Successful first build - Tweak-O Pedal

GussyLoveridge · Post by **GussyLoveridge** » Sun Dec 04, 2011 5:55 pm

So - after many years of fixing cables, rewiring guitars, repairing pickups and all that stuff, I finally got around to building something. I went with the easiest kit I could find to start with. I picked up a Tweak-O kit from Small Bear. I had such a fun time working on this, I honestly couldn't have had a better time. Now I'm wondering what to try next. Thinking maybe a B.Y.O.C. Classic Compressor stomp box. But, I'm open to suggestions. A few other things I'd like to build would be:

Headphone Amplifier
Reamp Box
Phono Preamp
DI

Anyway - Here is a link to some photos Oh yeah, it works too!

http://www.flickr.com/photos/gusloverid ... 228388521/

Nate Dort · Post by **Nate Dort** » Sun Dec 04, 2011 8:07 pm

The New York Dave reamp box is pretty simple and really handy.

GussyLoveridge · Post by **GussyLoveridge** » Mon Dec 05, 2011 10:06 am

Hey Nate - Thanks a lot. That looks pretty awesome, maybe that's next.

Darlington Pair · Post by **Darlington Pair** » Mon Dec 05, 2011 12:56 pm

If you're not already a member I highly recommend joining the forums at Diy Stompboxes, there are a bunch of really great, helpful people over there when it comes to pedals and many other surprising things.

Peterson Goodwyn · Post by **Peterson Goodwyn** » Tue Dec 06, 2011 12:19 pm

A reamp box is even easier if you leave out the volume and impedance controls, both of which I find to be unnecessary. Then you're basically left with this:

GussyLoveridge · Post by **GussyLoveridge** » Tue Dec 06, 2011 12:29 pm

Peterson Goodwyn wrote:A reamp box is even easier if you leave out the volume and impedance controls, both of which I find to be necessary. Then you're basically left with this:

So you're saying you wouldn't build one without the volume and impedance controls?

@ Wavley - Thanks - I'm checking them out now.

Peterson Goodwyn · Post by **Peterson Goodwyn** » Tue Dec 06, 2011 12:46 pm

Oops, I meant "uneccesary."

GussyLoveridge · Post by **GussyLoveridge** » Tue Dec 06, 2011 5:14 pm

Okay - so on messing around with the pedal for a couple days, I'm super happy with the way it sounds, but it doesn't really boost so much. It seems that the apparent loudness is lower when the pedal is engaged even with the fuzz and level dimed. With the fuzz - as you begin to bring it from off to fully engaged, it seems to get a little quieter in the last 20% or so.

Ideally I would like to have this be a very obvious boost. Here is the schematic, it's pretty simple. Looking for ideas on how to remedy it.

http://www.flickr.com/photos/gusloveridge/6468914867/

Jim Williams · Post by **Jim Williams** » Wed Dec 07, 2011 9:04 am

You can't expect too much from a single transistor. If you just want boost, pull out the diodes. If you need gain, lots of it, use a high beta transistor with low noise like a 2SC2545 or 2SC3329, even a MPSA18 will work.

For clean boost pedals, an opamp seem to be the best solution. If you want to have more fun with vintage designed fuzz tones, that Fuzz Central site has most of the classics listed. I built a Colorsound Tonebender (amazing 60's fuzz) a Foxx Tone machine with that great octave split, a Fuzz Face, and a Roger Mayer Octavia. Rather that bother with pcb's, I just breadboarded these together, pretty easy. I used all original AC128 germaniums and older 2n transistors for authenticity.

I used colored 1592BB sized boxes from CE Distribution, those only cost $5.99. Each has a color matching LED indicator, they look like candy on the floor. Add some CTS pots, 3PDT footswitches and switchcraft jacks and these are indestructable.

germaniac · Post by **germaniac** » Wed Dec 07, 2011 6:02 pm

Hi Gussy,

Glancing at the schemo, I'd say a quick way to get more gain would be to swap the positions of R5 and R6. Doing this will bring the output leg closer to the xstr's collector without changing the biasing (which is important). You should have plenty of gain then. However, I'm guessing this might also darken the sound a bit due to changing the roll-off point of C6. If the sound is too dark after swapping those resistors, try halving the value of C6 to .0047. Hope that helps!

Joe

Darlington Pair · Post by **Darlington Pair** » Thu Dec 08, 2011 7:02 am

Double the diodes (in series) in the feedback loop, you will get less distortion but more signal, instead of clipping at .7 volts you will clip at 1.4 volts. You can also use different diodes for asymmetrical clipping, like a red led on one side and a germanium on the other.

It's also true that there is only so much you can get out of a single transistor clipper. You can try switching to a higher gain transistor, but for the most part you will just change how much distortion you have because you are limited by the clippers in the feedback loop and there is nothing for make up gain, you would need a second transistor for that.

Jim Williams · Post by **Jim Williams** » Thu Dec 08, 2011 7:59 am

All of the favored fuzz boxes are a two or more transistor design. The early simple designs like the Vox distortion booster (which led to the Fuzz Face) had two, the tonebenders used 3 and that Foxx used 4.

The reason is because one transistor won't have the gain range and output drive. The other reason is tone, saturate one transistor and it sounds clogged, like it's trying to get the sound out but can't. Favored designs including tube guitar amps used a gentle cascading distortion, with one stage gently clipping into the next. That prevents device overload and that falling apart sound and creates the distortion most players favor, Neal Young withstanding.

If you need a clean boost pedal, do up an opamp design. I have those mounted inside all of my guitars, they give me that line level output that drives amps hard, low impedance that eliminates cable effects and that bell like tone that gets lost after a 20 foot run. They preserve the guitar pickup's resonant peak without the roll-offs that occur using passive volume/tone pots and a 20 foot cable = low pass filter.

Snarl 12/8 · Post by **Snarl 12/8** » Thu Dec 08, 2011 8:55 am

Jim Williams wrote:All of the favored fuzz boxes are a two or more transistor design. The early simple designs like the Vox distortion booster (which led to the Fuzz Face) had two, the tonebenders used 3 and that Foxx used 4.

The reason is because one transistor won't have the gain range and output drive. The other reason is tone, saturate one transistor and it sounds clogged, like it's trying to get the sound out but can't. Favored designs including tube guitar amps used a gentle cascading distortion, with one stage gently clipping into the next. That prevents device overload and that falling apart sound and creates the distortion most players favor, Neal Young withstanding.

If you need a clean boost pedal, do up an opamp design. I have those mounted inside all of my guitars, they give me that line level output that drives amps hard, low impedance that eliminates cable effects and that bell like tone that gets lost after a 20 foot run. They preserve the guitar pickup's resonant peak without the roll-offs that occur using passive volume/tone pots and a 20 foot cable = low pass filter.

Would you share the schematic of what you're putting in your guitars?

germaniac · Post by **germaniac** » Thu Dec 08, 2011 12:36 pm

Hi,

Regarding classic fuzz circuits, a friendly caveat to anyone considering using a guitar with active electronics: this will totally change the sound and dynamics of a Fuzz Face or similar circuits. And the difference is not some subtle, mojo-obsessive, only-Eric-Johnson-can-hear-it sort of way. The reason for this drastic change is because the sound of Fuzz Face-type circuits is largely defined by their very low input impedance, much lower than is common practice in modern effects. Of course, whether you like the change in sound is entirely a matter of opinion. . . .

Joe

GussyLoveridge · Post by **GussyLoveridge** » Thu Dec 08, 2011 2:04 pm

All of this stuff is super great guys. Thanks so much for the help. Not sure now if I'm going to try and mod this guy or just start into something new.

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Successful first build - Tweak-O Pedal

Successful first build - Tweak-O Pedal

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