M. Scibor-Rylski, Fuzz Box, in: Practical Electronics, July 1966 🇬🇧

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modman
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Post by modman »

Hi-res PDF with cover:
Practical-Electronics-1966-07 fuzz box.pdf
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BMS1971
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Post by BMS1971 »

Interesting no gain control and 4 transistors. That must scream like a banshee!

Ben

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Post by BMS1971 »

Made it with MP0A. well... savage gated fuzz... The only change I made was R4 down to 120K, more usable range on volume. 56K was much better but a BIG buzz came with it. Tried to remove it wit a capacitor between B and C 100Pf, but no luck so far. If anyone has an idea I'm open to suggestions

Ben

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Post by SN76477 »

Yes, it screams like the wildest Banshee and will get through any mix like a razor blade! Sounds awesome paired with a Wilson Haze Uni-vibe.
I built one with MP41A transistors. Looking at the circuit topology, I ended up replacing R1 with a schottky diode in the first stage... Bazz Fuss style :wink: ...
Low leakage Ge PNP gave the best results...
I tweaked ALL the components values in the process to get the sound I was looking for... Speciality sharp-velcro-buzz fuzz to fry them all!
Here what I ended up with :

R1 : Diode instead 1N5818 (240mV)
R2: 100K
R3: 3M3
R4: 330k
R5: 10k
R6: 100R
Added a 1M pulldown resistor to prevent switch pop
C1 : 0.22uF
C2: 4.7uF
C3 : 0.022uF (Razor sharp! :twisted: ) May use larger value to prevent eardrum bleeding.
Added a 47 uF filtering capacitor at power supply
D1 : Ge (860 mV)
Added a reverse polarity protection diode at power supply
Q1-4 : MP41A (Ge PNP) Q1 Hfe 70 - 0.03 leak. Q2-4 Hfe 60 - 0.06 leak.
Used a 2K linear pot with a 2k2 resistor between lug 1 & 3 as a substitute for the 1k volume pot.

Use at your own risk!

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Post by SN76477 »

By the way, Doctor Mark Scibor-Rylski is still a very active/innovative engineer!

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