PI

Postby MrSparkle666 » 03 Sep 2013, 12:22

The mids scooped sound is what makes the big Big Muff sound like a Big Muff. Honestly, If you get rid of the mids scoop, it starts to sounds like every other distortion pedal (I've tried). So maybe you want something else.

Anyway, to answer your question, the boomy bass and mid scooped character mostly from the way the tone stack is designed. To get rid of that characteristic, I would recommend simply ripping out the tone stack and replacing it with a different design, such as the tone stack from a proco RAT.
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Re: Mid mod for BIG MUFF PI

Postby bato001 » 03 Sep 2013, 12:44

The easiest way to get rid of the scooped mids on the BMP is bypass the tonestack. You get a huge increase in volume as well.
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Re: Mid mod for BIG MUFF PI

Postby Nocentelli » 03 Sep 2013, 18:54

bato001 wrote:The easiest way to get rid of the scooped mids on the BMP is bypass the tonestack. You get a huge increase in volume as well.


You can switch a 150k-ish series resistor for the tonestack if you want to keep the level about the same. I found bypassing the tonestack altogether made mine a bit hissy, I think I stuck a small cap (like 1n/470p) to ground after the 150k padding resistor.
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Re: Mid mod for BIG MUFF PI

Postby pinkjimiphoton » 17 Mar 2014, 21:12

i don't like the bypassed tone stack, makes it too big and woofy, loses its character and definition.

that said, BIG fan of the mid pot add on. works wonders on how the muff sits in a mix. i like a larger value (250k-1m) than the 100k usually suggested.
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