Big Muff Gain Mod Question (limiting resistor)

[blueduck577]

Schematic: http://img262.imageshack.us/my.php?image=bigmuffusareissue3fd.png

Since replacing the schottky diodes in my NYC muff with silicon diodes, I definitely got a more compressed sound.  Problem is now, the pedal seems to have less gain.  I've been looking into different mods to remedy this problem so I don't have to run a boost into the muff.

I was reading http://www.student.ru.nl/r.kerkhof/Taas/Mods/Big%20Muff.htm.  Near the top it mentions the resistor mod, involves changing the values of R19 and R12 on the schematic to make the unit more gainy.  The site says to enlarge them, but my (limited) knowledge of pedal modding leads me to believe this is a typo.  Shouldn't I reduce/jump the resistors to give the unit more gain?

Side note: I've also considered building a small boost on veroboard and installing it in the case of the muff.  I've built an LPB-1 and AMZ Mosfet boost, but both suffered from terrible hum and buzzing.  Any insight into this?  I'm running off of the AC adaptor, and both circuits hummed like hell both inside and outside the muff, connected to the muff circuit or not.

[manson]

I'm sure it's a typo. Larger resistors there will result in less gain. You could try replacing the stock (8k2?) ones with something like 4k7.

[petemoore]

   Schematic: http://img262.imageshack.us/my.php?image=bigmuffusareissue3fd.png
  First let me say kudos for posting a schematic !

Since replacing the schottky diodes in my NYC muff with silicon diodes, I definitely got a more compressed sound.  Problem is now, the pedal seems to have less gain.  I've been looking into different mods to remedy this problem so I don't have to run a boost into the muff.
  Read 'foreward threshold'...I didn't, the data sheet on the schottky's should have the FT, and that is what determines at what point [voltage swing wise] the clipping begins...how 'hard', how much compression, which also dictates how much signal is attenuated = how much is let out after the diodes clipp off the wave peaks.

I was reading http://www.student.ru.nl/r.kerkhof/Taas/Mods/Big%20Muff.htm.  Near the top it mentions the resistor mod, involves changing the values of R19 and R12 on the schematic to make the unit more gainy.  The site says to enlarge them, but my (limited) knowledge of pedal modding leads me to believe this is a typo.  Shouldn't I reduce/jump the resistors to give the unit more gain?
  R12 is a 100ohm emitter resistor, try a jumper right across the resistor, or put a 100ohm across it [2x parallel 100ohm = 50ohm], reducing the emitter resistor bumps gain.

Side note: I've also considered building a small boost on veroboard and installing it in the case of the muff.  Where in relation to the circuit...[ie if you boost before the diode 'ceiling' will still be seen, if you boost after the boost won't then be attenuated by the clipping diodes or TC.
   I've built an LPB-1 and AMZ Mosfet boost, but both suffered from terrible hum and buzzing.  Any insight into this?   Could be a ground isn't made connection, or something that needs debugging.
I'm running off of the AC adaptor, and both circuits hummed like hell both inside and outside the muff, connected to the muff circuit or not. 
  I hope you mean DC adapter, AC can kill stuff if used as a power supply on components that expect to see 'DC' and correct polarity.
  Gain can't 'fight through' clipping, diodes put a 'hard, impenetrable ceiling' in place, 'clamping' any signal that appears above a certain voltage...boost afterward is allowed 'out', boost before simply makes the clipping more 'forceful'...a harder distortion tone = lower output volume.
 

[blueduck577]

I was reading http://www.student.ru.nl/r.kerkhof/Taas/Mods/Big%20Muff.htm.  Near the top it mentions the resistor mod, involves changing the values of R19 and R12 on the schematic to make the unit more gainy.  The site says to enlarge them, but my (limited) knowledge of pedal modding leads me to believe this is a typo.  Shouldn't I reduce/jump the resistors to give the unit more gain?
  R12 is a 100ohm emitter resistor, try a jumper right across the resistor, or put a 100ohm across it [2x parallel 100ohm = 50ohm], reducing the emitter resistor bumps gain.

According to the schematic I posted, R12 isn't an emitter resistor.  I tried the emitter resistor mod and wasn't completely happy with it, so I'm trying other options.

  I hope you mean DC adapter, AC can kill stuff if used as a power supply on components that expect to see 'DC' and correct polarity.
  Gain can't 'fight through' clipping, diodes put a 'hard, impenetrable ceiling' in place, 'clamping' any signal that appears above a certain voltage...boost afterward is allowed 'out', boost before simply makes the clipping more 'forceful'...a harder distortion tone = lower output volume.

Yeah that's what I meant, I'm using a wall wart with a battery clip.  The thing with the muff is, if I drive it hard with a boost before, it clips more in a fashion that I like.  Boost afterward doesn't really concern me because most of the time I'm playing through my solid-state combo at low volumes.  The muff has so much volume on tap I'm not worried about output volume, just amount of saturation and clipping.

[petemoore]

  Yun likes that.
  I use a compressor or Si Boost before the BMP, and like to think I have common preferences to others, driving the disto to heavier distortion...
  The 'thud' the 'slice' and the 'QUA'.
  QuA is pronounced K Wuh or kwhaa, and seems to be produced with an early transistor is 'railed' to near PS maximum [or high signal swing amplitudes that 'matter' in a PS way], driving subsequent transistors with clipping.
  Thud could be a TS or BMP or DIST+.
  Slice...I like that from a FF with booster in front.
  Points related to using a booster in front of the BMP, IIRC EHX makes LPB's..that'll take a less than hot guitar output and make it much stronger.
  Anyway the way it happens I guess when I like the Qua tone is...booster strengthens the input of BMP's 1rst transistor to the point of making it distort ina way which is different than the subsequent clipping stages, but only during the short durations of attack or heavy low notes [which don't tend toward consonant sounds like the medium registers]. Without a strong signal hitting that first transistor, 'qua-tone' seems to remain less prominent or unobtainable.

[blueduck577]

  Yun likes that.
  I use a compressor or Si Boost before the BMP, and like to think I have common preferences to others, driving the disto to heavier distortion...
  The 'thud' the 'slice' and the 'QUA'.

..

  Points related to using a booster in front of the BMP, IIRC EHX makes LPB's..that'll take a less than hot guitar output and make it much stronger.
  Anyway the way it happens I guess when I like the Qua tone is...booster strengthens the input of BMP's 1rst transistor to the point of making it distort ina way which is different than the subsequent clipping stages, but only during the short durations of attack or heavy low notes [which don't tend toward consonant sounds like the medium registers]. Without a strong signal hitting that first transistor, 'qua-tone' seems to remain less prominent or unobtainable.

yeah, I know exactly what you are talking about an I love it.  i dont want a separate clean boost pedal though because I would probably only use it in conjunction with the muff.  stomping 2 boxes just to get my preferred distortion tone is too much when I have to worry switching on the modulation and delay at the same time, hence the reason im trying to increase the gain of my muff.

[petemoore]

 decisions and the things they influence...
  Perhaps put a booster stage right before the BMP circuit, inside the BMP bypass switch ?