Tortuga Effects Yeti = Triangle Big Muff

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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mauman
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Post by mauman »

I had one of these for a while, serial # 011 from 2009, and decided to trace it. I got far enough to realize it was looking a lot like a Big Muff, so I spot-checked the rest, and indeed it is. Starting from a stock Triangle BMP schematic, you can make these changes to get a Yeti:
  • Q1 - Q4 = BC239C
  • Add the AMZ Presence (mids) mod, except it's a 4-position switch instead of a pot, with the 4th position bypassing the Tone pot
  • Sustain pot is A100k instead of B100k
  • DC filter cap is 220uF instead of 100uF
Here are some pics for the record. I didn't trace the Midrange mod switch in detail, the traces in the pics were obscured by the rotary switch and I no longer had the pedal in hand. If the knob labels are obscure, here are the builder's notes:

"Howl = Volume
Scream = Tone (see Note below...)
Growl = Fuzz
Anger = Four position rotary tone switch
Position 1 = Classic scooped mids
Position 2 = Flat mids
Position 3 = Mid hump
Position 4 = Tone bypass (slight volume boost)

"Howl" and "Growl" are pretty self explanatory after you start tweaking them. By turning the "Scream" tone control clockwise you make the treble more present and by turning it counterclockwise you bring out more bass. The "Anger" four way rotary switch gives you some distinctly different voicings. The fourth position will be louder than the rest, since it bypasses the tone circuit and your “Scream” knob. "


Yeti (8).jpg
Yeti (7).jpg
Yeti (1).jpg
Yeti (9).jpg
Yeti (6).jpg
Yeti (2).jpg
Yeti (3).jpg
Yeti (5).jpg

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