The Final word on the Sola Sound Tone Bender!!

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11/20/1999 2:40 AM

John Catto

The Final word on the Sola Sound Tone Bender!! Today a friend of mine gave me a (not working - broken footswitch/one pot) Sola Sound Tone Bender. This is the three knob version built by many people on this board, including myself. There have always been some doubts about the schematic and now was my opportunity to clear this up once and for all!   The schematics posted by RG are pretty close, the only differences are..   1. ALL pots are 100k not 250k and no 2Mg (it appears the Yardbox is a closer clone than thought)   2. The resister from Q2 to earth is 3.3K not 33k   3. The capacitor that parallels the 3.3k resistor is 10uf on my unit not 22uf   4. On my unit there is a 220k resistor between the centre lug of the tone pot and the volume.     The Transistors are all unmarked metal can, no doubt Germanium. The can has a narrow ridge around it about a sixth of the way up.     One more thing, I've always believed that this design is the original design predating the more fuzzface like models with 2 knobs. This one however is dated inside 21 March 1974, so perhaps it is a later design after all or at least was still made that late. The case is a very slightly shallower version of the colorsound box, with silver paint and orange/black text.   Well there it is. I never thought I'd see one of these in the "flesh"     John

 

11/20/1999 4:25 PM
marrk	Thanks for the info, John. Do you have access to a Yardbox to compare the tonal similarities?

 

11/20/1999 8:18 PM

John Catto

quote: "Thanks for the info, John. Do you have access to a Yardbox to compare the tonal similarities?"     Fraid not, only the posting here a while ago which stated that the Yardbox used 100k Pots, a 4.7uf cap on Q2 (mine is 10uf, schematics around say 22uf) and a 250k pot where I said there is a 220k resitor on mine. I forgot to mention this is a seriously backward pedal, not only are the input/output jacks reversed (like a fuzzface etc.) but both the Treble Bass (It's labeling) AND Fuzz controls work backwards! One more thing, it may be the age of some of the components or variables in the transistors but to be honest my clone (made negative ground with AC127's) sounds much better than the real one.

 

11/20/1999 9:01 PM
Aron	>to be honest my clone (made negative ground with AC127's) sounds much better than the real one.     The awful truth is revealed. A lot of those old pedals didn't sound so good.     Aron

 

11/23/1999 4:08 PM

Carsten

Hi John!     I just like the crappy sixties sound,   that's why I build these units. If I   want modern sounds I use my amp ... B)     I still don't understand the bit about   the 250k pot in the Yardbox. You said in   your Solasound there was a 220 K   resistor.   Is this the one from the base   of the first transistor to the negative   supply?   Seems as if a pot there would provide   a kind of bias control of the first   transistor ...     Regards     Carsten

 

11/24/1999 12:10 AM

John Catto

quote: "I still don't understand the bit about   the 250k pot in the Yardbox. You said in   your Solasound there was a 220 K   resistor."     The 220k resistor in the Sola Sound is between the Middle terminal of the tone control and the output volume, nothing exotic. A comparison of the yardbox that was posted here by someone called mark stated that the yardbox had a control labeled gain hooked up in that position...why???

 

11/29/1999 12:39 AM
marrk	The pot acts as a variable resistor allowing you to alter the character of the fuzz. Lower settings are smoother, higher settings are grainier, and more aggressive sounding. It also changes the output level because of its location. Definitely worth putting on a hand wired pedal. Mark

 

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