Question for Fuzz Face experts

Discussion in 'Burnt Fingers DIY Effects' started by coldengray, Jan 3, 2019.

  1. coldengray

    coldengray Tele-Meister

    Age:
    43
    Posts:
    408
    Joined:
    Sep 30, 2009
    Location:
    Charlotte, NC
    I have been eyeing this Fuzz Face
    PCB from Aion FX:

    https://aionelectronics.com/project/solaris-fuzz-face/

    My question is this: can I substitute Silicone for Germanium without any other changes? The Project Overview says you can build the pedal with Ge or Si but the build docs don’t mention Si anywhere. I’m a total rookie at this stuff so I have no idea. Thanks!
     
  2. luckett

    luckett Banned

    Posts:
    3,614
    Joined:
    Jun 14, 2011
    Location:
    .
    You can swap si and ge, but you may have to make changes to get it to bias the same.
     
  3. Suproman

    Suproman Tele-Holic

    Posts:
    524
    Joined:
    Feb 23, 2006
    Location:
    Ottawa, ON, Canada
    Looking at the schematic, they have a trimpot on the board to adjust the bias for the second transistor, so you might be ok with silicon or germanium transistors.
     
    coldengray likes this.
  4. sirbergersworth

    sirbergersworth Tele-Holic

    Posts:
    560
    Joined:
    Aug 30, 2011
    Location:
    St. Louis, MO
    All depends on if the ge it si are both pnp or npn.


    Sent from my iPhone using Tapatalk
     
  5. sirbergersworth

    sirbergersworth Tele-Holic

    Posts:
    560
    Joined:
    Aug 30, 2011
    Location:
    St. Louis, MO
    What board are you building it on?


    Sent from my iPhone using Tapatalk
     
  6. coldengray

    coldengray Tele-Meister

    Age:
    43
    Posts:
    408
    Joined:
    Sep 30, 2009
    Location:
    Charlotte, NC
    Aion FX Solaris Fuzz. It has all the tweaking knobs I want for a fuzz face and I have a bag of BC109C transistors here ready to roll. I have a good Germanium Fuzz Face already so want to build the ultimate Si Fuzz Face for my needs.
     
  7. Chunkocaster

    Chunkocaster Poster Extraordinaire

    Posts:
    9,725
    Joined:
    Aug 10, 2018
    Location:
    In space with Ziggy
    I miss my favourite Fuzz Face pedal. It was one of the older large red germanium versions that just stopped working after plugging into it the wrong way around one day. Guessing it fried something although I don't understand why that would happen.

    There are a few hand wired clone micro boards available on ebay using vintage components. Might be worth buying one and dropping it in the pedal as a replacement. At $50 bucks it seems like a decent option.
     
  8. awasson

    awasson Poster Extraordinaire

    Age:
    57
    Posts:
    5,697
    Joined:
    Nov 18, 2010
    Location:
    Vancouver
    BC109C’s are a nice transistor for a Fuzzface. I’ve got them in one of mine and I like it a lot.
     
  9. Suproman

    Suproman Tele-Holic

    Posts:
    524
    Joined:
    Feb 23, 2006
    Location:
    Ottawa, ON, Canada
    I would suggest installing sockets for the transistors, then you can try them out and select the ones that sound best to you.
     
    zippofan and awasson like this.
  10. waparker4

    waparker4 Doctor of Teleocity Ad Free Member

    Posts:
    18,996
    Joined:
    Nov 9, 2011
    Location:
    Philadelphia, PA
    "Project overview

    The Solaris Fuzz project is the ultimate clone of the Dallas-Arbiter Fuzz Face, one of the most ubiquitous effects in the DIY and boutique effect landscape. While the original Fuzz Face is a very simple circuit, many modifications have been made in the nearly 50 years since it was first introduced.

    This PCB will allow you to build with germanium or silicon transistors (or a hybrid like Joe Gagan’s Easy Face), positive or negative ground, the original two knobs or as many as five. It also incorporates an optional charge pump, allowing you to use a standard 9v center-negative power supply while still using PNP germanium transistors."


    Don't do the optional charge pump for PNP transistors.
     
  11. memiller

    memiller Tele-Meister

    Age:
    41
    Posts:
    107
    Joined:
    Jan 9, 2019
    Location:
    Texas
    The FF circuit is simple but super finicky when it comes to getting the "classic" FF tone. The issue you run into is that Si transistors are just way higher gain than Ge. This can lead to a harsher than desired tone, but depending on a number of other factors may be perfectly fine. As long as you're cool with that... yeah, swap away. Like the guy above said, socket the things so you can swap a few in and out.

    The other issue is adjusting the bias since Si and Ge need different juice buuuuut it looks like this PCB incorporates a lovely little bias knob so you have absolutely nothing to worry about. This is actually a pretty straightforward and difficult to screw up build. Neat.
     
    Paul-T and coldengray like this.
  12. Paul-T

    Paul-T Tele-Holic

    Posts:
    647
    Joined:
    Nov 23, 2018
    Location:
    London
    It will be interesting to see what you think to the silicon version.Please report back!

    I've just gone the other way, I have an 80s silicon fuzzface and just fitted the pigeonfx repro board with CV7001 germanium. But of course I've kept the old board, maybe I'll put that one in an enclosure.

    If you're looking for an old school board, the pigeonfx one seems to be the best.


    Finished.jpg
     
  13. 11 Gauge

    11 Gauge Doctor of Teleocity

    Posts:
    12,391
    Joined:
    Mar 21, 2003
    Location:
    Near BWI Int'l
    If you use the silicon transistors in the Axis Face, then the gains are similar.

    Just FYI (if you don't want to investigate the link above), the transistors to use are:
    • Q1 - PN2369A (hFE 40-120)
    • Q2 - BD139 (hFE ~130)
    ...Both of those are common NPN silicon transistors, so that makes things nice and easy for Fuzz Face tweaking and experimenting.

    FWIW, if you aren't totally sold on using silicon transistors, I think it's worth it to build an Easy Face. It uses a (common) silicon transistor for Q1 (PNP 2N3906), with a germanium (2SB33) transistor for Q2. The Easy Face reveals that much of the magic is only to be found in Q2, thereby cutting in half the trouble of sourcing, sorting, and testing for leakage germanium transistors.

    IME, even silicon transistors with moderate gains can provide some nice sounds in a Fuzz Face, but the bigger issue is really just softening some of the upper frequencies, and smoothing out the clean sound that you get when you roll down your guitar's volume (e.g. gets way too bright too fast).

    ...To achieve the above, you have a few different options. You can put a cap parallel to the negative feedback resistor (the one that's typically 100K), to "globally" soften the top end. Or, you can put small caps across the base and collector of each transistor (the Axis Face has a 100pF cap across the B&C of Q2). IME, a cap across the B&C of Q1 is a bit harder to tweak the value of, because if it's too big, you lose too much top end detail, and if it's not big enough, it has no real useful effect.

    I have a love/hate relationship with the Fuzz Face. That said, the ones I like the most are super-tweaked silicon types. Once you get one dialed in, IMO it will run circles around the best germanium ones, and be a lot more flexible, AND be 100% consistent in performance (e.g. none of the issues experienced with germanium transistors, ever).

    Also, IMO, I think most users will really find the pre-gain or smooth types of controls with the Easy Face, Axis Face, etc. to be super useful. Some folks think it tends to be adjustable than the actual fuzz control on a Fuzz Face. For those who don't know, the pre-gain/smooth control is basically how the fuzz is adjusted on the Jordan Bosstone.
     
    Last edited: Mar 19, 2019
    awasson, Obelisk and Iago like this.
  14. mictester

    mictester TDPRI Member

    Posts:
    24
    Joined:
    Jul 2, 2017
    Location:
    East Anglia, UK
    11 Gauge has covered most of the things that I would have suggested. A Fuzz Face with high gain transistors (like your BC109C - which are nicely low noise, by the way) can be great fun, but doesn't sound anything like a "vintage" one. For that, you need low gain devices and the base to collector capacitors get rid of the "fizziness". If you do it right, it'll be indistinguishable from a "magic" 60s germanium one, except it won't need the correctly run down battery and the right room temperature to get "that" sound! The ideal hFE that I've found is around 50 - 60 for the first transistor, and around 70 - 80 for the second, but YMMV.

    One thing I've done with success is to use the transistors in a CA3049 transistor array IC. There are five pretty low gain transistors in the package, so I've built a Fuzz Face with two of them, and used the remaining three for another Fuzz, with two footswitches to select them! Incidentally - if you ever want to build a "Standard Fuzz" (the 70s Japanese circuit with five transistors which gives a lot of octave), the 3049 gives you the "long-tailed pair" with very accurately matched devices!
     
  15. Obelisk

    Obelisk Tele-Afflicted

    Posts:
    1,393
    Joined:
    Apr 1, 2013
    Location:
    NW USA
    I don't build, but absolutely concur with your assertion. I actually don't get much of the hype about germanium transistors unless you love your fuzz flubby and tubby. I have about 3 dozen fuzz pedals. Most of them are silicon based. My favorite of the Fuzz Face clones is the one in my FoxRox Captain Coconut. It has a Hot Silicon card in it and it just rages. The hot silicon card cleans up better with volume pot down than the stock germanium card plus it works better when used with humbucker pickups.
     
  16. awasson

    awasson Poster Extraordinaire

    Age:
    57
    Posts:
    5,697
    Joined:
    Nov 18, 2010
    Location:
    Vancouver
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.