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BiG Muff Which one???????

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6/9/1997 2:58 PM

BiG Muff Which one???????

To my knowledge their are two different versions of
The Muff the Fat sounding one which is the one that the schmatic is floating around the net.
and there is a newer version not made by sovtek but the one that came out after the first muff
I read that the circuit was changed i opened up the case of it and i noticed that the Transistor stages are reversed!
I've compaired the board with the Original schmatic and and most of the parts were the same just it looked like the
Componates on the Stages of the Transistors are on the emitter instead of the Orignals collector.
Can someone shed some light on this???
Thanks alot!
Jeff

6/10/1997 6:56 AM

I drew the one that is floating around the net, originally for Leper's schematic archive. EH did make two or three versions of the BMP with transistors, but the circuits are pretty much the same, just slightly different names and cases.

This one could be different because of a change of device pinout, of a different type used for one production run, or it could be a PNP version which would look like the devices were reversed.

More degenerate solutions are that it has been "improved" by someone playing with the circuit...

If the transistors were really reversed, they would not have enough gain to make the creamy fuzz that the Big Muff was noted for, as the reverse beta on silicon devices is MUCH lower than the forward beta.

There are two versions of the BMP (other than this one, which may represent a third). The second version I know of has an opamp with a stack of three pairs of clipping diodes around it. This is clearly not what you have.

Did you try the tracing technique I have on my web page? Tracing the copper pattern onto clear mylar with a "Sharpie" lacquer pen? This really clears up the tracing problem, no flipping the board over to follow copper paths.

How does it sound???

6/10/1997 4:41 PM

To RG!!! Regarding the mUff

Hi there!
Ok the Muff i have i believe is the Version 2
i was talking to a friend and he said that it was indeed a version 2 by just looking at the case ummmm,......you asked how it sounds well compared to my Muff that i built off your Schmatic that you say is the original one it has a hellova lot more gain than the one on the schmatic it also has alot more highs and less grit turning the knob to the deeper sie makes it not so deep as the muff i bulit not nearly as deep! I love the sound of this one for solos and for new age alternitive thats why i want to figure out what the difference is in the schmatic i have noticed that it uses BC239 transistors and the diodes are put on the emitter also......I'm in the process of transcribing this circuit when i get it done i will put it on the web! ok,.....
Can you shed some light on this some more!
THanks alot!
Jeff

6/10/1997 6:27 PM

>>compared to my Muff that i built off your Schmatic that you say is the original one it has a hellova lot more gain than the one on the schmatic<<
Like all things that are sensitive to the device characteristics, every copy will carry it's own personality. There probably isn't any "one on the
schematic" that you could point to.

What transistors did you use in the clone you built from the schematic? Lower gain devices will give a -- well, lower gain. EH probably used a house numbered 2N5088, as they did in a lot of their stuff. This has typical gains of 300.

The higher gain devices like 2N5089 (500 to 1200) and perhaps MPSA18 (1000 minimum) will give MONDO gain in there. The clipping diode characteristics will also affect the perceived gain, with germaniums increasing it even more.

The tone differences could also be changed by twiddling the cap values in the tone filter section. Try doubling and halving the values there to see what suits your taste better.

I'll be very interested in what you find in the schematics. If you run into problems, I'd volunteer my time to trace it out and compare it to the "reference" circuit.

6/10/1997 6:58 PM
Paradiddle	Yeah Ok,.....I'm still tracing the circuit i have tryed many different transistors but they all sound the same in my circuit! Jeff

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