Custom Fuzz-Face Calculator

[Joe Davisson]

Thanks. Trying to test the germaniums is maddening, they change constantly. Getting the right reading for Q1 is the largest problem, since grounded-emitter stages are "stupid" for the very reason of being too Hfe-sensitive. Q2 can be way off and it won't matter, but Q1 needs to be exact. Still trying to figure out what's going on, in the end this may only be a "silicon-only" calculator.

[RockKenny]

Hello guys! Can you add to calculator "Gain Control Value" with 10k. Or share the formulas for self-calculation 10k gain with germanium transistors?

[Rob Strand]

Hello guys! Can you add to calculator "Gain Control Value" with 10k. Or share the formulas for self-calculation 10k gain with germanium transistors?

There's no right answer.  The program kind of makes up sensible R2, R3 values then calculates R1.  The only "right answer" is R1 once the other two are chosen.

For Gain Control = 10k, and R4 = 100k
you can use the program to get three answers:

1)
- Select  Gain Control = 1k, 
- Enter R4 = (100k/10) = 10k
- Calculate
- Multiply all the resistors by 10

2)
- Select  Gain Control = 2k, 
- Enter R4 = (100k/5) = 20k
- Calculate
- Multiply all the resistors by 5

3)
- Select  Gain Control = 5k, 
- Enter R4 = (100k/2) = 50k
- Calculate
- Multiply all the resistors by 2

The program can produce small R1 values. 

If you want to see the formulas just save the web page to your drive and use a text editor to open it.
You will see how certain values are hard coded depending the Gain Resistor Value.

Forgot to mention.  I don't think it allows for leakage.  That might explain Joe's last post.

[RockKenny]

Rob Strand, thx!