Silicon Tone Bender

mictester · Post by **mictester** » 10 Nov 2009, 18:21

gus wrote:Your input resistance might not be as high as you think it is and how stable is the input bias (base current vs bias current vs temp).
You have a cap bypassed emitter resistor. hfe x emitter leg resistance in || with both of the bias resistors.

What Colorsound has a 100 ohm emitter resistor with a 10K collector and a 5K bias pot and 47K feedback/bias resistor?

None of them!. The 5k preset was added to get rid of the nasty gating effect on the original pedal and to give some range to the "fuzz" (abuse) control. The other component changes just made it sound better. Ex-factory, the thing was truly horrible, and was almost unusable.

The later component changes were to give higher gain. The first stage bias is perfectly good enough - another version has current biasing with 1M5 from base to collector and no base to ground resistor, and this is almost as good, though noisier.

If you don't like it, don't build it!!. The dozen or so that I've built to this recipe are in constant use by working musicians, and the only complaint I've had is radio interference in one of them that was cured with a small value capacitor between base and collector of the first transistor.

Post by **azrael** » 12 Nov 2009, 15:13

I think gus is just pointing out that it's similar to his Tonebender Design, which DougH modified into the Hot Silicon.

BTW, gus, in case ya come back to this thread...Are the transistor gains for the Hot Silicon specific? I just stuck some that I had lying around in there.

gus · Post by **gus** » 12 Nov 2009, 18:03

https://www.diystompboxes.com/pedals/3tran.JPG
https://www.diystompboxes.com/pedals/gusFuzzFace.gif
https://www.diystompboxes.com/pedals/rocket.JPG

Look at the distortion sections. As far as I know(I would be interested to know if someone knows of a fuzz built like this before 1998) no one used a 100 emitter resistor and 10K collector on the first transistor to control the open loop gain in the FF type gain stage for a FUZZ EFFECT before this was posted. IIRC Jack's circuit came after this and used a 33K.
http://www.muzique.com/lab/yaff.htm

I you look close the 2 transistor fragment I like as a fuzz is not far away from a Vox circuit. I added the emitter resistor and passive lowpass(this was before the axis face http://fuzzcentral.ssguitar.com/axisface.php) and made the bias adjustable for different tones with the 5K bias pot.

I have older transistor books the FF type circuit is old and the use of an emitter resistor and the math is in at least one book I own from the 60's and maybe before. The use of the 100 emitter resistor is no big deal: However I did not see it used before in FF type circuits for a fuzz. I would be interested to know if someone knows of a fuzz built like this before 1998.

You did not see any of the above schematics before you made your design?

azrael I like hfe 200 and above, try different ones.

mictester · Post by **mictester** » 13 Nov 2009, 08:18

gus wrote:
You did not see any of the above schematics before you made your design?

.

Frankly, no. The Colorsound pedal I modified was dated 1978, and had a "Macari's" price sticker underneath for £34.95. I was given the thing to see if I could make it sound better, because it was horribly gated and "splattery", and had a wince-inducing top end. The input stage is "as was" - it was the only part of the circuit that worked properly. I only modified the thing because its owner liked the box it came in, and I was pleasantly surprised by how good it sounded when I'd finished.

This lead to my interest in the Benders - I owned a few of them in the days when I gigged regularly, but never really liked them back then. I built about a dozen of them with varying components. The three germanium-based ones were disappointing, so I recovered the transistors and used them elsewhere. Most of the silicon ones sounded horrible, but there were two that sounded great!

I did the PCB layout so that I could quickly make a few more of the version that worked best.

mictester · Post by **mictester** » 13 Nov 2009, 21:36

mictester wrote:
I did the PCB layout so that I could quickly make a few more of the version that worked best.

As promised - here's the PnP

: Bender-PnP.gif (4.43 KiB) Viewed 3253 times

telecaster · Post by **telecaster** » 13 Nov 2009, 22:27

Great sounding project, Thanks.

SPeter · Post by **SPeter** » 14 Nov 2009, 03:17

Thanks for the PnP mictester?

mictester · Post by **mictester** » 26 Nov 2009, 23:38

mictester wrote:
Most of the silicon ones sounded horrible, but there were two that sounded great!

This is the second version that sounded really great. More modifications! I've just unearthed the board from a pile of real money-earning stuff, and had a further play...

This is a Tonebender for the maniacs amongst us, for the hairy-toothed, glassy-eyed, bleeding-eared noise merchants!! Despite all its howling qualities, you can still clean it up a lot with the guitar volume! I actually can't play through this thing, but my thrash-metalling nephew LOVES it!

Mind your ears, and enjoy!

mictester · Post by **mictester** » 09 Dec 2009, 21:15

gus wrote:Wow. You don't give credit to where the circuit came from? That distortion section looks to be the one that has been posted at Aron's for years.

I've just looked at this thread again. Just to point out to "Gus" and all the rest of the boutique boobs - I only ever saw "Aron's" recently (pointed there by a posting from Dirk as I recall). The "Hot Silicon" never crossed my path until I looked it up after Gus' snippy comments. The "Hot Silicon" looks like a poor copy of a Macari's / Colorsound circuit from the late 70's, so is not in the slightest bit original.

The SiliBender came from fixing the crappy Macari's box that a friend had for years (and never used because it sounded terrible), changing some values in it, then adding the preset in series with the Fuzz pot. My friend was amazed - especially when I told him that the price for the modification was just two beers!

After the first one, I became a bit of a Tonebender addict, and now I've built several dozen of them. I don't like the germanium ones much - they're too component-dependent, and temperature sensitive, and don't have much output. The silicon ones are great - they are the fuzz I wish I'd had as a kid!

sunburnedgoat · Post by **sunburnedgoat** » 13 Dec 2009, 00:21

Hi, new guy here. Total electronics newb. I put this on my breadboard last night, and gotta say - kudos! I'm really loving the way this sounds. Can get a very gated fuzz, or a more smooth, modern distortion. I will probably make the trim an external control, as I like being able to dial in that "crunch". I'm a bit naive about the other side of the conversation, but that matters little to me anyway. The version I threw together is with the fat switch, and will probably put the high gain version together tomorrow and see how that suits me.

Anyway, just thought I'd say thanks!

Also... curious about possibly getting a bit more from the output. Got the volume dimed right now and it's definitely loud enough, but I just want to get unity much much earlier, with the available torque to destroy worlds, if desired

RnFR · Post by **RnFR** » 13 Dec 2009, 02:24

try a linear pot instead of log. it'll get louder earlier in the sweep.

mictester · Post by **mictester** » 13 Dec 2009, 21:42

RnFR wrote:try a linear pot instead of log. it'll get louder earlier in the sweep.

Correct, but the actual maximum output level won't change! You could increase the value of the 10k from the base of the third transistor to the rail - lift one end and put a 4k7 in series. You'd have to readjust the preset, but it would give some more output.

I find that the thing is perfectly "loud" enough - I get more level with a simple booster / tone control unit after it if I need, though it's plenty loud enough for the inputs of my AC30, Sessionmaster or anything else I've tried it with!

sunburnedgoat · Post by **sunburnedgoat** » 15 Dec 2009, 00:42

Absolutely, you are right that it's plenty loud enough as is. I was just asking out of devilish need to take it over the top. The 4k7 did the trick perfectly! Thank you! It sounds very classic through my Rock Block 1 watter. And gets massively doomy through a Model T half stack - which is what I was looking for. Going to try the high gain version tonight. Thanks for the help guys. Now if I can just get my head around the theory of these things, I can start inventing my own circuits to share in kind

mictester · Post by **mictester** » 15 Dec 2009, 17:03

sunburnedgoat wrote:Absolutely, you are right that it's plenty loud enough as is. I was just asking out of devilish need to take it over the top. The 4k7 did the trick perfectly! Thank you! It sounds very classic through my Rock Block 1 watter. And gets massively doomy through a Model T half stack - which is what I was looking for. Going to try the high gain version tonight. Thanks for the help guys. Now if I can just get my head around the theory of these things, I can start inventing my own circuits to share in kind

You're very welcome. If you discover any useful mods, please add them to this thread. I'm never too proud to learn from anyone who wants to contribute!

Post by **Brink** » 20 Dec 2009, 22:18

mictester wrote:
mictester wrote:This is the second version that sounded really great. More modifications! I've just unearthed the board from a pile of real money-earning stuff, and had a further play...

Why two 10n capacitors in series - that's equivalent to a 5n cap, right?

mictester · Post by **mictester** » 21 Dec 2009, 00:35

Brink wrote:
mictester wrote:
mictester wrote:This is the second version that sounded really great. More modifications! I've just unearthed the board from a pile of real money-earning stuff, and had a further play...
Why two 10n capacitors in series - that's equivalent to a 5n cap, right?

Exactly right! It was convenient for two reasons - I didn't have any 4n7 caps at the time, and it allowed better routing on the PCB.

It doesn't hurt to play around with the capacitor values in the tone control part of the circuit - there are many changes that might just give the range of sounds you're looking for!

Post by **Brink** » 26 Dec 2009, 06:25

I redrew the schematic.

mictester · Post by **mictester** » 28 Dec 2009, 02:22

Brink wrote:I redrew the schematic

Thanks. Good re-draw.

I've done a bit more experimenting, and have found a few further modifications that can give an even greater range of sounds.

This is basically such a simple circuit, that changing anything will have some effect! Please experiment!

devastator · Post by **devastator** » 02 Jan 2010, 16:07

I made that circuit on breadboard today but I've some doubts about the tone control , what's its role ? that's a big muff tone control but without the midscoop right ? 'cause I'm not really happy with it.

I tried to put the tonestack of the Voodoo lab superfuzz (a variable midscoop + a kind of bass resonnance) but , that was the same, not really convainced by that too. (Plus I may did some wrong because the resonnance acted like a gain control, adding a monster gain to the circuit) .

Any ideas for a similar kind of control ?

Otherwise, the fuzz circuit sounds cool , gainless than a fuzz face .

mictester · Post by **mictester** » 02 Jan 2010, 20:46

devastator wrote:I made that circuit on breadboard today but I've some doubts about the tone control , what's its role ? that's a big muff tone control but without the midscoop right ? 'cause I'm not really happy with it.
.

Yep - it's pretty much the basic BMP tone control. Reduce the 8n2 capacitor (I use 4n7) to give more range to the tone control, or consult the online tonestack calculators to redesign it to suit your style. The components as shown are the ones that I found sounded "right" to my ears!

Incidentally, check your wiring carefully - it's got much more gain than a fuzz-face!

BTW - this circuit (built into small Eddystone diecast boxes, with internal circuitry sealed into waterproof (beer-proof) resin, and with NiMH rechargeable batteries) is currently in use by two big name guitarists (both London based, and both going back as far as the 1960s). Both players like the range of retro fuzzy sounds available, and both have commented on how these sound "like the better Macari's boxes from years ago".