Sunday, 30 March 2014

Roger Mayer Stone Fuzz


Edit: This circuit won't run properly with polarity reversed.

27 comments:

  1. A word from Roger Mayer:

    The Roger Mayer STONE FUZZ is is a modern evolution from the fuzz pedals I modified for Jimi. It is a very heavy sounding fuzz with roots that go back to the early fuzzes Jimi used but is not a clone of the old Fuzz Face.
    The STONE FUZZ maintains the guitars original tone characteristics with the open sound and sonic heritage that is the trademark of Jimi's recordings. I have added a few new features and advantages that will appeal to those players who strive for a modern sound with strong roots in the past. It has deliberately been designed with this is mind and is not a clone of an old design that duplicates the original faults and shortcomings.
    I have used the same basic transistor configuration but with several new innovations applied to the very basic circuit that was used then.
    The new Stone Fuzz is a very Low Noise high gain design, stable, free from radio and other electronic interference that cause so much trouble. It has a greatly increased output level that enables it to overdrive the front end of any amp as hard as you want with the Stone Fuzz set to produce virtually nil distortion in volume boosting mode.
    Turn up the Gain or Drive control and produce some of the deepest and tight low-end fuzz you have ever heard with the top end staying sweet encouraging soaring string bends and wild solos. The overall EQ has been carefully developed to produce a well-rounded fatness and musical tone, not the nasal or fizzy thin type of fuzz sound.
    The unit really comes into it's own during live performance situations as it cleans up superbly well using the guitar volume controland maintains the guitars original tone as the signal decays from wild distortion to original guitar tone. This unit can be effectively controlled from the guitar making life a great deal easier for the player who likes to change tone effortlessly.
    Because the circuit senses and uses electronic information directly from the guitars pickups to control it's own operational parameters it is recommended to use the Stone Fuzz 1st in the signal processing chain to take full advantage of this internal feedforward feature. It is this particular feature of the Stone Fuzz that helps to make it quite different from early fuzz pedals and makes the unit respond very well to each individual players touch, style and playing technique.
    Five minutes playing with the Stone Fuzz will convince anyone this is not just a re-hashed design but genuinely innovative with some new tone colours.

    The unit comes in the very rugged Rocket housing and features Hard Wire Bypass/True Bypass and an attractive and unusual Stone paint finish. It has two controls: Output Level, Drive or Gain and is powered by an internal 9 Volt battery with an operational life of over 150Hrs so changing a battery shouldn't be a problem.

    Sounds very good on paper.

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  2. My friend has a genuine one with Roger's signature and I've played with it for an hour or so. I can confirm that this is a good one and every fuzz face lover should at least give it a shot and see how you like it. Nothing as revolutionary as the description suggests but a very good sounding one.

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  3. I built the NPN version and even tried a few different transistors (BC550, BC549, 2N3093) and it sounds awful and nothing like the original. it's a splatty, heavily gated mess (even after adjusting the trimmer at all possible settings). i'm going to flip the caps, rewire the power supply and try PNP's in it next.

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    1. Strange. Layout is good. Only differences are the pot values that i rounded a bit (2K for 2K2 and 50K for 47K).
      http://analogguru.an.ohost.de/193/schematics/RogerMayer_StoneFuzz.gif
      AG has reference voltages on the schem..

      Let us know about any development.
      +m

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    2. yeah, I checked it against the schematic before I built it to make sure that your vero matched it and it definitely does. i'm putting ti on hold right now since i'm currently building a different pedal right now.

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    3. I built it up this morning and had the same experience. I assumed I had gone astray from the layout, but evidently not.

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    4. I have a strong feeling that there's an error in the schematic posted on FSB.

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    5. ...............either that or it takes a very specific BC559 to make it work properly.

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  4. okay, I messed around with it a lot more. with NPN's, I wired up an extrernal (bias) trimmer for Q2 and got it to sound a lot better, but I still wanted to try it with PNP's. so I wired it back to stock and since I don't have any BC559's, i tried it with BC307's and it sounded pretty good. I also tried 2N3906's and I think they were a bit better than the 307's. so, my conclusion thus far is that it works pretty well being PNP, but sucks when it's NPN. I have NO idea why, since it 'should' work either way, but somehow it doesn't.
    now i'm going to order some BC559's to see if it makes any improvement.

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    1. Now i'm quite puzzled as every other circuit works fine with polarity reversed. With Lazy Swamis having the same experience, i think i'll take the reversed NPN version down and tag this. I really want to know why it behaves like that as NPN, so if anyone has any insight on the matter, i'd be grateful....
      +m

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    2. I agee. I have no idea why either, and it should, but it just doesn't. I've tried BC307's, BC309's, BC560C's (all PNP's) and they all seem to work pretty well, but with the caps and voltage polarity reversed to run it as an NPN, 2N2222A's, 2N3904's, BC548B&C's, BC549B&C's,BC550B&C's all sound gated and splatty.

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    3. Yup. I'll remove the modded version from the file and tag it.

      Thanks for all the work John!
      +m

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    4. It is right to the schematic, but the 10K from supply to output cap/collector resistor junction seems huge to me. 30 times larger than the value used in a Fuzz Face.

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    5. Maybe that's where the PNP magic kicks in....
      +m

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    6. yep, IMO that 10K resistor was what caused all of the splatty-ness of the biasing of Q2 when it was NPN, but somehow it works fine with PNP's.

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    7. I sure would like to know what causes that :)
      +m

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    8. I remember reading a while ago that it was much easier to manufacture PNP transistors, and although it related to germaniums maybe the same is still at least partly true with silicon. I think some must certainly believe that PNP silicon give you something that you don't get from the NPN counterparts when you look at the Lovepedal Silicon Fuzzmaster for instance which could easily have been built with NPN transistors, but Sean opted for PNP with supply and ground swapped over for a negative ground.

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  5. Very odd. I breadboarded the NPN arrangement with BC549c last night and it sounds OK. Not spectacular, but no worse than manyof the myriad siicon fuzzface variants out there, and certainly not a splatty gated mess.

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    1. Now this is getting even more strange.. :) Could you probably take the components from your breadboard and try them on a strip? I know this is a lot to ask...
      +m

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    2. or maybe take some voltage readings on all three pins of the two transistors? at least that would be easier ;-).

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  6. Battery = 8.88v, Q1 collector trim set at 33k:

    Q1 e = 0v, b = 0.56v, c = 1.23
    Q2 e = 0.59v, b = 1.23v, c = 2.39v

    It's a little way off the voltages quoted on the schematic for the pnp, but not terrible. The trimmer allows you to almost reach the Q1c=1.37v, but the Q2c doesn't move much at all Listening again through headphones, it is actually a little gated on the decay of long notes, but not what I would call splatty (it's not what i would call a great fuzz sound though).

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    1. when I tried it with BC549C's it was awful. i'm running as PNP now with 560C's and I thin it sounds great.

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  7. I've just finished putting mine together using BC559C's - sounds pretty rough. I've adjusted the voltages as suggested but she's not as nice sounding as the video - I've used a 4k7 pot for the gain (as that was all I had handy), do you reckon this could account for it?

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    1. I bet that contributes to the issue. Try soldering a 2K2 resistor between lugs 2 & 3 of that pot to see if that helps.
      +m

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    2. Cheers - just tried that. Helps a little but those trannies sound harsh in this, not what I was hoping for, just like an average silicon FF :(
      Time to start swapping transistors! :)

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  8. Well I give up with this one - tried BC559, Bc557 and BC560 and they all sound like a rough silicon fuzz, nowhere near the sound on the vids. I get a "ripping velcro " sounding fuzz - good thing I have my faithful Arctic White Fuzz to fall back on ;)

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  9. Hi, I built my stone fuzz used bc559b,
    in my taste bias read :
    Q1 C=-1.3, B=-0.6, E=0v.
    Q2 C=-2.5, B=-1.3, E=-0.7.
    I like this fuzz sound, and one again..
    I love this blog~~ thanks for the vero layout.
    here some guts shot: https://goo.gl/photos/ji7UdC5A5WbD6vNX7

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