Silicon Tone Bender

devastator · Post by **devastator** » 02 Jan 2010, 22:54

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

Hi, I think so, I'll check that tomorrow. But the "tone" isn't the same , compared to a fuzz face , this is bassless and maybe give that impression to have less gain.

I keep testing different tone controls . If I don't find what I want I'll go back to the original tonestack, a big muff style (I'm not really fan of that with its midscoop but with a switch (and I did that on a big muff I modded ) that can be a great addition).

mictester · Post by **mictester** » 03 Jan 2010, 15:30

devastator wrote:
Incidentally, check your wiring carefully - it's got much more gain than a fuzz-face!
Hi, I think so, I'll check that tomorrow. But the "tone" isn't the same , compared to a fuzz face , this is bassless and maybe give that impression to have less gain.

I keep testing different tone controls . If I don't find what I want I'll go back to the original tonestack, a big muff style (I'm not really fan of that with its midscoop but with a switch (and I did that on a big muff I modded ) that can be a great addition).

If you want more "bottom end", increase the input capacitor or the 100n capacitor after the first transistor!

devastator · Post by **devastator** » 03 Jan 2010, 16:22

Yeap but increasing that cap will add more distortion , right ?

Actually , the circuit by itself sounds good, I'm just looking for a cool tone circuit with , at least, two knobs to put the circuit .

Also, the fuzz knob isn't as I like, (that's the same case with all fuzz face type circuit I build by the way) . I'll change for a fixed resistor and put a kind of big muff gain control, a voltage divider after the first transistor.

mictester · Post by **mictester** » 03 Jan 2010, 17:24

devastator wrote:Yeap but increasing that cap will add more distortion , right ?

Actually , the circuit by itself sounds good, I'm just looking for a cool tone circuit with , at least, two knobs to put the circuit .

Also, the fuzz knob isn't as I like, (that's the same case with all fuzz face type circuit I build by the way) . I'll change for a fixed resistor and put a kind of big muff gain control, a voltage divider after the first transistor.

Yes the cap increase will give more distortion, but you could tame that with your proposed drive control pot after the first stage. My brother has just built a device based on this design, but replaced the tone control circuit and the final transistor with an op-amp based Baxandall tone control. Give it a try!

devastator · Post by **devastator** » 03 Jan 2010, 17:42

Yep I'd try that, simple and easy to try.

a baxendall like the one there is in orange amp or something more complexe using gyrator and cut/boost pot (dod did that in their distortion pedals) ?

mictester · Post by **mictester** » 03 Jan 2010, 19:12

devastator wrote:Yep I'd try that, simple and easy to try.

a baxendall like the one there is in orange amp or something more complexe using gyrator and cut/boost pot (dod did that in their distortion pedals) ?

The simplest possible Baxendall - the Orange one has roughly the right values to voice the control for guitar, so it's a good choice.

Post by **azrael** » 13 Feb 2010, 17:43

What kind of gains should we use for the BC109s? Have you tried other transistors like 2N2222, 2N3440, 2N3904?

mictester · Post by **mictester** » 13 Feb 2010, 20:39

azrael wrote:What kind of gains should we use for the BC109s? Have you tried other transistors like 2N2222, 2N3440, 2N3904?

I've built them with all sorts of transistors. I built two last week that used BC550 transistors throughout. The BC109C that I originally used has a fairly high Hfe and low noise, so it's a good choice. My brother built one using 2N2369A transistors, which are really low gain RF devices. The character of the pedal changed completely (I didn't like it much) and he changed for BC109Cs after trying it out.

The transistors aren't too important as long as you have fairly high gain.

Enjoy!

johnnyg · Post by **johnnyg** » 13 Feb 2010, 23:01

Hey Mictester - what you've come up with looks really cool man. But do you think it's possible to cut it down to something simpler? I really like the less is more approach and if I can get things down to just a volume knob that's the ideal!

If I lose the big muffy tone stack would this thing still be good to go? And the Abuse control - what would you suggest replacing that with? Also is there no bias issue with this - no need for a bias pot in place of R6 or R9?? (I'm only familiar with ge and simpler si fuzzes).

Cheers!

mictester · Post by **mictester** » 14 Feb 2010, 01:23

johnnyg wrote:Hey Mictester - what you've come up with looks really cool man. But do you think it's possible to cut it down to something simpler? I really like the less is more approach and if I can get things down to just a volume knob that's the ideal!

If I lose the big muffy tone stack would this thing still be good to go? And the Abuse control - what would you suggest replacing that with? Also is there no bias issue with this - no need for a bias pot in place of R6 or R9?? (I'm only familiar with ge and simpler si fuzzes).

Cheers!

Cut it down all you like! The original was built because I wanted more than I could get out of any Fuzz Face. I also liked the flexibility of the tone control and the "abuse" control allowed tones from slightly dirty to downright disgusting at will.

If you want to cut it down, start with the input capacitor choice. Experiment and see what sounds best to you. Next, remove the "abuse" control, and replace it with a (say) 10k preset. Adjust to taste. Remove the BMP tonestack. Take the output from the emitter of the last transistor through a 10µF capacitor to the top of a 47k log volume pot....

The minimum control you can have is the output level control! If you want to get really silly, you could make the output control a preset, and all you'll then have is the bypass button!

johnnyg · Post by **johnnyg** » 14 Feb 2010, 12:34

mictester wrote: Cut it down all you like! The original was built because I wanted more than I could get out of any Fuzz Face. I also liked the flexibility of the tone control and the "abuse" control allowed tones from slightly dirty to downright disgusting at will.

If you want to cut it down, start with the input capacitor choice. Experiment and see what sounds best to you. Next, remove the "abuse" control, and replace it with a (say) 10k preset. Adjust to taste. Remove the BMP tonestack. Take the output from the emitter of the last transistor through a 10µF capacitor to the top of a 47k log volume pot....

The minimum control you can have is the output level control! If you want to get really silly, you could make the output control a preset, and all you'll then have is the bypass button!

Thanks man. I'll dig out the breadboard and give this a try.

A pedal with just a bypass switch would be the ultimate idiot proof effect - so maybe ideal for me

However, although I'm all for economising my builds, I think I'll include the volume knob at least - that's prob gonna end up necessary to get the right balance with different amps and guitars at differing volumes.

keto · Post by **keto** » 17 Feb 2010, 02:15

I don't read schematics very well, though I am learning. I build from known good layouts on perf board. So, looking at the perf layout in the first post, I note 2 things:

1. There is no 1M resistor near the switch, as there (I think) is in the schematic

2) R13 is labelled 0R - is that just a jumper?

Thankee

mictester · Post by **mictester** » 17 Feb 2010, 18:48

keto wrote:I don't read schematics very well, though I am learning. I build from known good layouts on perf board. So, looking at the perf layout in the first post, I note 2 things:

1. There is no 1M resistor near the switch, as there (I think) is in the schematic

2) R13 is labelled 0R - is that just a jumper?

Thankee

Put a 1M resistor from q4 - m4 on the Vero or just tack it under the PCB at the input on that version.

Anything labelled 0R is normally a jumper. I do have some 0R "resistors" (they look like resistors and just have a single black band on them) and they look better on a board than offcuts of wire!

Further thoughts - I just chose a single input cap on the latest build (I won't tell you what type it was, but it was 220nF in value).

Chugs · Post by **Chugs** » 17 Feb 2010, 20:22

i built one of these and it sounds great.

Any suggestions for lowering the amount of gain available at lower settings on the gain knob?

I tried some lower gain transistors but that didn't make a whole lot of difference. My build cleans up pretty nice with the volume knob on my guitar but sometimes, when using the bender for boosting purposes I liked to have have a little less gain on the pedal.

keto · Post by **keto** » 17 Feb 2010, 23:07

mictester wrote: Put a 1M resistor from q4 - m4 on the Vero or just tack it under the PCB at the input on that version.

Anything labelled 0R is normally a jumper. I do have some 0R "resistors" (they look like resistors and just have a single black band on them) and they look better on a board than offcuts of wire!

Further thoughts - I just chose a single input cap on the latest build (I won't tell you what type it was, but it was 220nF in value).

Thanks very kindly for the answer.

I'm building the perf, not the vero. Can I put the 1M EDIT never mind, got it

and your 220nf was in place of the switch + dual cap values, correct?

Last question, will this run on a Boss style negative tip DC adapter?

Edit, OK that wasn't the last. Polarity on the electrolytics? Mostly I can just follow the power in my head, but can whoever made the perf and very layouts please mark polarities

keto · Post by **keto** » 18 Feb 2010, 18:00

NM on the electrolytics, I totally forgot that they are marked with a box for +. C7 isn't marked, but given that one end is tied to the ground I think that one I can figure out

I love the symetry (sp?) of the perf layout. I built it up last night, looks great.

ckyvick · Post by **ckyvick** » 19 Feb 2010, 10:03

If anyone's interested here's a perf layout i did a while back for an si tb, its from dragonflys gallery- http://www.aronnelson.com/gallery/main. ... N.GIF.html
Layout(verified)
https://img705.imageshack.us/img705/173 ... bender.gif

keto · Post by **keto** » 28 Feb 2010, 21:56

OK maybe I don't understand the pull down resistor as well as I thought. I have power to the pedal (added LED, it lights up), bypass works, no output.

This all references the perf build in the first post.

I tied the resistor to ground, then up to a 4-way junction with the switch, the input jack, and C1. I am guessing this is not correct lol. Help?

Also, does the 3rd leg of the toggle switch have to go anywhere (ground or?)?

keto · Post by **keto** » 28 Feb 2010, 22:43

Sorry, no edit button on prior post ???

Never mind. Transistors in backwards.

Volume and Attack both work backwards tho.

mictester · Post by **mictester** » 01 Mar 2010, 02:09

keto wrote:
Never mind. Transistors in backwards.

We've all done that one!

keto wrote:Volume and Attack both work backwards tho.

That depends which way you're looking at them! I usually build my PCBs to that the pots connect straight to the board, and then that can be used as an anchor point to hold the PCB into the case. They look "back -to-front" if you wire then up in the usual way.... Just swap the wires to the ends of the pots, and you'll be OK.