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Friday, June 19, 2015

Vox ToneBender Mk I

You might look at this and think, "Gee, it's just another Fuzz Face," when in actuality, this pedal pre-dates the famous Dallas Arbiter stombox. (This is different from the Sola Sound ToneBender Mk I, as the Sola Sound has 3 transistors.) It was made in Italy for Vox and sounds like a Rangemaster and Fuzz Face combined, due to its smaller input and output capacitors. This is also the same circuit as the D*A*M 1966 Italian Tone Bender. I've added a 10k trimmer in place of the stock 8.2k resistor to dial in the bias for Q2 (a 20k trimmer might give you more tweakability), but on the PCB there are pads for a resistor in place of the trimmer if you prefer to go that route. Also, I've added a pull down resistor at the input, and polarity protection and power filtering. Note that this was originally built with PNP germanium transistors and was positive ground. The perf side of the layout reflects this, while the PCB side reflects negative ground for use with NPN transistors.




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17 comments:

  1. RyanDecember 24, 2015 at 4:13 PM

    I have this built up now using Germanium AC128s.

    This part in the description confuses me:

    Note that this was originally built with PNP germanium transistors and was positive ground. The perf side of the layout reflects this, while the PCB side reflects negative ground for use with NPN transistors.

    I am using the PCB layout.

    Pedal is very quiet with no fuzz. Should I switch to NPN transistors? If so, any suggestions?

    Thanks, and happy holidays!

    ReplyDelete
  2. UnknownDecember 24, 2015 at 4:53 PM

    Hi Ryan,
    Yes, I believe that you should be using an NPN. Your ac128 is a PNP which would work if you made this using the perfboard layout above. The PCB version needs an NPN. Good luck.

    ReplyDelete
  3. RyanDecember 24, 2015 at 4:59 PM

    Thanks Bud.

    ReplyDelete
  4. UnknownDecember 28, 2015 at 12:47 PM

    I can verify this one. Built with AC187K NPN transistors.

    ReplyDelete
  5. c.frenchMay 31, 2016 at 1:18 AM

    Hello!
    I just finished building the perfboard version. no dice. all i get is the same sound as when the circuit is bypassed. it's baffling...
    Anyone have an idea?

    Thanks in advance!

    Chuck

    ReplyDelete
    Replies
    1. c.frenchJune 5, 2016 at 2:57 AM

      figured it out! it was b/c i've been testing it with a negative ground test box (duh!) this thing sounds rad! thankyou for this awesome blog!!

      Chuck

      Delete
  6. yeahs4June 18, 2016 at 5:47 PM

    what happend if I use a 10 uf or any other value instead of de 47uf cap?

    ReplyDelete
  7. Effects LayoutsJune 18, 2016 at 5:57 PM

    The 47u cap is for power filtering. I wouldn't go much lower than 22u if you're substituting. 100u is another common value for power filtering caps.

    ReplyDelete
  8. pete_gSeptember 28, 2016 at 11:17 AM

    This comment has been removed by the author.

    ReplyDelete
  9. pete_gSeptember 28, 2016 at 11:48 PM

    Do those extra power filtering caps change the values of the other caps and affect the sound, or are they there for providing constant power through the line?

    ReplyDelete
    Replies
    1. Effects LayoutsSeptember 29, 2016 at 7:15 AM

      Doesn't affect the sound. Just smoothes the power to make it more consistent

      Delete
  10. Ramón HerverFebruary 23, 2017 at 3:19 AM

    Hi!! The resistor in the lug 3 of the fuzz pot is 47k or 100k? Thanks buddy!

    ReplyDelete
  11. UnknownMarch 22, 2021 at 3:31 PM

    what transistors should i use?

    ReplyDelete
  12. James JJune 26, 2021 at 11:23 PM

    I mistakenly built this with the idea that it was Negative Ground. It's what I get for not reading all the information beforehand. I used the PERF picture, built it, and (after realizing my mistake) reversed the Electrolytic capacitors and the Diode like the top right picture, used 2 NPN transistors and it works great. I didn't have a B1K lying around for the Fuzz so I used a B5K.

    ReplyDelete
  13. ClassicFuzzSeptember 11, 2021 at 3:37 PM

    Is there a possibility to add the Super Bee Switch to this layout?

    ReplyDelete
  14. DiegoSeptember 19, 2023 at 3:08 PM

    Hello! I built the fuzz based on the PCB image, and it sounds wonderful, but the fuzz control doesn't work. How can I fix it? Thank you very much!

    ReplyDelete