MISS PIGGY SCHEMATIC NEEDED

[brian wenz]

Hello Hello--
   I need a copy of Bretts' "Miss Piggy" schematic..........tried all the usual places.   [Can't seem to get it off of Brett's site, either!]
Thanks-
Brian.

[Chris R]

cant find the schem either.. but there is a layout on brett's site

http://members.optusnet.com.au/~jethro.dog/mypic119.jpg

it should be easy to draw out a schem from that.

C

[petemoore]

..And can easily be adapted to perf.
 That diagram is well drawn, use a Standard FF schematic for reference if needed, it should be very same if you eliminate Q's 1 and 3 [with the N/C collectors], and the associated emitterz resisterz. Also Q2's collector trim, but these should bea given to DIY FF's...at least a socket for R swaps there...plug your trimpot in the socket etc.
 I see reasons that a more advanced FF builder might want that as a chosen fixed value. Otherwise [expecially] the FF experimenter should Have a Trim on Q2C for Biases.

[brian wenz]

Hello Hello--
 Thanks!
Brian.

[brett]

Hi.  This is the schematic;


Try varying the 1k and 2k emitter-coupling resistors for different sounds.  Also, I have tried power transistors like the BD139 for Q1 and Q2, and quite liked them (lower gain, more responsive to playing style).

cheers

[brett]

Oh yeah, I nearly forgot this good trick.  For a high-gain fuzz make the 33k resistor 100k and drop the 100k feedback resistor to 47k.  That gives something more like a classic Si fuzzface, but still with some magic of its own.

cheers

[brett]

Here's a schematic of a high-gain Miss Piggy I call the Quatre (french for "four").


Cutting the input cap to 0.047uF make it a treble-booster, too.
cheers

[will]

Hi Brett,

Your high gain Miss Piggy Quatre is missing its emitter-coupling resistors. Which turn the transistors into low gain. This seems odd for your high gain circuit.  :?

How does it compare with your regular miss piggy? Is it like a fuzz face with a booster in front?

Regards,
Will

[brett]

Hi.
I really only built this Quatre as a kind of Rocket (Aron's design) but with piggybacked transistors.  It was built when I first fooled with piggybacking, so I've had it sitting around for a long while, not being used.  In fact, I had forgotten that it was different enough to the Miss Piggy to be interesting.  

But when I hooked it up the other day I really liked it.  More "punch" and transparency than a Miss Piggy.   :oops:   Less "classic" sound, maybe, but still quite a good sound (kinda like an RM Axis fuzz).

I suspect that the higher gain comes from the 5k pot +1 k fixed resistor used on the emitters of Q3 and Q4.  To balance the higher emitter  resistance, there's also more collector resistance (about 50k :shock: ) on Q3 than a Miss Piggy.  In AC terms, I believe that the gain is dependant on 2 things:- the size of the collector resistor and how far the fuzz pot is turned (because the 22uF cap is AC ground).  Because the collector resistor (the 100k trimpot set about 1/2 way) is 6 to 10 times the usual fuzzface value, you get a lot more "kick" from this setup.  (I think the JH-1 fuzzface did a similar thing, less pronounced by using a 2k pot and an 18k collector resistor).  

Also, I found an extra 22uF cap on the underside of the board, so it's really 44uF (47uF close enough) on the emitters, which also lift the gain relative to the 22uF cap in the Miss Piggy.

Next weekend I plan to try out some different configurations of Miss Piggy and the Quatre.  One option is to have 1 tame and 1 wild fuzz.  e.g. Tame the Miss Piggy even more by reducing or eliminating the emitter-bridging resistors, and up the gain on the Quatre by swapping from BD139s to PN100s or 2N3904.

cheers

[brian wenz]

Hello Brett--
  Sounds great....can you post the results [along with any schematics] of your experiments??
Thanks-
Brian.