Help with Roger Mayer Classic Fuzz!

[Foka]

Hello!

Well...I"ve finished my RM Classic Fuzz...but I had a little probelm:
All I got was CLEAN sound!!!!!

I've used the follow schematic!

http://www.geocities.com/j4_student/rmclassicfuzz.gif

Help-me please!!

Sorry for my english!

See you![/list][/list][/code]

[brett]

Hi check the connections for the 47uF (or is it a 4.7uF?) cap associated with the fuzz pot.  Check the fuzz pot wiper, too.

cheers

[Fret Wire]

First off, Welcome!

Did you use the 5k6 resistor value for Q1's collector, and 18k for Q2's collector? I don't see any way it will bias correctly with the 5.6k on Q1. With decent, low leakage transistors of the "normal gain range" it should bias up at around 25-30k on Q1, and about 13-18k on Q2. Those are ballpark values, they should get you close.

As Brett already said, check your soldering/wiring. I'm curious to hear how it sounds when you have it straight. I've always been curious about that specific schematic. It uses a 4.7uf input cap instead of a 2.2uf. A 47uf cap off Q2's emitter instead of 22uf. And a .1uf and .0022uf on the output instead of a .01uf. I'm curious about the vintage of the pedal that was traced from. Sometimes, schematics are posted from site to site without being verified. Drawing schematics off photos can be touchy too. I like schematics drawn from an actual pedal.

Here's a schematic for the Classic Fuzz that I drew from my own RM Classic Fuzz. It's an early model from when he was hand building them in NYC. The only differences between the RM Classic and the Dallas Arbiter ckt are the 1k output resistor, and the 2k pot. The 8k2 resistor off Q2's collector is increased to 18k for biasing reasons. If the 2.2k and 470k pot values seem odd, it's because they are Omeg pots (UK). Most others will be 2k and 500k, no noticeable difference.
http://aronnelson.com/gallery/Schematics-etc/RM_Classic_Fuzz?full=1

If you go to Geo's "Technology of the Fuzz Face" article, under "mods and magic", you'll see that RG's schematic of the "Mayer Mods" is inline with my actual pedal.
http://www.geofex.com/Article_Folders/fuzzface/fftech.htm

Mayer may have made changes to adjust for the quality of the transistors he was getting, but I don't know. I do know that in later Classic Fuzz models, he was using a trimpot on Q2's collector.

Let us know how you made out.

[MartyMart]

http://www.pbase.com/martymart/image/40091637
This is my original "Classic Fuzz"

Trimmer on Q1 is a 47k
I changed the output cap to a .068 and used a 2n2 to ground on the input.

Hope this helps.

Marty.

[barret77]

hey Marty

Sorry for my ignorance, but what's your board material (the white transparent)? Where do I get that?

thanks!

[MartyMart]

hey Marty

Sorry for my ignorance, but what's your board material (the white transparent)? Where do I get that?

thanks!

It's a Mayer "Original"  so thats not "my" board !!
I just posted the pic in the hopes of offering some help

Cheers,
Marty.

[Greg]

That schematic you're using as a reference was drawn up by me and Justin Philpott based on my Classic Fuzz. I bought it from North Star Audio around 1988. It sounded great for years and then suddenly went farty like the bias was way off. I was trying to figure out what was wrong so I was chatting w/ people like RG and Justin and since there were no schematics online of it, I had to trace it out in order for anyone to help. I eventually was able to get it sounding better but was never able to get it to sound like it originally did. Now it's a really bright fuzz. I believe I replaced a pot, replaced the tranny's (which I think I eventually determined was unneccessary) and put a trimmer or two into it. I never use it anymore but maybe I ought to dig it out and mess with it again.
I know this is really of no help but I just wanted to chime in about the schematic and where it came from. The component values, however weird they may seem, were correct for the pedal I have and it did sound great at one time.
Greg

[Fret Wire]

Hi Greg, nice to hear from the source of the schematic.  I always wondered where that schematic came from.
What does yours have on the bottom? Mine has the bare shiny plate with the Guitar Galaxy logo. They were the original distributor.

Appears there are at least three versions of the Classic Fuzz that were made. My schematic covers the early version (early eighties), your version probably came next (mid to late eighties?), then the trimpot version? I sent my schematic to Phillip Bryant at Fuzz Central, who posted it as the "early version". He also has your's/Justin's posted. I'm sure Tom Lanik from North Star could shed some light on the subject.

Marty, do you have the original values on yours? Do you know the vintage? Your's has the trimmer on Q1? Biasing by Q1's collector works fine also.

It would be nice to get all the versions plotted out once and for all.

[Foka]

Thanks a lot all of you!
After a quick review...I've found de problem: The conection of the AC128! :oops:

Well...I'm still having problems! I have the distortion sound...but it is intermittent! It's like the sound when you switch quickly the on/off button!!! :cry:
Can you understand?!?!?
I thought the problem is on the two AC128...I've took from an old electronic stuff that I have...In Brasil is very, very difficult to find some parts...and buy germanium transistors here , is like try to buy a flying saucer :wink: !!!

BTW...I have a little doubt:

The condenser that leaves the signal to the vol. pot. (according to the scheme) is connected on the battery's negative tension...is that correct???

Well...now I'm changing to the Vox TOne Bender...that uses silicon transistors... :wink:
As soon as possible...I'll post some pics and samples!!!!
Once again...Thanks a lot!!!

See you!

[RedHouse]

(not to hijack the thread but)....

Hey MartyMart,

I went to the link you posted above (http://www.pbase.com/martymart/image/40091637) and pressed the "Next" button to look at your other pics.

What board pattern did you use for the EZVibe in the pic http://www.pbase.com/martymart/image/40159130

Is it your own, or is there a trace pattern rolling around for that?

(edited typo)