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SolaSound - Tonebender 1971

Posted: 17 Jun 2015, 16:02
by Fender3D
This arrived for repairing.

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

Fuzz control works reversed.
Transistors and diode are unsigned.

Enjoy
The attachment SolaSoundTB1sm.JPG is no longer available
SolaSoundTB1sm.JPG
SolaSoundTB2sm.JPG
SolaSoundTB3sm.JPG
SolaSoundTB4sm.JPG
SolaSoundTB5sm.JPG
Schematic
SolaSoundTB6sm.JPG

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 16:57
by sinner
cool bro, thanks for sharing

what's the actual board dimensions?

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 17:18
by Fender3D
76.9 X 75.9 mm

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 17:43
by armdnrdy1
Why couldn't you have received a Colorsound flanger for repair? :slap:

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

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 18:16
by Fender3D
more pics...
P6170005.JPG
P6170006.JPG

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 19:11
by kymar
Thanks for nice pic!
Could you measure voltages Qc1, Qc2, Qc3, please?

Re: SolaSound TB late '60 [pics, schematic]

Posted: 17 Jun 2015, 20:04
by sinner
kymar wrote:Thanks for nice pic!
Could you measure voltages Qc1, Qc2, Qc3, please?
this!

Re: SolaSound - Tonebender (late 60s)

Posted: 17 Jun 2015, 22:16
by Electric Warrior
Can you read the pot codes? Probably early '72.

Re: SolaSound TB late '60 [pics, schematic]

Posted: 18 Jun 2015, 10:27
by Fender3D
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

Re: SolaSound - Tonebender (late 60s)

Posted: 18 Jun 2015, 10:29
by Fender3D
I forgot

Battery = 9.70V

Re: SolaSound - Tonebender (late 60s)

Posted: 18 Jun 2015, 10:35
by Fender3D
Updated schematic:
added transistors voltages, moved battery switch to output jack
Sola Sound Tone Bender.pdf

Re: SolaSound TB late '60 [pics, schematic]

Posted: 18 Jun 2015, 11:46
by Electric Warrior
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.

Re: SolaSound - Tonebender 1971  [schematic]

Posted: 18 Jun 2015, 15:40
by Fender3D
lol

1.2 corrected electros polarity
Sola Sound Tone Bender.pdf
(37.89 KiB) Downloaded 296 times

Re: SolaSound - Tonebender 1971

Posted: 19 Jun 2015, 15:45
by jalmonsalmon
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!

Re: SolaSound - Tonebender 1971

Posted: 19 Jun 2015, 20:36
by Electric Warrior
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..

Re: SolaSound - Tonebender 1971

Posted: 25 Jun 2015, 15:07
by Bret608
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?

Re: SolaSound - Tonebender 1971

Posted: 25 Jun 2015, 15:22
by Electric Warrior
I've seen a couple of marked ones in Tone Benders, but never the same type twice. :mrgreen:

Re: SolaSound - Tonebender 1971

Posted: 25 Jun 2015, 15:58
by Bret608
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!

Re: SolaSound - Tonebender 1971

Posted: 25 Jun 2015, 21:45
by Electric Warrior
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!

Re: SolaSound - Tonebender 1971

Posted: 26 Jun 2015, 09:06
by sinner
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