Guess what I'm making?

Steve Conner · 10-25-2009, 08:33 PM

With considerable help from RG Keen and Steve Daniels' FAQs, and a friend who sent me an assortment of germanium transistors.

Albert Kreuzer · 10-25-2009, 08:42 PM

mmh... Fuzz Face with Mullard OC44 and Telefunken(?) AC126!
Use CC resistors and carbon-zinc batteries for maximum mojo

Cheers,
Albert

Gypsey Eyes · 10-25-2009, 08:53 PM

nice. be sure to use a socket for the transistors for easy testing of different combinations. I found quite a lot of tonal variations with ones that look identical.

Chuck H · 10-26-2009, 06:58 AM

Something with silicooties...

Chuck

Sweetfinger · 10-26-2009, 07:10 AM

Oh dear! Say goodbye to hours, maybe days or weeks of your life. You'll end up red-eyed and crazy, scouring through junk heaps looking for '70's clock-radios that you can harvest the germanium output transistors from!

dai h. · 10-26-2009, 08:31 AM

makes more sense to buy a pre-sorted pair IMO. Old radios, tape players could be a source of small transformers which could be used as a pickup simulator cct. (see AMZ) to use with wah and fuzz. I highly recommend trying wah to buffer to PU sim. to fuzz. A wah'ed fuzz that works well sort of sounds like you fed the wah PCP and acid--magnifies the effect a (thousand?)fold.

Steve Conner · 10-26-2009, 09:34 AM

You guys saw right through me!

Of course it's a Fuzz Face. The transistors I used are just the two that tested best for leakage out of the whole lot. The OC44 has a gain of about 175, which makes for some real fiery distortion, but it does seem to clean up nicely with the guitar volume. To my ear it sounds better than with another AC128 in the front end. I was surprised to see that the AC128 is a portable radio output transistor with a rating of 1 amp, and probably a worse leakage spec than a small-signal device would have.

I got best results by turning the fuzz control up full and using the guitar volume to control the distortion. Turning the fuzz control down just made it sound crap, a swarm of mosquitoes trapped in a coffee grinder springs to mind.

Dai H: I take it by pickup simulator, you mean some sort of circuit that lets you connect a Fuzz Face after a wah pedal without it malfunctioning?

Sweetfinger: Been there, done that

Anyway, off to look for zinc-carbon batteries...

dai h. · 10-26-2009, 10:05 PM

steve,

the PU sim. is basically just an inductor from 2 to 3H (range to simulate typical inductance of a PU) with a variable R (to obtain the DCR). I don't quite understand it, but apparently the PU when connected to the FF becomes part of the circuit, and had something to do with achieving the "cleans up when vol. pot is turned down" behavior. The more "primitive" model apparently sometimes used is just the VR. The buffer is just a buffer to give the wah output low impedance drive, since I think the FF input is low making it difficult for a typical wah output to drive (which results in the wah effect not working very well with weakened effect sound and possible squealing). The buffer part I think is more important to get to the better working fuzz wah effect. Here's a pic of my experiment, an ordinary FET buffer and a couple of inductors (one from a wah, one unknown, one driver transformer from an old Sony cassette deck) in series. I couldn't measure them at the time, but after I bought an LCR meter I found I was within the target value (2.something Henries).

Guitar Pickups Simulation

imaradiostar · 10-27-2009, 01:01 PM

Um...I install a 22-47k resistor on the output leg of my wah pedal and now it works fine with my fuzz face.

Try it. I have historical reason to believe there was a similar fix for Jimi.

jamie

dai h. · 10-27-2009, 09:11 PM

right, well I'm glad that works for you but if you read above, use of a resistance was mentioned.

The more "primitive" model apparently sometimes used is just the VR.

fwiw the Fulltone '69 (their version of a FF) uses a 50k VR at the input so maybe wah interaction is part of the reason.

booj · 10-29-2009, 01:57 PM

Quote:

I got best results by turning the fuzz control up full and using the guitar volume to control the distortion. Turning the fuzz control down just made it sound crap, a swarm of mosquitoes trapped in a coffee grinder springs to mind.

That's one thing I spent days and weeks on. Came up with putting a 2.2uf in series with (about) a 100 ohm resistor from the "hot" lug of the gain control to the wiper. Then, when the gain is turned own, you don't lose high end.

imaradiostar · 10-30-2009, 03:50 AM

Quote:

Originally Posted by dai h.

right, well I'm glad that works for you but if you read above, use of a resistance was mentioned.

The more "primitive" model apparently sometimes used is just the VR.

fwiw the Fulltone '69 (their version of a FF) uses a 50k VR at the input so maybe wah interaction is part of the reason.

I'm sorry man, I missed it. It looks like you've got a logical solution.

The fuzz face is a pretty neat circuit- it does so much with so little but it's so sensitive to different parts and inputs!

jamie

10-25-2009, 08:33 PM	#1
Steve Conner Supporting Member Join Date: May 2006 Location: Glasgow, Scotland Posts: 2,992	Guess what I'm making? With considerable help from RG Keen and Steve Daniels' FAQs, and a friend who sent me an assortment of germanium transistors. __________________ "Ohhhh miracle bulb shines feebly"

10-26-2009, 09:34 AM	#7
Steve Conner Supporting Member Join Date: May 2006 Location: Glasgow, Scotland Posts: 2,992	You guys saw right through me! Of course it's a Fuzz Face. The transistors I used are just the two that tested best for leakage out of the whole lot. The OC44 has a gain of about 175, which makes for some real fiery distortion, but it does seem to clean up nicely with the guitar volume. To my ear it sounds better than with another AC128 in the front end. I was surprised to see that the AC128 is a portable radio output transistor with a rating of 1 amp, and probably a worse leakage spec than a small-signal device would have. I got best results by turning the fuzz control up full and using the guitar volume to control the distortion. Turning the fuzz control down just made it sound crap, a swarm of mosquitoes trapped in a coffee grinder springs to mind. Dai H: I take it by pickup simulator, you mean some sort of circuit that lets you connect a Fuzz Face after a wah pedal without it malfunctioning? Sweetfinger: Been there, done that Anyway, off to look for zinc-carbon batteries... __________________ "Ohhhh miracle bulb shines feebly"

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10-25-2009, 08:42 PM	#2
Albert Kreuzer Senior Member Join Date: May 2006 Posts: 287	mmh... Fuzz Face with Mullard OC44 and Telefunken(?) AC126! Use CC resistors and carbon-zinc batteries for maximum mojo Cheers, Albert

10-25-2009, 08:53 PM	#3
Gypsey Eyes Junior Member Join Date: Oct 2009 Posts: 16	nice. be sure to use a socket for the transistors for easy testing of different combinations. I found quite a lot of tonal variations with ones that look identical.

10-26-2009, 06:58 AM	#4
Chuck H Old Timer Join Date: May 2007 Location: pacific north west Posts: 1,482	Something with silicooties... Chuck

10-26-2009, 07:10 AM	#5
Sweetfinger Senior Member Join Date: May 2006 Location: Phoenix Posts: 408	Oh dear! Say goodbye to hours, maybe days or weeks of your life. You'll end up red-eyed and crazy, scouring through junk heaps looking for '70's clock-radios that you can harvest the germanium output transistors from!

10-26-2009, 08:31 AM	#6
dai h. Senior Member Join Date: May 2006 Posts: 777	makes more sense to buy a pre-sorted pair IMO. Old radios, tape players could be a source of small transformers which could be used as a pickup simulator cct. (see AMZ) to use with wah and fuzz. I highly recommend trying wah to buffer to PU sim. to fuzz. A wah'ed fuzz that works well sort of sounds like you fed the wah PCP and acid--magnifies the effect a (thousand?)fold.

10-27-2009, 01:01 PM	#9
imaradiostar Senior Member Join Date: Jan 2008 Location: Doylestown, PA Posts: 275 Member's Picture Albums	Um...I install a 22-47k resistor on the output leg of my wah pedal and now it works fine with my fuzz face. Try it. I have historical reason to believe there was a similar fix for Jimi. jamie

10-27-2009, 09:11 PM	#10
dai h. Senior Member Join Date: May 2006 Posts: 777	right, well I'm glad that works for you but if you read above, use of a resistance was mentioned. The more "primitive" model apparently sometimes used is just the VR. fwiw the Fulltone '69 (their version of a FF) uses a 50k VR at the input so maybe wah interaction is part of the reason.

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