4016 switch fuzzer schematic

[gez]

I managed to find a few minutes to finish the 4016 fuzz idea I posted the other day.  Don’t expect sonic nirvana, but it’s a fun and simple build.  Lots of crunch and a metal-like tone, which isn’t bad for one stage!

http://hometown.aol.co.uk/Gezpaton/Scuzz+Box.gif

If you look at the schematic for the 4016 there’s an inverter between the input and p-channel, so although there’s just under .5mA of current flowing through the switch’s channel, the total current consumption is just under 2mA (I measured 1.86) due to the class A current of the inverter.

Another quirk of this circuit is that the p-channel is acting as a follower but, because of the inverter, gain is well above unity.  This means that if you wire up what would be a source resistor in a common source amp, from pin 9 to ground, there’s no huge reduction in gain as it’s acting as a drain resistor for the p-channel.

I was too lazy to wheel out the scope, but I wired in different values of ‘source’ resistor and it made precious little difference to the circuit.  There was some reduction in fuzz but I’d suggest that this was due to the reduced Vds across the channel.  Connecting the 500k pot to the resistor wired from pin 9 to ground confirmed that there was indeed a huge amount of gain to be had from this output and not unity as one might first have thought.  

This means that if divider bias were used and the amp were wired  as a phase-splitter, gain would be well above unity.  Might have some interesting effects in a vibrato/phaser circuit?  Then again, how stable it would be with a divider is anyone’s guess! (trimpot would probably be the way to go?).

Have fun!