Big Muff pi Mod for more drive?

[Yun]

time for more "yun mods" 

-Jumper Q1, Q2, and Q3's emmiters straight to ground.  The Transistor after the tone control:  the emmiter's resistor to ground should be around 330-390 ohms. 

-Put 3 diodes in series (on each side) on all clipping circuits.  i prefer silicon (1N914 to be exact)

-IF you do the diode mod:  Looking at the BMP tone circuit:  .1uf needs to be .047uf, .004uf needs to be either .0033uf , or .0022uf .  As the more diodes you put in series the more bassy or "muddy" the overall tone will get.  The big-muff tone circuit is really muddy natured, in my opinion....

-Try putting a Muff fuzz right before the sustain control.  Looking at GGG's layout- it's C9 i believe.  but don't quote me on that, man. 

-try replacing the 8.2K, or 10K resistors (depending on what version you're building) with either 12K-18K . 

These are some mods to start out with, man.  That should do youse well enuff for now, dude.....

Here's the schematic to a "creammy dreamer-ish" big-muff: 

[g.e.o]

Sorry.

How much gain are we talking about?

In the simulator, the existing stage shows a gain of about 35db (56x) open loop, and about 28db (25x) closed loop. Messing with the circuit components as I described can get you another 2x to 4x. That may or may not be enough for you.

No need to apologize.  there's no problem at all. i just dont think its proper to have arguements that dont aply to the question.

i think the increase u desribe will be fine. i just need a bit more gain.

But listen to this that i think will be interesting for all of ya. i spoke today to Mr. P.Cornish and asked him about this thing. his 1st reaction was "what? more gain out of this thing?". then when i explained why i need the extra gain (i need it only when the tone is set to 0) he said that "the muffs have that problem. the tone control part is not designed well" and suggested to just take off the tone control and "see what happens. trust me". he also suggested to put a collector from the last cap of the tone control stage to the volume control. i think this is very interesting coz there will be no adjustment for the tone and maybe i will get a fuller sound with all the possible gain i need out of it. of course he knows much more than we do so i'll give this a try and.....see what happens as he said.

anyway, thanx for all the replies and would appreciate more ideas coz these posts may help lots of people in the future including me. by the way, Pete Cornish is extremely COOL! would never expect him to be that friendly and no snob at all! i even asked him stuff about Gilmour's equipment and what did he do and answered all my questions. GREAT man he is!

George!

[g.e.o]

forgot to thank yun as well

so thanx for the reply man! i'll take a look at this. at the end i think all the suggestions may give us all a very good solution in such a problem. take care!

[brett]

Hi
Thanks g.e.o for asking such a great question, and to RG for explaining the ss feedback operating in BMPs.

I finally found out why my BMP has so much gain.  I kept thinking that changing the 8k2s to 10k would have almost no effect on imput impedance, and if anything, it would lower the gain.  I totally forgot replacing the 39k series input resistor with a 10k resistor too.     So my gain was up by about 4 times!

Serendipitously, that also indicates an option for g.e.o.  Drop the input resistor to 22k for a few dB extra gain or, like me, use 10k and get a wild, fire-breathing beast.

Cool thread but for the brief rudeness.

cheers

[g.e.o]

Its ok Brett. Thank u for ur replies. as i said in a previous post all these things said here will help many people whatever their problem is with the sound of a big muff. and here u r. u found out what ur problem was. am very glad we both got our answers from my thread . More suggestions to this still wanted though. as i said we can help more people.

Thank u all.

George