Sola Sound - Tonebender Mark II Professional  [schematic]

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Re: Tone Bender MkII OC-75

Postby Torchy » 27 Jun 2008, 23:16

http://fuzzcentral.ssguitar.com/mkII.php

The transistor gains for the MKII should be something like 70 for Q1 and Q2 and 100 for Q3.
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Re: Tone Bender MkII OC-75

Postby noelgrassy » 27 Jun 2008, 23:48

Thanks Torchy! That was fast!
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Re: Tone Bender MkII OC-75

Postby bobo » 28 Jun 2008, 00:19

Torchy wrote:http://fuzzcentral.ssguitar.com/mkII.php

The transistor gains for the MKII should be something like 70 for Q1 and Q2 and 100 for Q3.


Thank I already tried Q1, Q2 = 70 and Q3 = 100. The sound is not so good. Someone said Q1& Q2 must have high Hfe than Q3. What's the correct statement.? I tried many hfe of OC-75 but it could not complete with AC-128.
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Re: Tone Bender MkII OC-75

Postby frank.clarke » 28 Jun 2008, 23:09

There is no correct statement, there is no reason to believe the original manufacturer measured gains. Keep trying different transistors until you get the sound you want. Q2 and Q3 should make a usable fuzzface with Q1 removed.
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Re: Tone Bender MkII OC-75

Postby modman » 22 Jul 2008, 01:30

bobo wrote:
Torchy wrote:http://fuzzcentral.ssguitar.com/mkII.php

The transistor gains for the MKII should be something like 70 for Q1 and Q2 and 100 for Q3.


Thank I already tried Q1, Q2 = 70 and Q3 = 100. The sound is not so good. Someone said Q1& Q2 must have high Hfe than Q3. What's the correct statement.? I tried many hfe of OC-75 but it could not complete with AC-128.


I spent days messing with PNP and NPN Tone bender Ge, then built one with random Silicons and just loved it. Absolutely useable pedal, just a fuzz but a good one.

also maybe read this to avoid thinking it's you:
modman wrote:here I think was the original thread on
Relative importance of Gain in a Fuzz Face
for anybody who missed it.


oh yeah, and merged into the older Mark II thread.
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Re: Sola Sound - Tonebender Mark II Professional

Postby The Rotagilla » 10 Oct 2008, 21:48

This thread made for an interesting re-read. Awhile back I had played a Vox two knob ToneBender and was just floored by the sound but not so much that I would have laid out the $1600 they were asking. I hit the same sound by building a Mk.II following the gains suggested by the Fuzz Central layout, but now I'm interested to hear what OC81/lower gain transistors do.
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Re: Sola Sound - Tonebender Mark II Professional

Postby slim_blues_boy » 07 May 2009, 11:15

hi,

could someone help me?
I build TB MKII Pro, and I can't get 4,5-5v on Q3 collector , I use 20k trim.
the lowest I can get is 8,2v.
anybody know what's the problems?

the hfe of all transistor are a little bit lower than should.
I use 2SB178 on Q1 (hfe 60, 150uA leakage), 2SB175 on Q2 (hfe 72, 130uA leakage), and 2SB172 on Q3 (hfe 90, 170uA leakage).
could it be the problem?

thanks
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 07 May 2009, 14:47

what's wrong with 8,2 volts?
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Re: Sola Sound - Tonebender Mark II Professional

Postby slim_blues_boy » 07 May 2009, 17:59

Electric Warrior wrote:what's wrong with 8,2 volts?


well, I read somewhere that it should be around 4.5-5v.
so it's ok with 8.2v?
actually the MKII are works, great sustain, lot of fuzz, a little bit to much fuzz in my taste, lack of definition.
but it's very sensitive, wrong touch on guitar string will produce a little scratch sound.
I tried to get 4.5-5v on the collector and it will need 100K resistor.
the 'scratch' are gone, sustain still good, but it a little bit lack of gain (not powerful as still with 8.2v on the collector), and even more fuzz.

well, I think I will tuned again to find out my 'sweet' spot.

thanks
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 07 May 2009, 19:03

slim_blues_boy wrote:
well, I think I will tuned again to find out my 'sweet' spot.



that's the spirit! :thumbsup

according to David Main Q3 collector voltages varied from 7,6 to 8,9 volts on vintage units, so don't worry. you're in the right ballpark.
http://dam.10.forumer.com/viewtopic.php ... or+voltage
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Re: Sola Sound - Tonebender Mark II Professional

Postby slim_blues_boy » 08 May 2009, 10:03

Electric Warrior wrote:that's the spirit! :thumbsup

according to David Main Q3 collector voltages varied from 7,6 to 8,9 volts on vintage units, so don't worry. you're in the right ballpark.
http://dam.10.forumer.com/viewtopic.php ... or+voltage

thanks for the info, I got 4.5-5v reference from ssguitar.fuzzcentral.com.
well, I also think will try to tuned bias resistor for Q1 and Q2 and see what will happen.
experiment like this is quite interesting for me.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 08 May 2009, 12:03

I did the same thing. It sure was interesting, but I found that I couldn't really improve it. The standard values (OC75 version) worked very well for me.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 09 May 2009, 20:41

here's the layout I'm using

ToneBenderMKIIOC75.png
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Re: Sola Sound - Tonebender Mark II Professional

Postby Scruffie » 09 May 2009, 21:20

Nice, just to double check (it certainly looks like it and i'l assume it's based off it) is that the same layout used in this image http://fuzzcentral.ssguitar.com/mkII.php so if I wanted to use my OC81D's I could just change the few values round, 25uF to 50uF, the diagonal 10k to 100k and the 47k to 100k, have I missed anything?
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Re: Sola Sound - Tonebender Mark II Professional

Postby playon » 09 May 2009, 21:41

The OC81s are likely much lower gain than the OC75
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Re: Sola Sound - Tonebender Mark II Professional

Postby Scruffie » 09 May 2009, 21:47

I thought the original used 81D's ?, I have some OC74's too, Or I have some Black glass 44 & 45's
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Re: Sola Sound - Tonebender Mark II Professional

Postby playon » 09 May 2009, 22:00

I don't know what the original used, but the OC76s are generally higher hfe.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 09 May 2009, 22:08

Nice, just to double check (it certainly looks like it and i'l assume it's based off it) is that the same layout used in this image http://fuzzcentral.ssguitar.com/mkII.php so if I wanted to use my OC81D's I could just change the few values round, 25uF to 50uF, the diagonal 10k to 100k and the 47k to 100k, have I missed anything?


yes, it's based on the original layout.
I don't think you missed anything. I would only worry about the different resistor values. The filter cap was changed to a larger value at some point, but that was independet from the transistor type used. And it shouldn't have any influence on the sound.

I heard the OC81Ds used in Tone Benders were higer gain than the OC75s.... Scruffie, are your OC81Ds vintage Mullards? Have you measured their hfes?

Here's a basic OC81D Tone Bender layout:

ToneBenderMKIIOC81D.png


playon wrote:I don't know what the original used, but the OC76s are generally higher hfe.


There's an OC75 version (came with Impex transistors sometimes - search the D*A*M Forum for more details) and an OC81D version.
David Main posted the hfe values of the OC75s in his Supa Fuzz on the thread I linked to. very high gain. I guess some OC75s were made to different specs than others. Just like OC44s. Some data sheets state that hfe for these is 100, others give a range from 40 to 225.
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Re: Sola Sound - Tonebender Mark II Professional

Postby Scruffie » 09 May 2009, 23:00

I have 4 British Made Mullard OC81D's, they measure around 90-110 on my multi meter, I haven't checked any of these for leakage but they were protected in a copper shield so look brand new and seemed to work in my fuzz factory clone for the 20seconds I tried them, I also have 1 of each Glass OC71, 44 & 45, 2 Metal OC74's (can't remember there hfe probably around 80-100, and one OC75 about 90-110 probably, and 2 Plain OC81s no D all mullard.

I intend to use some carbon comps & paper 'n oil caps I harvested from the radio at the same time as the transistors I listed to build this (I didn't desolder them I snipped the legs so no heat damage & tested as working in my transistor tester I built although it doesn't account for hFe or leakage just says if theyre working and usually works)... recon I'l get away without having to use a trimmer for some of the resistors (btw how do you check caps with a multimeter to make sure there working, i read it somewhere but can't seem to remember if you know off the top of your head)

As for the filter cap, basically the 25uF or 50uF value doesn't really matter, just somewhere in that range then

Cheers for doing the altered layout for me and the replies, greatly appreciated!
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Re: Sola Sound - Tonebender Mark II Professional

Postby Electric Warrior » 09 May 2009, 23:39

Scruffie wrote:I have 4 British Made Mullard OC81D's, they measure around 90-110 on my multi meter, I haven't checked any of these for leakage but they were protected in a copper shield so look brand new and seemed to work in my fuzz factory clone for the 20seconds I tried them, I also have 1 of each Glass OC71, 44 & 45, 2 Metal OC74's (can't remember there hfe probably around 80-100, and one OC75 about 90-110 probably, and 2 Plain OC81s no D all mullard.

I intend to use some carbon comps & paper 'n oil caps I harvested from the radio at the same time as the transistors I listed to build this (I didn't desolder them I snipped the legs so no heat damage & tested as working in my transistor tester I built although it doesn't account for hFe or leakage just says if theyre working and usually works)... recon I'l get away without having to use a trimmer for some of the resistors (btw how do you check caps with a multimeter to make sure there working, i read it somewhere but can't seem to remember if you know off the top of your head)

As for the filter cap, basically the 25uF or 50uF value doesn't really matter, just somewhere in that range then

Cheers for doing the altered layout for me and the replies, greatly appreciated!


had it lying about, I only needed to post it :wink:
no idea how to check caps, sorry.
the caps in vintage units were mostly metallized polyester film iirc, so maybe that would get you closer to vintage specs.
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