I love the whole thread on piggybacking transistors, although I think much of it is beyond me.  So, what's the final verdict of the best sounding schematic and transistors to use (closest to a FF)?  And is there a Tonebender one?  Thanks.
-Joe Hart

Hi.  You might have seen this layout on another thread, but I'll post it here anyway;


It's my latest "best bet" for a good Miss Piggy.  If you get radio frequency interference, try a small (100pF) cap from the base of Q1 to ground.  Otherwise, this layout builds an awesome fuzz.  For some reason the PN100 transistors seem suited to this circuit.  I don't know how available PN100s are in other parts of the world - if you can't get them I'd suggest 2N5088s or 2N5089s.  With the 1k and 2k resistors I feel that you get a pseudo-Germanium sound (but with lots more clarity and sustain!).  Higher value resistors turn it into more of an Si fuzzface sound.

Hi Brett...

I seem to remember you mentioning that either the pin designation or the case orientation for the transistors were wrong at one point. According to the Fairchild PDF, the pinout for the PN100 should be EBC so something doesn't jive. I wasn't able to find the actual schematic for the Miss Piggy, so I couldn't verify. Using your layout, I'm guessing the pins are supposed to be CBE (top to bottom) and that the case orientation is wrong.

I'm asking because I'm doing a PCB layout. I can't wait to try this out!

Thanks in advance!

Hi.  Absolutely right that Fairchild PN100s come in E-B-C configuration.  I must have some other brand.  They are definately PN100s and definately C-B-E.  Don't you just hate that! :evil:

The layout above is for the C-B-E ones, so turn around your Fairchild  transistors.n(face them to the right)

Thanks for picking this up.

Quote from: Dean HazelwanterHi Brett...

I wasn't able to find the actual schematic for the Miss Piggy, so I couldn't verify.

Does anyone know where the schematic is??  I know I can read a schematic, but I'm not so confident about working backwards from the parts layout picture.  Thanks.
-Joe Hart

I just made up a schematic for the Miss Piggy. It's here http://members.optusnet.com.au/~jethro.dog/mypic110.jpg

I'm fairly sure I got everything.  Hope it helps.

Quote from: brettI just made up a schematic for the Miss Piggy. It's here http://members.optusnet.com.au/~jethro.dog/mypic110.jpg

I'm fairly sure I got everything.  Hope it helps.

Thank you.  I can't wait to build it!!!
-Joe Hart

brett, did you ever come to a final decision on where to add a capacitor to emulate germanium a little more? Could you update the schem? Or list out specific mods to try?

My favourite mod is to add some some base-collector junction capacitance, which I think is a key characteristic of old Ge transistors (RG has also said something along those lines).  Funny thing is that adding it in the Q1 position on a standard fuzzface doesn't seem to smooth out the sound much.  I've even noticed a couple of jagged edges appear on the trace if you put too much capacitance on Q1 and have none on Q2 (of a Fuzzface).  So I think for an Si fuzzface, either put about 100pF across the base-emitter of Q2 or, for a more dramatic effect, put 220pF on Q2 and 100pF on Q1.  (On a Miss Piggy that's 100pF on Q1 and 220pF on Q3).

This seems to give a slightly different effect to bypassing the collector resistors with a small cap.  Can't say it's necessarily better....but it's more a kind of replica of the faults of old Ge transistors.

cheers