Modding the XO Little Big Muff (newer version) for Tone bypass?

[scott_v]

Need some advice on modding an XO Little Bigg Muff for "tone bypass".

It is noted in KitRae's Big Muff site that this is the same circuit as the Ver.9 NYC Big Muff Pi (reissue) where in that version of the muff that the well known tone bypass mod is lifting C8 & R5 from ground) which i have done before. However, on the little big muff  I see a very different value for C8, 2.2 uF???  I've not seen this value being used for this cap in any other version of the big muff...  Since this is the low pass filter for the tone stack, would reducing C8 from this 2.2 uF to 1.0 have any affect? or even .01 uF (as on most muffs)? My understanding is reducing this cap my reduce the treble (but also in conjunction with increasing R8).

I've also read in some other forum (sorry I forget which now) that only C8 needs to be lifted to get tone bypass and R5 can be left alone?  I'd like to consider doing this on the little big muff as I'd rather mess with as few of these SMD components in this circuit as possible.

Any thoughts?

Here are some links to the circuit board of the little big muff (from KitRae's site):

http://www.kitrae.net/music/IMG_4031.jpg
http://www.kitrae.net/music/IMG_4033.jpg

[scott_v]

Okay tried this and wish i did it differently...  Lifting C8 basically killed the sound, I should've traced this tone circuit path around first before just beginning.  What's happening is C8 goes to R8 first and then to ground... thats not the case for the NYC Big Muff.  Also R5 goes to C15 first then to ground... I think I now have something that sounds like tone bypass whcih is basically taking C of Q3 to ground (bypassing C8/R8), there was a kick up in volume and mids but the treble is diminished.  I'm now wondering if the same needs to be done for R5/C15?

[scott_v]

Realized that a tone bypass was not easy on this particular circuit, so decided to go with the mids mod (via kitbuilder webpage) and it is in keeping the tone pot... changed C8 from the weird high capcitor value of 2.2uF (according to Duncan tone stack caluculator this provides a very very scooped mid tone! and sounds like it because in a band setting my guitar and bass disappears) to a .0047uF (didn't have a .004uF) so along with C9 being .0039uF and R5 & R8 being equal (changed from 27k to 33k for both, but could've just kept them stock) it only gives a slight mid scoop, and it sounds more flattened... will give this a try in my band to see it cuts through now, if i want abit more mid scoop i could change C8 to .01uF which then gets you in the range of a "triangle" or a "ramshead".