UFO - 'Unidentified Overdrive' - anyone know what this is?

[tubesimmer]

Have this schematic. All I know it's a clone. Of something.
But what?

It features 2 op amps, shorted 7002 MOSFETS and 3 Schottky diodes in the FB loop, and a simple tone control.

Anyone recognize it, or the closest variant using this kind of MOSFETS / Schottky clipping?



Maybe I should have posted this to the Members Only forum - if so apologies, I can take it down & repost!

[Kipper4]

Welcome
Looks like a zen drive variant.

[tubesimmer]

Looks like a zen drive variant.

Indeed it is.
Thanks a ton.

[duck_arse]

interesting. the BB112 is not a schottky, it is a varicap diode. as the applied voltage changes, so does its capacitance - they are used to tune oscillators. they are such a strange choice for this application, the datasheet doesn't even mention a forward voltage figure.

[tubesimmer]

interesting. the BB112 is not a schottky, it is a varicap diode.

Likely a mistake in the SPICE diode choice. I also can't find the forward curve for a varicap offhand either...