Various Fuzz pedal circuits and hiss levels?

Orpheus · May 09, 2008, 10:04:15 PM

Hello, all. I was wondering today why Tone-Bender MKII type fuzz circuits seem to produce a lot more hiss than other fuzz models - like Big Muff, Fuzz Face, MKIII etc, etc? Is this an inherent quality of the Tone-Bender MKII circuit or just my particular experience with all these pedals? Thanks in advance for your insights.

Sir H C · May 10, 2008, 10:06:47 PM

The main causes of noise/hiss:

high gain (the more gain from the input, the more the noise there will be amplified and therefore louder).

high resistances (big resistors are noisier)

Noisy transistors (some of the loved ones are noiser than some of the newer ones)

So high gain germanium circuits with large bias resistors will be the noisiest.

JFX09 · May 10, 2008, 11:59:07 PM

If you want some yummy hiss, I recommend a 2N 2222 followed by a 2N7000: lovely

gigimarga · May 11, 2008, 05:06:24 AM

By far all the Tonebender MK II that i've built had a lot of hiss

Dragonfly · May 11, 2008, 11:24:18 AM

Keep in mind that the TB MKII is a "leakage biased" circuit, which means that Q1 has to have some leakage to stay biased properly.

Leakage = added noise.

Orpheus · May 11, 2008, 04:03:31 PM

Thanks for the great insights, all. So, it looks like the MKII has everything it takes to be very hissy then: leaky Q1, 3 transistors, high-gain and a bright frequecy response...

Sir H C · May 11, 2008, 06:01:16 PM

Right, but the other side of the equation is, the sound!

Orpheus · May 11, 2008, 07:34:51 PM

Quote from: Sir H C on May 11, 2008, 06:01:16 PM
Right, but the other side of the equation is, the sound!

I hear you, Sir. Various fuzz pedal types all have their wonderful tones, yet there is something about that MKII tone for me too - so bright and spitty, yet rich and searing with that incredibly organic fade out character.

Sir H C · May 11, 2008, 09:05:29 PM

One great thing about the old fuzzes is that they didn't try to engineer all the noises and weirdness out of them, so you get some really weird and unique sounds. Love those 60s freaks.

Orpheus · May 11, 2008, 09:25:52 PM

Quote from: Sir H C on May 11, 2008, 09:05:29 PM
One great thing about the old fuzzes is that they didn't try to engineer all the noises and weirdness out of them, so you get some really weird and unique sounds. Love those 60s freaks.

Right - I think that's what makes them sound so organic. That unpredicatability of tone.

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Various Fuzz pedal circuits and hiss levels?