Tonebender Mk 3 report

[brianwenz]

Hello Hello---
          Good, now I don't have to post my Solasound pic!
Hey Stu--- where did  Sola put the MK IV   designation on that pedal??   Is it on the inside or written somewhere on the case???
Brian.

[petemoore]

  Awesome Pic Stuart !!!
  Cool knobs !!
  Large boxes.

[brian wenz]

Hello Hello--
     Hhhmmmmm..... looks like old "hit-and-run" Stu has left us again!   Baits us with the great pic and then buggers off!
Brian.

[Stuart]

LOL!  The MkIV designation is above the foot switch.  That one's on loan, but the rest are mine 

[brian wenz]

Hello Hello--
   Thanks Stu!
   If you're still there....... what circuit is in that MKIV?   
same as the 3-knobber???
Brian.

[Ge_Whiz]

Note in Stuart's picture the arrangement of the 'Instrument' and 'Amplifier' sockets. That's how I remember my old (stolen) Fuzz Face, so when I built my germanium FF some years ago, that's how I arranged the input and output. Drove my chum nuts when I lent it to him - "I spent 30 minutes trying to get it to work!" he cried. "I had the jacks the wrong way round!". I did point out that I had labelled them clearly, but he didn't want to acknowledge that. Ever since, I've arranged then as IN - right, OUT - left, which does keep leads out of the way of a clumsy right-handed guitarist like me.

[brian wenz]

Hello Hello--
    GE-- Yep, that's also a quick way to tell a Colorsound reissue pedal from an original......the input is always on the right  [looking down on the pedal with the knobs at the front].
Brian.

[Stuart]

Hello Hello--
   Thanks Stu!
   If you're still there....... what circuit is in that MKIV?   
same as the 3-knobber???
Brian.

A few tweaks, but yes, basically the same.  The first MkIVs had the "upside down" board like the MKIII, then they went to the normal style board during 1970, as far as I can tell.  Early 3-knobs, at least up to mid-late '71, have 680K/100K bias string resistors instead of the later 220K/47K.  The bypass cap on the 3K3 resistor was 10µF or 6.4µF.

[petemoore]

  This one's next up, I have perf, will build it...
  I'll socket and see if I can 'sneak' an SI transistor in Q2...and still have it sound as good as a '3 Ge TB'.
  Interesting is the Botique 3 Knob Bender, the 500k pot [and 10k stop R] coming off the collector and to the emitter...that's the 'major change' I noted between a TB and a B.TB, not sure what it does, can be added/subtracted easily enough...
  I love my 2 knob TB, but it's best set 'rough' and I haven't been able to use it with other 'cleaner' effects...best left on [IMO for the most part] by itself because the transition from on to off / off to on, is 'abrupt', of course the guitar rolloff makes fairly good 'mild cleanup' of the distortion.

[brian wenz]

Hello Hello--
        I really like the 3-Knob circuit...plenty of fuzz and more tone options then the MKII.
Brian.

[petemoore]

  Any recommendations for gain?
  Q1 and Q2 being Darlington configured, I would imagine high gainers work well there, I can't look right now, but imagine gain for these are set by the resistors.
  Q3...?
  Low leakage is always better.
  Board is small and looks real good, hopefully I'll get to trying it out with transistors tomorrow.
 

[Steben]

Q3 only works with leakage.

[jmusser]

I still didn't get a reply on the "Park" designation! I finally got my Russian germanium PNPs in, so I should be getting my 3 knobber together before long.

[nightingale]

Q3 only works with leakage.

Seriously?
I have had an all germ.  NPN one for a couple years now.. i dropped some low gain si [2N2369] into the Q1/Q2 darlington positions, and the fuzz is really bad and gatey sounding now? I must need to rebias Q3 now? I will post back after I get it sounding OK with the Si tranny's.

[Steben]

You should rebias Q1 and Q2 I guess Check the collector voltages.

With Sillies at Q3, the base would be really at 0 Volts, like it should be in theory, giving only a part of the positive waveform. But with Germs, the base gets juiced a bit through leakage, giving some needed bias, still very assymetric though.

[nightingale]

You should rebias Q1 and Q2 I guess Check the collector voltages.

Will do,
Since I have the fixed resistors soldered in, I might do the opposite and plug in different Trannys to get the right voltages?
I wish I would have measured the the Hfe of the germ Trannys I had in Q1/Q2 before I lost track of them? This thing used to sound real nice!
I will post my results!
Thanks!
I was not aware of leakage adding to the mystique of this circuit?

[brian wenz]

Hello Hello--
    JMusser--
          Park was the name Marshall used for it's  "budget" line of gear [amps, etc.]  Sola made the Marshall Supa Fuzz [variation of the TB MKII] and also the Park unit [variation of the 3-knob].  Some of the Park fuzzes had no fuzz control......the fuzz was full-up all the time!
    Hey Ryan!!-- How are you doing??  Haven't talked to you in a while...
Brian.

[jmusser]

Thanks Brian. I have seen the "Park" fuzz schematic somewhere, and wondered where it came from. Is the Lawn Box another knock off of the Tone Bender too? It seems like someome made a reference to the Tone Bender circuit and the Lawn Box once upon a time.

[nightingale]

    Hey Ryan!!-- How are you doing??  Haven't talked to you in a while...
Brian.

sent you a PM..

[Ge_Whiz]

No real 'mystique' to leakage. With most silicon transistor stages, you'll see a bias resistor of quite high value running from base to collector. This was commonly omitted from germanium circuits, since there was often enough internal current leakage to do the same job. Of course, 'inadequate' leakage could cause 'undesirable' distortion in most applications, but 'desirable' in a fuzz box.