Sunday, 14 February 2010

Roger Mayer Axis Fuzz


and modified version removing the 220R resistor and 1nF cap.  Some people think it sounds better:

38 comments:

  1. Hey would you by any chance know the brands roger mayer used for the two transistors.

    The 2N3904 and 2N3906, were they Siemens, or Panasonic?

    And if you know the brands of the other parts that would be great. Thanks so much what a great site.

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  2. Sorry I have no idea whatsoever. I did the layout from a schematic at Fuzz Central, so you may find more information there.

    Thanks for the compliment on the site :o)

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  3. Hi Mark, on this particular one, what would you recommend for the 470pF cap, a ceramic one or a silver mica? thanks!

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    1. Just use what you've got. I have full sets of ceramic, silver mica and ceramic multilayer caps and I'd be happy to use any of them. I do try to avoid standard ceramics much of the time, but I think their usual disadvantages can actually be quite welcome when using them in some fuzz circuits.

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  4. thanks! on this design, that 470pF capacitor is there for bypassing radio frequencies to ground?

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    1. It probably isn't going to make a huge amount of difference then.

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    2. I don't know, it was a question, sorry for that!
      I should have said: Is that 470pF there for bypassing radio frequencies to ground?...

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    3. Could be. It's a filter of some description although if it was specifically for RF I would have thought it would have been at the input with the pulldown resistor rather than after the input capacitor. But it certainly could have been included with that in mind.

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  6. Almost there
    http://flic.kr/p/dqZ49e

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  7. Any chance of a regular vero layout for this one?
    I breadboarded it (from the schematic on fuzzcentral) and it sounds nice. :)

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  8. I made my own vero up for it and it sounds great. here's my verified vero for it:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/RogerMayer/Axis_Vero_V2.png

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    1. Great stuff, thanks for that John

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    2. Actually, I think there's a flaw in the vero. I put it together and only got a really blatty, very nearly dead 9volt tone out of it until I switched drive 2 lug to drive 3 and placed a wire from drive 2 lug to the spot just below Volume 3. That's when I was able to get a solid tone out of it. I'll post a revamped version in a bit.

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  9. http://i189.photobucket.com/albums/z230/ericandleslie/Axis_Vero_V3_zpsef4c7da9.jpg

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  10. did you use the latest layout?
    this one works perfect:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/RogerMayer/Axis_Vero_V2.png

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  11. yeah. That's the one I modified. Initially it didn't work so well. I'll check the board but, it just sounded dead, no offense. I noticed when I tested the connections that when I touched on where I put lug 2 of the drive, the fuzz came on full blast. It was more Muff sounding than I had expected.

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    1. well, my vero (and IvIark's tagboard) follows and matches all of the posted schematics that I've seen. like this one:

      http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/RogerMayer/RogerMayerAxisFuzz.jpg

      my build of it sounds great. some people like to use a 25-50K trimmer for the 22K resistor for the collector on Q2 to dial it in even further, but that's the only mod besides an added tone control for it that I've seen. BTW, this one is not supposed to be a muff sounding fuzz.

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    2. So weird. I'll rebuild as I'm sure I missed something. What are the voltages on the transistors supposed to be? Also, I had to combine, in series, a couple of resistors to get the 680k and the 820k which resulted in the 820k being 810k. I also used a 1kv .001 uf cap for the 1n, without a socket. Question - why the socket for that? Is it to be able to swap out with a different size at will? I like the idea.

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    3. the socket for the 1n cap is so that as an option, you can just remove it. alot of people prefer it without the 220R/1n in the circuit so if you remove the 1n, the 220R has no effect. I run mine without it.

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  12. Absolute apologies to you, John. I finally got it to work correctly. I guess I has some bad resistors and caps in there. Question, when I dial down the guitar volume, is it supposed to sound like an overdrive (sort of)?

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    1. no prob.
      yeah, it'll be more like an overdrive with the instrument's volume down but this one is pretty much a fuzz overall.

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  13. I also found that matching the hfe's on the transistors makes it sound better (since it removes the fizzy decay). my 2N3906 measures 232 and I'm now using a 2N2222A for the 2N3904 which measures 234.

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  15. Hi I built this one recently from John Kallas' layout above and it sounds great, but does anybody know how to modify the circuit to increase the gain? With my guitar volume down it sounds really good and gnarly and dynamic (great for playing the riff for Hear My Train A Comin) but I just want more gain for the solo.
    Anyway, thanks for your great site and I hope you are able to get going again soon with more layouts. Peace :)

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    1. I'd probably just say audition a few transistors and see which ones sound best? They have the most control over the gain of the circuit I think.

      Maybe have a read through this thread for tips http://www.diystompboxes.com/smfforum/index.php?topic=27144.0;nowap

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    2. Hi sorry for taking such a long time to reply. I've only just started working on my Axis Fuzz again, and the info in that link is really useful, thank you :)

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  16. Hi, one source tell about hfe in axis stock, Q1 118 and Q2 158.
    It's hard to find 2N3906 and 2N904 in this range so piggyback it!!
    I did it and get Q1 110 and Q2 140 and it sound (I feel) close to original now,
    much more manageable and usable in all the fuzz pot range without excess or bad decay!
    Use the tone pot on your guitar to control the high end like the volume for the fuzz, dark fuzz and perfect bright clean accessible to a single hand! This awesome circuit.
    Thanks so much guys

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  17. Hi folks
    I look forward to assemble this. However, someone may suggest how add a tone knob to the schematic please?

    Thanks in advance
    Guido

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    1. Take a look there:
      http://www.tdpri.com/threads/axis-fuzz.290945/

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  18. Hi all, i really would like making this fuzz, but
    how may i plug the footswitch? it's not mentioned
    Thank you

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    1. hi greg. i'm under the assumption that this is your first build. before you do anything read the build guide, seen at the top, before building anything. it will explain how to build an effect.

      not to answer your question about the switch wiring. if you look at the top there is a tab labeled, offboard. this will show you how to wire nearly all effects. since it's the same in 95% of all pedals you won't see the switch wiring for any layouts, because it's redundant and a waste of time to put in every layout.

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  19. Hi Zach, yes you're right, that'll be my first build haaa,
    Indeed, this is often the same wiring, i found it after posting !!
    Thank you for answering.

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