Tonebender tranny?

[bob barcus]

I have a 1991 Vox PNP Tonebender can someone tell me about AC4004 trannys and I want to change the .15uf? with a 2.2 uf Cap like a FF

[azrael]

Never heard of that Tranny.

Exactly which Tonebender do you have? What tonebender has that size of input cap?

[petemoore]

I have a 1991 Vox PNP Tonebender can someone tell me about AC4004 trannys
  Tonebenders originally used Ge transistors, assuming it's a Ge, it will probably vary greatly in usability and Hfe/Leakage, like other Ge transistors.
  Sticking it in a DMM hfe checker socket 'every which way' until a ballpark looking number appears in the readout for Hfe and leakage measured, will tell whether it's PNP or NPN, for leakage and suitability in small signal circuits, RG's circuit which allows leakage and Hfe to be calculated [at GEO] is recommended to select usable transistors for Tonebender/Rm/FF type circuits.
  If basic TB circuit, Q1 should have some leakage, Q's 2 and 3 are of Fuzzface circuit and should be low leakage with 'low-ish' gains, Q1 lower gain than Q2.
  and I want to change the .15uf? with a 2.2 uf Cap like a FF
  Tap the input [where the input cap and the first transistor base connect], and run that to the switch through your chosen value capacitor, perhaps a switch between 2 different value caps ? [recommend choosing a circuit that defaults to X value when switch breaks, instead of A/B wiring which would cause a signal block]. Paralleling 1 cap 'on' the other through a switch means when the switch dies, the one [small value compared to the parallel caps value] cap still is hardwired.
  Or series with the switch jumpering the second capacitor, if the switch breaks open then then both caps are hardwire to large default value.

[DNomis]

The easiest way to tell if a transistor is Si or Ge,is to use a multimeter set to the diode test function,to measure the b-e voltage of the transistor,Si transistors will read from .5 to .8 V,Ge transistors will read from .1 to .3 V...hope that helps....

[zombiwoof]

I believe he's talking about the reissue Vox Tonebender that came out back then.  I bought one new at the time, but didn't like it because, first of all it didn't sound like an original ToneBender I had previously had, and secondly the whole pedal was microphonic, when you clicked it on the case of the pedal magnified noise when it was touched by anything.  I sent it back and got the Dunlop FF I have today (which is now modified to sound like a real Fuzz Face).  I don't know what those trannies were in the RI Tonebenders, I didn't know anything about pedal stuff when I had mine.

Al

[petemoore]

  Yepp, now that you mention it' it sounds like mention of the RI I heard before.
  The RI's aren't like the originals, the transistors are...whatever they are...
  I guess they work' at least.
  TB tone isn't by any means a plug 'n play by way of stick the parts together and it'll rock [prehaps with extreme luck].
  Same thing pretty much goes for the very widely varied and popular FF circuit.
  To get ''that-right" requires many things work as integral components to the overall tone produced.
  That'' varies greatly from player to amp and guitar.
  "Right" also varies greatly.
  Wierd bias, or even the wrong Q gains, or input cap value or gain setting can make wide variety of circuit behaviours.
  A good way get your' Tonbender tone bent just right on another Perf-bread circuit board [or breadboard or other], then graft that circuit into the pedal.
  Whether a solid working circuit can be grafted to the existing board is option to assess the possibility before proceeding.
  To figure and/or reconfigure, having the transistor pre-tested [measured for preferred leakage and Hfe] or 'un-fixed' is preferred. With the transistors soldered in it makes analysis of their 'ge's for effects goodness' rather...difficult.