I had some extra time so I built a clone of the Red Fuzz at GGG. After changing the jfet for a ge transistor, I decided to use Joe Davisson's diode compression opamp instead of the LF351, but using ge diodes and transistors... just for fun.
I picked a couple of 2N3906 hfe: 150 and a 2N3904 hfe: 265 first. Then instead of the si diode I used a 1N60 ge diode and two series 4K7 instead of the 6K8 to get 4.6V at the ouptut. I wonder if I had to modify the 100k because of the lower voltage drop but it seems to work fine. With two series 1N60 the 6K8 is ok.
Then I changed the transistors. A ge npn 2SD352 hfe: 100 leak: 300uA and two almost identical ge pnp 2SB175 hfe:155 leak: 110uA and two series 1N60. I had two change the 6K8 for a 3K3.
Ge diodes gives more fuzz, and even the lower gain than specified transistors, 2N5087 & 2N5089, the amount of gain is good. There is a subtle difference when using one or two ge diodes, but I can not say which I like most.
The all ge version has lower gain as expected, as the npn ge has not much gain. I wish I had a high gain low leakage npn ge.
Maybe I should have to modify the opamp to be npn input, pnp output to use my ge high gain pnp.
Because of the lower gain I can not tell If using three germs is justified.
Despite the ge flavour, the opamp behaves much like a std ic, but the diode in its guts smooth the sound even without external clipping leds. Nice.
I like the opamp as is, but ge diodes gives that ge fuzz tone I am always looking for. But this is my personal taste.
Come and taste the ba... eemmhh ge diodes.
mac
