Big Muff Mod needed - Searches have not gotten result

[Ape32]

Hi all -

I need a mod to get more volume out of a new NYC Big Muff. 

Story - years ago I homebrewed a big muff as a birthday present for my GF/bandmate (bass player).  It was recently stolen at a gig.

Since I have been too busy for FX build projects lately (full time work, moonlight live sound, band, etc) so we bought an NYC reissue. 

With volume maxxed it is still quieter (to the ear, while played live with our rock band) than bypassed.  The bass is an active G&L picked HARD  so maybe the muff never expected to match that.  My homebrew was louder at %30 of the vol. pot travel.

I have put extra SI diodes in line with the second clipping stage's stock ones for a total drop of .8v (and this seems to help a some).  I'm thinking that the last gain stage could be modded for more output.  As the last stage is a common emitter amplifier w/2.2 k as a emitter (to ground) resistor, would changing the value possibly give me more juice? 

Sorry for the dull question but I just can't seem to locate a solid mod for this (I really don't want the pedal to be too much of a science experiment as it is a gigging mainstay for us)

Thanks, Ape

[cd]

Stick a 25uf or higher electrolytic cap (negative end to ground) across that 2k2 resistor.

[Ape32]

Thanks CD -

So kinda like a fuzz face stage? 

[Mark Hammer]

The volume increase from a BMP is normally quite considerable, so if yours is less than bypass even when maxed then somethng is seriously wrong.  CD's suggestion to add the cap makes perfect sense for the reasons you assume, but I suspect the real focus of your efforts shuld be verifying that all parts are the values they ought to be and connected to where they ought to be, because your description of it just seems like something is wrong.  We're not talking modding a BMP here; we ought to be talking rehabilitating one.

[Ape32]

Thanks Mark -

Kinda nice to know that I build a better pedal that the auto-stuffers at EH.

I'll read some stripes, etc. Oh yeah cold joints, dead caps.......it's all coming back to me.... Kinda a burn to be fixing a new pedal !

The funny bit is that it sounds just fine and all the controls work as expected.

I wonder if a badly biased or dud transistor could be to blame - It's not like I can listen for distortion in the circuit 

[petemoore]

 I wonder if a badly biased or dud transistor could be to blame
  Certainly is possible, a check of the transistor voltages is what I'd do, I think it's a great idea to always check Q biases anyway...maybe it' could sound better misbiased, but I'm always checking it anyway.
  Audio probe is another way to check, each gain stage's output should sound louder than it's input, and the TC Section should have a signal loss to it.
  I forget what that last transistors function is, recovery IIRC, if so it too would boost. Been a while since I looked at a BMP schematic.

[Ape32]

Last stage is a recovery stage for the tone section - Per Mr. Orman it has an 8db gain typically to make up for the tone sections loss.

I'll check the bias and put a sine wave through to look for non-amplifying amps.

BTW the "double diode" trick got it useable - loud enough to work.  If I can't figure out what is wrong with it I may just replace the 1UF coupling caps w .1s (I did this on my homebrew as well and i liked it) and try some more tone network variations - perhaps the "mid dip" is hittng some key frequencies in her rig (in fact, duncan's calculator does seem to show that)

Thanks Again

[vanessa]

Stick a 25uf or higher electrolytic cap (negative end to ground) across that 2k2 resistor.

Does that give more clean volume or more fuzz gain?

[Mark Hammer]

It should increase the gain of the post-tone-control gain-recovery stage.  That extra gain and level boost should push the amp harder, but I doubt that it would result in more distortion internal to the BMP.

[SolderBoy]

We're not talking modding a BMP here; we ought to be talking rehabilitating one.

My 2c...

A stock BMP has a heap of gain.  Save yourself a lot of fuss, man.  Take it back to the shop and get a new one.

SB.

[Yun]

We're not talking modding a BMP here; we ought to be talking rehabilitating one.

My 2c...

A stock BMP has a heap of gain.  Save yourself a lot of fuss, man.  Take it back to the shop and get a new one.

SB.

i concur

[Ape32]

I should return it,  but of course, I have started cutting so there is the ethical consideration......

Of course they did fail QC so FKM.

[Yun]

I should return it,  but of course, I have started cutting so there is the ethical consideration......

Of course they did fail QC so FKM.

Hmmmm, i admire you're ethical reasoning, man.  Try e-mailing EH for support. 

I wouldn't return it either if i started "digging around in there".  As i said- i admire that....

Of course you can do a sustain punch mod that i posted (mainly removing all Q's emiters and jumering them to ground; EXCEPT for the Q after the tone circuit).  That will REALLY wake up any BMP. 

[A.S.P.]

see reply #1 & 2 here:,
for what happens with active guitars into fuzzes...