Sola Sound - Tonebender Mark II Professional  [schematic]

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

Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 27 Jul 2013, 23:48

I'm pretty sure those DAM units are biased at Q3, phibes. He mentions putting the probe on one of the legs of the 8k2 resistor, and that resistors' use is for the biasing of the collector of Q3. I went back to my guitar fx layout, and the 8k2 resistor is connected to the collector of Q3. I removed the 8k2 resistor and placed a linear 2k pot in its' place, as shown as the 'bite' knob on the top of the unit. So, to answer your query, I'm biasing Q3. I think it sounds close.
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Re: Sola Sound - Tonebender Mark II Professional

Postby phibes » 28 Jul 2013, 06:40

Yeah the bias point is at Q3 but the trimmer setting the bias is on Q2's collector (leaving the 8k2 alone and subbing the 47k on Q2's collector for a 100k trimmer). Your box sounds really good, twas just suggesting some further tweaking since you checking the DAM technique.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 28 Jul 2013, 23:40

Ratfarts!

Now you got me thinking into trying that out too, phibes.

Maybe tweaking the collector on Q2 is the better way of biasing, I'll make another one and breadboard it, to experiment. But, for now I'm just happy that this project turned out as well as it did.

Thanks for the heads up, phibes!
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Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 30 Jul 2013, 06:07

I couldn't resist, so, I tore my unit apart again and subbed a 100k pot on the collector of Q2. But, was unable to dial in 7.5v, I tried a
value of 100k then 220k and so forth in series to try to get 7.5v on the 8k2 resistor, and when I did it didn't sound any different as before. l found the unit sounded squishy, farty, when I returned the 8k2 resistor, all the pot did on Q2 was to control the splattiness, gating of the effect. So, I put things back the way they were, pot on Q3, 100k resistor back to Q2. I gave the pot on Q2 a try, but, it didn't make much of difference, phibes.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 30 Jul 2013, 14:01

That's the whole point of the bias control there: dialing in just the right amount of gating and clean up. But you don't need a trim for that. You could just swap transistors until you find a set that works just right.
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Re: Sola Sound - Tonebender Mark II Professional

Postby phibes » 30 Jul 2013, 15:44

Bummer, making that switch uses gives a little more control on the voltage. The low to none leakage on the Russian transistor might be playing with that though. You're probably best going with what ya got now. It's always fun to fuck with all the methods though!
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Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 30 Jul 2013, 22:22

Thanks for the replies, guys.

Funny that mention that russian transistor in Q2, phibes, when I was auditioning the transistors I tried one in Q1 and it sounded like a overdrive.

I believe the transistors I have chosen have enough gating, electric warrior, I guess I was expecting something else with the pot on Q2.

I guess the old saying stands firm here, 'If it ain't broken, don't fix it'.
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Re: Sola Sound - Tonebender Mark II Professional

Postby shiflet » 03 Aug 2013, 20:09

There is a pcb that is PNP with negative ground?
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Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 03 Aug 2013, 23:33

I pm'd you the link that my box was made from. :D
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Re: Sola Sound - Tonebender Mark II Professional

Postby dthurstan » 17 Aug 2013, 12:30

Hey

Heres my version of the Mk II I made a while back;

Image

Image

It's got a charge pump for the -9V. I've used AC128s and here are the voltages;

V=-8.98, 100K on Q1 base. 100K trim (~47k) on Q2 collector
C B E
Q1 -7.41 -0.63 0 hfe ~59 leakage 141mA
Q2 -0.3 -0.8 0 hfe ~51 leakage 118mA
Q3 -8.75 -0.3 -0.2 hfe ~82 leakage 163mA

Q2 had an accident a couple of weeks ago when I snapped a leg! But I managed to solder it back on with no increase in hfe or leakage.

Image

Here is a clip of it in action. First clean, then with the transistors above and then with Q1 the same, Q2 is now the 82 hfe trans and Q3 98 hfe with leakage of 422mA.

https://dl.dropboxusercontent.com/u/76332771/Mk%20II/Mk%20II.mp3

I didn't readjust the trim so Q3c was about -7.6 with 98 gain transistor, it sounds a touch more compressed to me. Signal path is a Jazzmaster bridge pup - Mk II - Fender Deluxe 112plus - Behringer C2 - Tascam US-122L. Let me know what you think.
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Re: Sola Sound - Tonebender Mark II Professional

Postby bato001 » 17 Aug 2013, 14:05

dthurstan wrote:Hey

Heres my version of the Mk II I made a while back;



It's got a charge pump for the -9V. I've used AC128s and here are the voltages;

V=-8.98, 100K on Q1 base. 100K trim (~47k) on Q2 collector
C B E
Q1 -7.41 -0.63 0 hfe ~59 leakage 141mA
Q2 -0.3 -0.8 0 hfe ~51 leakage 118mA
Q3 -8.75 -0.3 -0.2 hfe ~82 leakage 163mA

Q2 had an accident a couple of weeks ago when I snapped a leg! But I managed to solder it back on with no increase in hfe or leakage.

[ Image ]

Here is a clip of it in action. First clean, then with the transistors above and then with Q1 the same, Q2 is now the 82 hfe trans and Q3 98 hfe with leakage of 422mA.

https://dl.dropboxusercontent.com/u/76332771/Mk%20II/Mk%20II.mp3

I didn't readjust the trim so Q3c was about -7.6 with 98 gain transistor, it sounds a touch more compressed to me. Signal path is a Jazzmaster bridge pup - Mk II - Fender Deluxe 112plus - Behringer C2 - Tascam US-122L. Let me know what you think.



That is a sweet sounding MKII. Excellent work!!!! :thumbsup
"Ever wondered how some of your favourite guitar players got their tone? Me too. Probably a good amp and lots of practice." Little Lord Electronics Homepage

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Re: Sola Sound - Tonebender Mark II Professional

Postby jalmonsalmon » 27 Aug 2013, 16:20

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Re: Sola Sound - Tonebender Mark II Professional

Postby sinner » 27 Aug 2013, 16:35



Holly molly, my wife is cheaper!

More than $15/piece? They're going pricey...
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Re: Sola Sound - Tonebender Mark II Professional

Postby jalmonsalmon » 27 Aug 2013, 18:09

Dude is nuts... top dollar for a bulk order LOL
I can see those costing say... $2500 for all those, if they are all good and no duds :blackeye
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 27 Aug 2013, 19:11

sinner wrote:


Holly molly, my wife is cheaper!

More than $15/piece? They're going pricey...


I wouldn't say that. It's just an offer at a fantasy price.
$4/piece would be realistic.
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Re: Sola Sound - Tonebender Mark II Professional

Postby stomper » 05 Sep 2013, 01:29

I found this video of Gary Hurst studying the Marshall SupaFuzz prototype. This fellow who posted it has several other videos too. Fabulous historical and technical information. Be ready to be knocked out by this collection of gear.
http://m.youtube.com/watch?feature=relmfu&v=3RtKIaUzUXU
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Re: Sola Sound - Tonebender Mark II Professional

Postby Nacho5 » 05 Sep 2013, 18:29

Hi guys! I'm from Argentina. I build GGG proyect Sola Sound 3 knobs NPN Silicon, this:

http://www.generalguitargadgets.com/pdf ... 3si_sc.pdf


I have only one question.

Transistors hfe??


sorry for me english
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Re: Sola Sound - Tonebender Mark II Professional

Postby cdeschenes » 05 Sep 2013, 19:50

Nacho5 wrote:Hi guys! I'm from Argentina. I build GGG proyect Sola Sound 3 knobs NPN Silicon, this:

http://www.generalguitargadgets.com/pdf ... 3si_sc.pdf


I have only one question.

Transistors hfe??


sorry for me english


This might be relevanthttp://www.diystompboxes.com/smfforum/index.php?topic=71849.0
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Re: Sola Sound - Tonebender Mark II Professional

Postby soggybag » 07 Sep 2013, 01:50

Fred_Garvin wrote:Here's my version of the Tonebender MK II

I used the biggest goofiest case I could find on Ebay. There's no mojo parts, even the transistors are average pnp germanium.
Transistors used are TUNGSRAM ac128 (66hfe, leak: .160mA) Q1, Russian 1t308B (79hfe , leak: .000mA) Q2, and lastly a NTE158 (120hfe, leak: .230mA) Q3. All measurements done by the Peak atlas DCA55.
No pots on Q2 or Q3, I just used my ears to select the best candidates.

I used the vero board layout found at Guitar Fx Layouts for this build, and it uses the ICL7660S to invert the voltage back to standard negative ground.

Why the big box? It was needed to contain all that tone. Yes, it does sound that huge. Sound clips to follow, soon.
But, it's silver? The Silver Dragon doesn't sound as cool as the Black Dragon, really, now does it?

[ Image ]

[ Image ]

[ Image ]

[ Image ]

[ Image ]


I like that case where did you get it? Is it strong enough to step on? I bought some slope front cases like this from Mouser. The metal too light, you could easily bend it by stepping on it.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Fred_Garvin » 16 Sep 2013, 06:23

http://pages.ebay.com/link/?nav=item.vi ... 1056448565

I had to reinforce the case. It can withstand the weight of a good heavy foot.

It wasn't made for the use given. But, after some modification, it's all fine.
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