NG-4 Fuzz

From the vendor

NG-4 Fuzz

Aug 28, 2024 2 min read

Bootstrapping is great, I said as much myself. Sometimes that love gets a bit too far, sometimes you build a whole career on it. Either way, we're back to fuzz today, the simplest and most ubiquitous guitar effect on account of being able to achieve it whether you want it or not. Back to having fun with derivative circuits and paring them down, because the chance was too juicy to pass on this time, and because it's been too long.

The circuit

The circuit, in its current form, is quite compact and one could say muff-inspired, with two transistor clippers wrapped into input and output stage, and with a similar passive "tilt" EQ.

Everything seems a bit more extreme than in that venerable circuit, with plenty of input gain, grounded emitters, one of which directly (which predictably needs a bias control), and attenuation instead of make-up gain at the end because of the larger swings. This probably results in high noise floor, but I'm not the one making the choices today. The approach is the same as always with derivatives: trying to make the simplest circuit that sounds and behaves exactly the same, without coming down to compromises. In this case, this mostly involved removing an input buffer, which was adding noise in front of an op amp amplifier that didn't need the buffering; replacing another bootstrapped buffer with a spare op-amp; rounding component values to more common ones without compromising the result; redoing the bias voltage without a zener diode, whose precision seemed unnecessary for an adjustable control on a predictable enough supply voltage; simulating the actual input impedances and matching them without bootstrapping. One could probably remove a couple more components without side effects, but it doesn't seem worthy.

Demo

Thanks to crxst, who tested this circuit for me and recorded some noises (all the merits to him, all the demerits to the circuit!):