Thoughts on Friedman Fuzz Fiend Tube Fuzz?

[mzy12]

I've been intrigued by the idea of an all tube fuzz pedal for quite some time. I know that it probably is at least possible, at the basic level it should just be a bunch of cascading stages of preamp tube or a few. One of the DOD guys claims to have built one in the 60's when he was asked by a client to build a fuzz pedal and he hadn't realised that other builders were using transistors. I know a while ago Effectrode came out with the Mercury Tube Fuzz, but that's 'just' tubes driving a bunch of diodes.

The Friedman Fuzz Fiend has caught my eye. It's a discontinued product from Friedman (duh) and what remains of its presence on the internet isn't really illuminating. From the official Friedman YouTube video: "The tube delivers a natural feel, which compresses, clips and has more harmonics than any solid-state signal path pedal in production." This doesn't really say whether or not clipping diodes are employed here.

I would love to find schematics a gutshot of this thing to see what it really is doing inside. I suspect it's kind of like a Mercury Tube Fuzz, where the tube drives the signal into some diodes, but I'd be pleasantly surprised if that wasn't the case. Though, I can't see a single 12AX7 being enough to make to signal fuzz out on its own.

Any thoughts on this subject matter are welcome!

 

[Robert]

I haven't traced that one but I've traced the Motor City Drive. It does have two tube stages but there is also an opamp gain stage with LED clipping.

I'll see if I can get my hands on the fuzz.

 

[mzy12]

I haven't traced that one but I've traced the Motor City Drive. It does have two tube stages but there is also an opamp gain stage with LED clipping.

I'll see if I can get my hands on the fuzz.

Thanks for the input. There are some available on Reverb right now, all from the UK. I can't really justify spending the asking price on one of them just out of idle curiosity.

 

[Robert]

Nah, just hang in there a bit.

 

[Fuzzonaut]

tube fuzz pedal

Maybe @vigilante398 has something to add?

There was his Sashimi Fuzz.
"Sashimi Fuzz uses a 12AX7 running at high-voltage to blast through some germanium, resulting in killer fuzz tones. (...)."

I'd be down for a tube fuzz.

 

[mzy12]

Maybe @vigilante398 has something to add?

There was his Sashimi Fuzz.
"Sashimi Fuzz uses a 12AX7 running at high-voltage to blast through some germanium, resulting in killer fuzz tones. (...)."

That's certainly interesting! Is it like a two transistor topology then, but Q1 has been replaced with a tube?

 

[vigilante398]

Maybe @vigilante398 has something to add?

There was his Sashimi Fuzz.
"Sashimi Fuzz uses a 12AX7 running at high-voltage to blast through some germanium, resulting in killer fuzz tones. (...)."

I'd be down for a tube fuzz.

Sashimi was based on the Effectrode Mercury fuzz, which is basically just a tube overdrive with germanium and silicon clippers after it to make it sound more aggressive and fuzzy. I can throw the schematic up sometime if anyone wants to take a peek.

 

[mzy12]

Sashimi was based on the Effectrode Mercury fuzz, which is basically just a tube overdrive with germanium and silicon clippers after it to make it sound more aggressive and fuzzy. I can throw the schematic up sometime if anyone wants to take a peek.

That would be very cool of you! But unfortunately you don't have sub-miniature tubes forged under a waxing moon on an overcast July day, with germanium diodes made just so, while mercury was in retrograde, so honestly, how much of a fuzz is it really

 

[vigilante398]

That would be very cool of you! But unfortunately you don't have sub-miniature tubes forged under a waxing moon on an overcast July day, with germanium diodes made just so, while mercury was in retrograde, so honestly, how much of a fuzz is it really

The original Mercury uses 1N34a and 1N914 diodes for clippers, they weren't even going for unobtanium there lol. The tube they used is a 6948, but it has similar characteristics as 6N21B and 6N17B-V. I used a 12AX7 in mine because it's supposed to be dirty and 6948 only has an amplification factor of 70, compare to 12AX7's factor of 100.

 

[mzy12]

The original Mercury uses 1N34a and 1N914 diodes for clippers, they weren't even going for unobtanium there lol. The tube they used is a 6948, but it has similar characteristics as 6N21B and 6N17B-V. I used a 12AX7 in mine because it's supposed to be dirty and 6948 only has an amplification factor of 70, compare to 12AX7's factor of 100.

Haha sorry, I got carried away taking the mick out of marketing copy there I saw some of your PCBs available as kits on musikding and I was very impressed! I thought they looked very interesting. If you made your Lab Rat available there, I'd snap it up in heartbeat.

 

[Here I Go]

If your still interested.

It sounds ok, probably not the sound you imagine in your head though. It does sound monstrous with the rage engaged ( annoyingly a momentary switch ) but it does it by using a oscillator which kinda limits it to a gimmick.

I wish I knew enough to be able to mod it because I do feel there is a amazing sound in here somewhere. If I could somehow remove the oss. But retain the gain it introduces, I think it would sound great.

 

[vigilante398]

It does sound monstrous with the rage engaged but it does it by using a oscillator which kinda limits it to a gimmick.

What?

How does an oscillator increase gain?

 

[Here I Go]

oh, there’s got to be more circuitry involved then.

It’s what it sounds like when you hit the rage switch.

 

[vigilante398]

oh, there’s got to be more circuitry involved then.

It’s what it sounds like when you hit the rage switch.

Okay, I just watched the video linked above and now I'm bothered.

BUT FIRST, A DISCLAIMER
I have not traced this pedal, so any of my assumptions of how it operates are speculation from my limited experience with audio circuits, particularly tube circuits. Also anything negative I say about a builder of tube pedals should be taken in context as I am in the business of selling tube pedals.

Two traces on a circuit board will have what we call crosstalk, which is a type of electrical interference. The two main contributing factors of crosstalk in audio signals is the proximity of the traces on the board and the gain of the signals. The higher the gain of the circuit, the greater the distance required between the two traces in order to avoid this crosstalk. When there is enough crosstalk between the input of a gainstage and the output of the gainstage, this essentially forms a feedback loop, which will result in oscillation. This is part of why I design for 4-layer PCBs, it allows me to spread the traces out enough to avoid problems.

In watching the video of the fuzz fiend, it seems like what they're doing is just boosting the gain, the circuit is oscillating, and they're calling it a feature. So they're not artificially injecting oscillation, they're just cranking the gain super high and letting it do what it does then saying "oh yeah we meant to do that".

Anyway. I'll stop now.

 

[Robert]

the circuit is oscillating, and they're calling it a feature

You know how many wasted revisions I could have eliminated by learning this trick!?

"Quick, tell the guys in artwork to change the text above the Boost switch to Rage... we ain't trashing these PCBs"

 

[Here I Go]

I kinda understood what you wrote ( remember I don’t know anything about anything !! Heh)

But would a NE555P chip at the bottom be a clue ?

 

[vigilante398]

I kinda understood what you wrote ( remember I don’t know anything about anything !! Heh)

But would a NE555P chip at the bottom be a clue ?

Nope, the NE555 is part of the switched-mode power supply (SMPS) used to generate the high voltage for the tube from the 9-12VDC input.

 

[Here I Go]

I see, so my problem is even worse then I thought - it’s not a feature I can remove but a consequence !!

That is kinda lame

Well anyway - thanks for a bit of circuitry lore

 

[vigilante398]

I see, so my problem is even worse then I thought - it’s not a feature I can remove but a consequence !!

That is kinda lame

Well anyway - thanks for a bit of circuitry lore

I mean if you want to trace the schematic we can walk you through adjusting the gain so it doesn't oscillate, but unfortunately there isn't a lot else that can be done without redesigning the PCB with sufficient trace spacing to eliminate the oscillation.

 

[Here I Go]

Thanks for the offer but I think it’s more trouble then it’s worth to be honest.

I don’t want to waste your time - I don’t even like it much.

Cheers