SolaSound - Tonebender 1971

Fender3D · Post by **Fender3D** » 17 Jun 2015, 16:02

This arrived for repairing.

It's a late '60 Tone Bender by Sola Sound.
I redraw the schematic with actual values and wires color...

Fuzz control works reversed.
Transistors and diode are unsigned.

Enjoy

The attachment SolaSoundTB1sm.JPG is no longer available

Schematic

sinner · Post by **sinner** » 17 Jun 2015, 16:57

cool bro, thanks for sharing

what's the actual board dimensions?

Fender3D · Post by **Fender3D** » 17 Jun 2015, 17:18

76.9 X 75.9 mm

armdnrdy1 · Post by **armdnrdy1** » 17 Jun 2015, 17:43

Why couldn't you have received a Colorsound flanger for repair?

I'm working on the board routing and....I could use a few trace side shots!

Fender3D · Post by **Fender3D** » 17 Jun 2015, 18:16

more pics...

kymar · Post by **kymar** » 17 Jun 2015, 19:11

Thanks for nice pic!
Could you measure voltages Qc1, Qc2, Qc3, please?

sinner · Post by **sinner** » 17 Jun 2015, 20:04

kymar wrote:Thanks for nice pic!
Could you measure voltages Qc1, Qc2, Qc3, please?

this!

Electric Warrior · Post by **Electric Warrior** » 17 Jun 2015, 22:16

Can you read the pot codes? Probably early '72.

Fender3D · Post by **Fender3D** » 18 Jun 2015, 10:27

kymar wrote:Thanks for nice pic!
Could you measure voltages Qc1, Qc2, Qc3, please?

Q1:

C = -5.024 V
B = -1.300 V
E = -1.232 V

Q2:

C = -5.024 V
B = -1.232 V
E = -1.140 V

Q3:

C = -2.540 V
B = -0.071 V
E = 0 V

Electric Warrior wrote:Can you read the pot codes? Probably early '72.

On pot you find:

Radiohm 100K A D-74

Fender3D · Post by **Fender3D** » 18 Jun 2015, 10:29

I forgot

Battery = 9.70V

Fender3D · Post by **Fender3D** » 18 Jun 2015, 10:35

Updated schematic:
added transistors voltages, moved battery switch to output jack

Sola Sound Tone Bender.pdf

Electric Warrior · Post by **Electric Warrior** » 18 Jun 2015, 11:46

Fender3D wrote:
On pot you find:

Radiohm 100K A D-74

Thank you! That would be D-71. By 1974 the pot codes were stamped into the top surface of the pots.

Fender3D · Post by **Fender3D** » 18 Jun 2015, 15:40

lol

1.2 corrected electros polarity

Sola Sound Tone Bender.pdf: (37.89 KiB) Downloaded 296 times

jalmonsalmon · Post by **jalmonsalmon** » 19 Jun 2015, 15:45

32uF is a funky value but I assume since it is just going from -VCC to ground, a 33uF will be okay or whatever works LOL

thanks!

Electric Warrior · Post by **Electric Warrior** » 19 Jun 2015, 20:36

Sure. Sola Sound mostly used 22µF or 25µF as a power filter cap for these in that particular era. They started out with 50µF, but whatever works..

Bret608 · Post by **Bret608** » 25 Jun 2015, 15:07

Cool unit! Glad you were able to share the voltages. Q3 was definitely what I would have expected. Q1 and Q2 are slightly higher than I thought they would be on the collector. Then again it's still roughly half supply voltage.

I know these "top hat"-style transistors are normally not marked. Has anyone ever seen marked versions of them anywhere?

Electric Warrior · Post by **Electric Warrior** » 25 Jun 2015, 15:22

I've seen a couple of marked ones in Tone Benders, but never the same type twice.

Bret608 · Post by **Bret608** » 25 Jun 2015, 15:58

That's what I love about this circuit, nice and forgiving of different transistor types.

EW, I'm actually working on a build right now using your MkIII layout. The one with the 680k/150k bias string...I think I've got just the right gains/leakages in my stash of no-name germaniums. We'll see I guess!

Electric Warrior · Post by **Electric Warrior** » 25 Jun 2015, 21:45

Good luck! Trying different types in this circuit sure pays off! Q3 is quite sensitive to leakage. Great for shaping the tone. And I found that transistors wired up as a diode sound different from the germanium diodes I have. Worth a try!

sinner · Post by **sinner** » 26 Jun 2015, 09:06

I don't think leakage is that bad in mk3. I kind of like it if it leaks. I often fake leakage setting resistor or resistor in series with pot between C and B

SolaSound - Tonebender 1971 [schematic]