Sola Sound - Tone Bender Mark I (1965)  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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vanessa
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Post by vanessa »

I posted this a long time ago, not a lot of interest. To me it was a holy grail find. You can use the Zonk Machine PCB that's floating around with a little rework. Enjoy!

-Van

BTW: 9VDC

Image
Last edited by vanessa on 20 Aug 2007, 19:35, edited 2 times in total.

call1800ksmyazz
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Post by call1800ksmyazz »

Very cool Vanessa. Thanks! :D

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RLBJR65
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Post by RLBJR65 »

Nice! Must have missed it the first time around.

Thanks!

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Post by MoreCowbell »

Gracias !

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Post by markm »

Thanks Vanessa!
Ummmm.
What's up with the avatar?
Now you're Marie Antonette (sp?!!)?
Wasn't the mona lisa there a moment ago? :?
Join together with the "Banned"!

vanessa
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Post by vanessa »

markm wrote: Wasn't the mona lisa there a moment ago? :?
Elizabeth the 1st. I could not shrink down the Mona Lisa to avatar size and make it look good. Funny the original [Mona Lisa] was avatar size out of the gate.

:lol:

MoreCowbell
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Post by MoreCowbell »

I whipped up this PCB for the TB MKI.

It could be made smaller, but I wanted to leave extra room for easy component installation.

PCB LAYOUT IS HERE

PNP IS HERE

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Post by JHS »

The 2C382 are very hard to get, if you subs it with other Ge-trannies all values for emitter- and collector-Rs must be recalculated...

I reccomend to use trimpot, but you need the voltages of the original TB1 to adjust the trimpots to the correct values.

JHS

vanessa
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Post by vanessa »

From an old post:

Q1 hfe = ?
Q2 hfe = 120
Q3 hfe = 92

I would guess based on others findings of the FZ-1 that Q1 is 50-70 hfe.

I'll add that this thing sounds great with those crap transistors you could never get yourself to throw away. It loves leakage, not off the charts but some leakage for all the Q's and a low value for Q1 really makes this one work.

kagaxdx
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Post by kagaxdx »

IMO it's an interesting circuit in some aspects...
That output, is using 2M2 :shock: in series with a 500K :shock: vol pot... :? But then lowering impedance before this there's a 47K to gnd.
I'd like to know why?
I know it could be achieved similar results with like a 47K in series with a 10K vol pot (instead of the values above) and pretty much similar impedance...? :?

I bet it may have an influence to the tone... a 2M2 resistor IN SERIES with a 500K vol pot... :roll:

Someone could try to make me (us) see what's the meaning of this?
Thanks in advance...

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Post by bajaman »

Hello Kagaxdx
The 2M2 resistor would roll off a lot of the high frequency buzz or scratchyness in this circuit.
Cheers
bajaman

ps: a well known high end HiFi stereo amplifier manufacturer used to connect a 75K ohm resistor in series with the CD input socket (one each channel of course) in his top end hybrid Stereo Amplifier. guess what - all the reviewers remarked on it's smooth sounding, less stident, less edgy top end response (more like a vinyl record) - (all the other inputs had NO series resistance).
:wink: :lol:
bajaman

kagaxdx
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Post by kagaxdx »

bajaman wrote:Hello Kagaxdx
The 2M2 resistor would roll off a lot of the high frequency buzz or scratchyness in this circuit.
Cheers
bajaman

ps: a well known high end HiFi stereo amplifier manufacturer used to connect a 75K ohm resistor in series with the CD input socket (one each channel of course) in his top end hybrid Stereo Amplifier. guess what - all the reviewers remarked on it's smooth sounding, less stident, less edgy top end response (more like a vinyl record) - (all the other inputs had NO series resistance).
:wink: :lol:
bajaman
Thank you Baja,
Then..... 8) If you take a Fuzz Face a silicon one, you have usually more gain (hfe) and more frequency bandwidth (more treble/piercing highs), we could search for a low HFE silicon transistor (or piggback) and for the different high end response use this sort of "soothness"? :wink:

Take the output straight from Q2 colector and conect to a 470K resistor in series with a 100K vol pot... :idea:

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Post by MoreCowbell »

kagaxdx wrote:
bajaman wrote:Hello Kagaxdx
The 2M2 resistor would roll off a lot of the high frequency buzz or scratchyness in this circuit.
Cheers
bajaman

ps: a well known high end HiFi stereo amplifier manufacturer used to connect a 75K ohm resistor in series with the CD input socket (one each channel of course) in his top end hybrid Stereo Amplifier. guess what - all the reviewers remarked on it's smooth sounding, less stident, less edgy top end response (more like a vinyl record) - (all the other inputs had NO series resistance).
:wink: :lol:
bajaman
Thank you Baja,
Then..... 8) If you take a Fuzz Face a silicon one, you have usually more gain (hfe) and more frequency bandwidth (more treble/piercing highs), we could search for a low HFE silicon transistor (or piggback) and for the different high end response use this sort of "soothness"? :wink:

Take the output straight from Q2 colector and conect to a 470K resistor in series with a 100K vol pot... :idea:
Ive done some similar experiments, and had mixed results. To be honest, the old "cap to ground" seemed to work better for me, as it retained more of the dynamic properties of the circuit.

kagaxdx
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Post by kagaxdx »

Thank you Morecowbell, thats good to hear from someone that had previosly tried that.
That's the good thing: We always keep on searching ways to improve tone 8)

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Post by MoreCowbell »

kagaxdx wrote:Thank you Morecowbell, thats good to hear from someone that had previosly tried that.
That's the good thing: We always keep on searching ways to improve tone 8)
No problem.

Honestly, if I were building a MKI, I'd probably eliminate the 2M2 resistor and use a cap to ground, somewhere between 470pF and .001uF.

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alnico
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Post by alnico »

There is a resistor missing on the schematic. It should have a 33K from the wiper of the Attack pot to ground.

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Post by vanessa »

alnico wrote:There is a resistor missing on the schematic. It should have a 33K from the wiper of the Attack pot to ground.
Do you have one? How do you know?



:lol:

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Post by analogguru »

There is a resistor missing on the schematic. It should have a 33K from the wiper of the Attack pot to ground.
This maybe true for the Maestro Fuzztone. If it would be true for the Mk I, then somebody must have stolen it from this unit:

http://82.110.105.12/stompboxes.co.uk/i ... oooiol.JPG

but what I can see is, that in realitiy R3 is not 470k - it is 180k, especially when I look at it from a different angle - like this:

Image

analogguru
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Post by vanessa »

analogguru wrote: but what I can see is, that in realitiy R3 is not 470k - it is 180k, especially when I look at it from a different angle - like this:

Image

analogguru
Good catch AG.
analogguru wrote: This maybe true for the Maestro Fuzztone. If it would be true for the Mk I, then somebody must have stolen it from this unit:
What do you mean AG?
Last edited by vanessa on 22 Aug 2007, 19:18, edited 1 time in total.

analogguru
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Post by analogguru »

Good catch AG
As I said:
I only believe what I see with my own eyes :wink:

There is a resistor missing on the schematic. It should have a 33K from the wiper of the Attack pot to ground.
This maybe true for the Maestro Fuzztone. If it would be true for the Mk I, then somebody must have stolen it from this unit:

http://82.110.105.12/stompboxes.co.uk/i ... oooiol.JPG
What do you mean AG?
I mean, that the picture shows the original innards of a MkI and that I cannot see a resistor in parallel to the poti there.

If you look at the near identical Maestro Fuzztone schematic (or guts) you will find this resistor. The MkI should be a clone of the fuzztone but wasn´t sold very often, maybe due to the patent of the Fuzztone.

IMHO for this reason the Fuzz Face circuit was used instead to avoid patent lawsuits. Nobody cared this time about silizium/germanium and whatever. The only important thing was that it should distort/produce a squarewave in any way.

The circuit was the "european/british answer" to the patent of the Fuzztone. A funny question is only, what came first: the TB Mk 1,5 or the Fuzz Face ?

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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