Skreddy Pink Flesh questions

[TKS]

First off I will start by saying that I own a Pink Flesh and it is my favorite (only) fuzz.  I was going to get a second one as a backup but since they are now discontinued I thought I might try to make one for myself I even have some of the same transistors that are in the Skreddy's.  My question is, is the PF a Tri. BMP with a different tone stack (tweaked values) or did Marc add components to a Tri. BMP?  I was thinking about tracing it out myself but if anything happened to it I would freak.  Anyone know?

[DougH]

Why don't use ask Marc? He hangs out here sometimes.

[Skreddy]

It's just a BMP with tweaked values and maybe an extra cap or resistor around the tone stack.

The reason I discontinued it was my last order of 2N5133 transistors did not contain any that were high-enough gain.  Turns out I have a few bags of those that I had summarily rejected earlier but can still be used if I test them carefully for noise and pay attention to which parts of the circuit can use which gains.  I don't want to put the Pink Flesh back into open production, but I will still try to fill orders for them for as long as I can.

There are many, many ways to get great tones out of the BMP.  For me, I generally start with the transistors and work my way out from there.  I find that I don't have to travel too far from the values of the triangle knob version to get most of what I want them to do.  Substitute a 10uf electrolytic for the input cap, tighten up the bass and add a bit more lowpass filtering at the tone stack, and you've basically got something that is capable of decent Gilmour-ish tones (assuming all the individual components sound good, etc.).

There's nothing special going on.  All pots are 100k L.  The clipping diodes are regular small-signal silicons.  The big diode is just a DC blocker for the power supply--you can use germanium or a schottky.

[manson]

"Substitute a 10uf electrolytic for the input cap" .. that's quite far from the original 0.1uf .. Doesn't that make it extremely bass heavy? Why did you make this change if I may ask?

[DougH]

I generally start with the transistors and work my way out from there.

Are you saying that transistor types make that much difference in a BMP? With 3 gain stages and all that diode clipping?

[Skreddy]

"Substitute a 10uf electrolytic for the input cap" .. that's quite far from the original 0.1uf .. Doesn't that make it extremely bass heavy?

You'd think so, wouldn't you?  But no; it's not as bassy as you might think.  An electrolytic needs to be a pretty large value to pass a decent amount of audio bandwidth compared to film caps.  The 10uf electro adds more saturation and has another pleasant side-effect of allowing you to turn down the sustain without the tone getting all gritty. 

Why did you make this change if I may ask?

It wasn't even my idea; it's the "ram's head" version's input capacitor.

I generally start with the transistors and work my way out from there.

Are you saying that transistor types make that much difference in a BMP? With 3 gain stages and all that diode clipping?

Yes.  For example: start with four circa 1969 Fairchild 2N5133's and build a stock triangle-knob BMP; and you'll get a smooth, harmonic, mellow, dynamic, amp-like sound.  Do the same with four modern 2N5088's, and you'll get a glassy, fuzzy, aggressive, compressed, transistory sound. 

The clipping diodes don't just clip the signal; they interact with the transistors in a negative feedback loop.  The transistors' basic personality will still fundamentally shape the response of the circuit.  There are many more factors involved than hfe and cin.  The more you press a transistor beyond simple linear mode and the more you multiply this behavior (with multiple stages), the more profoundly you'll bring out its subtle quirks.

[soggybag]

Sounds like some good suggestions I'll have to try out 10uf input cap.

[SonicVI]

Here's a pic for fun of my "Ram's Head" with the 10uF electros. Trannys are original 2n5133's.  I made a triangle clone (even used the original pcb pattern) using newer 2N5133's, carbon comps, and all ceramic caps and it's true the Ram's Head is not at all bassier.

[ultar]

has anyone here used the 2n5133's stocked by small bear? just wondering how they sound in the muff circuit.

[SonicVI]

I used the Small bear 2n5133's in my triangle clone and it sounds pretty good to me, very very similar to the above ram's head.  I ordered 20 of them and most of them were pretty low gain. I used the four highest gain ones I got which were around 400, most were under 100.

[SonicVI]

Although, when I measured the 5133's in my ram's head they were also pretty low gain.

[ultar]

thanks for the info. i'll be ordering some soon to try out in different circuits. might sound good for a silicon fuzz face is the gains are around 100.