muff transistors hfe's

[makaze808]

hi, I want to build a muff (yawwwn) with some vintage trannies I've found.

I have hfe's of 500 500 250 200.

My question is would the higher gain ones be better placed in the middle two clipping sections or at the amplifier and recovery stage.

would normally breadboard but bread board has died.

Thanks.

[Mark Hammer]

The "gain" of transistors is often misunderstood.  I don't quite understand it myself.  What I do know, however, is that it is dictated by what is around the transistor, and not by the transistor in spite of everything around it.  Some of the most intense legendary fuzzes are made with transistors having hfe noticeably lower than what you have there.  As for the BMP, its essential character is dictated by the fact that it double-clips (clips, re-amplifies, and clips again).

So, ultimately, I think you are wasting time and effort debating your choices when you should just go and make the damn thing, and then ask questions about what you mght change to get a little more of this or that.  I mean, what would you rather be doing: waiting for an answer here, or rocking out? 

[Scruffie]

Or... Sockets! Problem solved.

If I was taking a stab in the dark, which I am, i'd put the 2 higher gains in the middle... dunno why, seems right.

[EATyourGuitar]

Q1 is basically a clean boost. Some people just remove it. It doesnt have clippers directly after it so i dont think its all that important. Especially if your putting a loud pedal before it. Im looking for high gain npn's at the moment to go in my mojo triangle on the pigeon fx pcb. What kind of transistors are you using?

[runmikeyrun]

socket and experiment.  In my opinion you should ALWAYS install sockets any time you build any fuzz with transistors or opamps.  I spent quite a while experimenting with mine after i built it, but didn't find much difference in transistor placement.  then again, all my trannies were pretty close in HFE.

[stringsthings]

hi, I want to build a muff (yawwwn) with some vintage trannies I've found.

I have hfe's of 500 500 250 200.

My question is would the higher gain ones be better placed in the middle two clipping sections or at the amplifier and recovery stage.

Big Muff Pi Time !   .... your question is a good one ! ... it sounds as if you have some nice transistors ... the BMP is not real picky on selection of transistors ... as long as the hfe of each of the 4 transistors is at a reasonable level ... ( 200+ will do nicely ) ... as suggested, you may want to use sockets and do some experimentation ... if your transistors are valuable to you, you can try some less vintage ones first ... the 2N3904 ( which is cheap as chips ) works fine in many BMP builds ...

while you're at it, you can also play around with resistor/capacitor selection in the tone stack ... this part of the BMP can make a big difference in the overall sound of the circuit ...

and remember, there's no such thing as too much Big Muff Pi !  

[stringsthings]

 double post ... oops 

[mac]

The only difference I see is base impedance given by zb=hfe*emiter_resistor, and how this difference might effect the lows that are cut by the 0.1uf in series with the 10k... 
It is quite possible that clipping diodes disguise this effect... 
Just a thought.

mac