Black Russian Big Muff resistor question

[SidSeizure]

Since I bought a NYC Big Muff I haven't been using my black Russian Big Muff, so I decided to mod it. I was comparing schems of earlier models and I noticed that most Big Muffs have a 1k resistor to ground off the sustain pot. The black Russian has a 10k resistor in this position.

So I have two questions: 1. How does the resistor size on the sustain pot affect the output? 2. Which of the three 10k resistors on the board is the one connected to the sustain pot?

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/blackrussianbmp.JPG.html

After a lot of time spent following traces and looking at a schematic, I thought I had the right resistor. I carefully removed the one marked 1 on my photo above and put in a 1k resistor. Wrong. All that did was reduce the volume, so I carefully replaced it with another 10k. So now I have a 50% chance of guessing the right one to replace since I can't seem to figure it out on my own. Can someone help me?

[SidSeizure]

Since no one bothered to point out that I'm an idiot, I'll do it myself. 

After studying the schematic and the board for who knows how long, I totally overlooked the fact that the schematic has four 10k resistors on it, not three. Also, I found a 1k resistor on my board that's not even in the schematic. This resistor connects to lug one of the sustain pot, just like the green Russian model and most other Big Muffs. Therefore, the mod I wanted to do on this pedal was done in the factory. Grrrr!

They really do build Big Muffs kind of randomly, don't they?

[bumblebee]

If you decrease the 10k resistor to 1k it will result in more sustain, its limiting the sustain too much IMO at 10k. I modded my old black russian to a green russian X NYC muff and its seriously one of the best sounding muffs I've ever heard.
The 10k resistor is this one, the one in green. (Number 3) In black muffs its 10k, I've never seen it anything but 10k.

[SidSeizure]

Thanks, Bumblebee. I wish I had your diagram yesterday, it would've saved me a lot time.

It's odd that my black Russian BMP has a 1k where most others have a 10k. Mine also has a 20k in the tone stack where your diagram and the schematics I've seen show a 22k. It's like mine was nearly modded to green BMP specs before I got it. Weird. It doesn't look modded, but I got it used on Ebay, so anything's possible.

I wish I'd have thought to make a photo like yours with the traces showing through. I own a light box and could have easily done it. Ah, live and learn.

[bumblebee]

Someone obviously modded it then.
I found that PCB pic on the net ages ago, its my standard go to diagram for all thing russian big muff. Makes it a hell of a lot easier to find components ya need to change, I've never bothered to learn resistor color codes, I know a few but not many.

I put together some mods for the black russian, sounds awesome, its across between the green russian and the NYC.
You should try it, you wont be disappointed,its the best sounding big muff around IMO and isn't boomy with guitar chords, it isn't muddy with 'em either. (use box caps not electro's for the 1uF's)



If you do do my mods let me know how it goes and if you like it or not.

[SidSeizure]

That looks interesting, Bumblebee. I may just have to try that mod since I'm not using my Russian Muff anyway.  Thanks for the info!

[DiscoVlad]

It's odd that my black Russian BMP has a 1k where most others have a 10k. Mine also has a 20k in the tone stack where your diagram and the schematics I've seen show a 22k. It's like mine was nearly modded to green BMP specs before I got it. Weird. It doesn't look modded, but I got it used on Ebay, so anything's possible.

Mine's the same, and was bought brand new. There's a sticker inside with "2006 34" on it, which I assume means it was made in week 34 of 2006.

Maybe newer ones have gone back to the Green Russian circuit?

[phillipislbj]

Thanks, Bumblebee. I wish I had your diagram yesterday, it would've saved me a lot time.

It's odd that my black Russian BMP has a 1k where most others have a 10k. Mine also has a 20k in the tone stack where your diagram and the schematics I've seen show a 22k. It's like mine was nearly modded to green BMP specs before I got it. Weird. It doesn't look modded, but I got it used on Ebay, so anything's possible.

I wish I'd have thought to make a photo like yours with the traces showing through. I own a light box and could have easily done it. Ah, live and learn.

My black muff also has a 1K resistor in it. They must have had a run that used the 1K instead of 10K.

[Marty]

Mine also has a 1K.  What difference would changing the other two resistors  make?

[bumblebee]

I @#$%ed up in my first post to you dude (probably half asleep). What I meant to say is thus> at 1k the MINIMUM sustain is less than if you have a 10k there. It doesn't effect the MAXIMUM sustain, only the minimum...when you have the sustain knob down low. At 1k more input signal is getting shunted to ground hence less passes thru the rest of the circuit. at 10k the minimum sustain is more on the lowest settings than if you use 1k.
I hope I didn't cause too much confusion.LOL
The other 2 resistors dont change much at all really. You'd be hard pressed to tell the difference in a blind test from a black sovtek to a green one.

[noelgrassy]

Mine has the "Green" values as well and they're obviously the factory's components. This one
was free as my girlfriend found it left on the ground at a homeless shelter and brought to me.
The russian puppies aren't so bad. In the mid 90s a friend gave me a Civil War pedal because he
thought it sounded like ass. I got it minus that top coverlet but it's always made my lapsteel
sound killer. I defy any Uhmercun to ID those brown parts and xistors! What was the deal with
that spaghetti system with the stringy umbilicals running parallel to the wire leads? Damn thing
roars though....

Noel Grassy.