MountaintopPedals
Member
Is there a reason pedal pcb boards for pedals with GE transistors don't have trimpots for biasing the transistors? What resistors would be replaced with trimmers to bias the transistors on the Mister Fuzz?
Mister Fuzz
- Thread starter MountaintopPedals
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Feral Feline
Well-known member
Never noticed PPCB Ge-based boards not having trimmers.
I've read somewhere that trimmers (ie variable resistor) can be noisier than a fixed resistor. Whether it's true and to what degree (noisier on an oscilloscope but not to human ear?), I don't know. Trimpots have moving parts that may likely fail before a fixed resistor would. Fixed resistors can't accidentally be bumped from their optimum setting.
Breadboarding can be fun and allow you dial in a circuit before committing components to solder; You could play with R7 and R9 on the Mister Fuzz.
I've read somewhere that trimmers (ie variable resistor) can be noisier than a fixed resistor. Whether it's true and to what degree (noisier on an oscilloscope but not to human ear?), I don't know. Trimpots have moving parts that may likely fail before a fixed resistor would. Fixed resistors can't accidentally be bumped from their optimum setting.
Breadboarding can be fun and allow you dial in a circuit before committing components to solder; You could play with R7 and R9 on the Mister Fuzz.
Feral Feline
Well-known member
Ahh... still so much for me to learn...
MountaintopPedals
Member
The Aion Tone Bender MK II I built sounds amazing and it has trimmers to Bias Q2 and Q3. The trimmer isn't going to fail as its set it and forget it. If you're worried about someone messing with it put an ink line across the trimmer at the bias point.
Aion Tone Bender
Pedal PCB Bender
Pedal PCB Maestro.
I have 6 2N270 Transistors.
Coda
Well-known member
The MKII is a different beast than the MK I Tonebender, which operates the same as the FZ-1. The MK II does not rely on the leakage of Q1, like the MKI/FZ-1...
Robert
Reverse Engineer
There was no malicious intent to harm the trim pot industry... 
At the time most of those were drawn up it was fairly common to order transistor sets from Smallbear, which in a lot of cases included the required value bias resistors.
You can easily replace any resistor with a trimpot with the Trimmit.
At the time most of those were drawn up it was fairly common to order transistor sets from Smallbear, which in a lot of cases included the required value bias resistors.
You can easily replace any resistor with a trimpot with the Trimmit.
fig
Village Idiot
Right, It's the 9mm pots we're gunning for.There was no malicious intent to harm the trim pot industry...
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