Craig Anderton Super Tone control build report with Pics and clips

[John Lyons]

Just finished building the Craig Anderton "Super Tone Control" from his book Electronic Projects for Guitarists.
The circuit is a simple "State Variable Filter" with High, mid/band and low pass filters.
There is a Resonace control as well which sets the sharpness of the filter.

I built this one into a foot controlled unit and with 2 adjustable and selectable "Preset" knobs for fixed wah/filter sounds.
The Knob on the left bottom by the stomp switch is a rotary selector which selects preset A, B or  foot rocker control.
This circuit can be controlled by an envelope follower as well. I chose to keep it manual and foot controlled for a static/manual filter or a more wah like operation.
The Setup for recording this was a 70's strat single coil with the bridge PU, Jack Orman's "Fat Gnat" distortion, and a 70's twin reverb. Sounds a little fizzy to me on this recording compared to in person....

There is a lot range to this unit. The foot controlled wah can get quite funky and Mutron like as you can hear.

I used a NTE997 chip that is the equivalent to the 4136 the circuit calls for.

Here are a couple Sound samples and a pic of the inside and outside.

Soundclips:

Wah type sounds
http://www.mrdwab.com/john/Supertonewahdist.mp3

Sweeping through frequency knob settings
http://www.mrdwab.com/john/Supertonesweep2.mp3

Clean wah sounds
http://www.mrdwab.com/john/supertonecleanwah.mp3

More filter changes
http://www.mrdwab.com/john/supertonesweep.mp3

The wah shell is a bit odd. I picked this one up a local guitar shop. It was used as a machine speed control and someone thought it was a wah so it ended up in the shop somehow, I love used mom and pop shops! The nylon bar rocks on the metal rod which has spring loaded tips that insert into the shell of the top piece to hold it in place. This unit is very heavy duty all metal construction (except for nylon fulcrum piece) including the gear.

John

[toneman]

VERY NICE !!  Recycling effort!! 

The STC is a very nice SVfilter.

The first link doesn't work 4 me.

Sure beats the mojo price of a Mutron.

Again, Nice construction work!!!

[John Lyons]

Thanks Toneman

I fixed that link (which I think is the best one) check it out
There are always things I wish I could do better but I think it turned out nice.

John

[dano12]

Awesome. A great circuit with some cool parts recycling thrown in. I have that book--I should build this!

Nice clips too. Thanks for sharing.

[John Lyons]

I built this one for a guy, shipping it out already. I think the next one will be a fixed version...although the foot control is key to the wah sound and sweeps...  the sweep depth was pretty large on this one. Most wah shells don't have a full range for the pots rotation. Maybe just take some of the bass side away and hav the sweep more in the low mid to treble areas...

ALso, I had planned to have the presets selecable by stomp switch but the wiring was too crazy and I don't have the chops down on CMOS switching logic yet. It would have taken 2 4PDTstomp switches...$$$$

Smallbear should be able to get use some cheaper wah shell and pot combos soon.

John

[disto]

wow very nice!

The wah shell is a bit odd...

a bit odd!!! it looks good! im impressed was the gearing already in there or your own design?

[John Lyons]

The wah shell was ready to go as I found it...I just added the dual 50K pot. I couldn't find a any dual long shaft pots so I made a D shaft pot out of a round one and made a D shaft out of a lenth of another shaft and grafted them together. The metal gear with set screw helped out here as it clamped them both together nicely. I had to move the Nylon lever over a but because the pot was an 1/8" too short.
I wish I had a few more of these shells!
I was sad to see it go.

[Mark Hammer]

One of the neatest sounds I ever got from mine (and one of the primary reasons I'm rebuilding it), is sweeping the highpass filter downward.  The closest recoded example I can think of is that old nugget by The Fixx, called "One thing leads to another", where there is an extremely funky downward filter sweep with lots of resonance.  Since it is easier to regulate the expressiveness of the sweep movement when moving your foot forward than when moving it backward, a useful addition to a treadle-operated version of this or similar SVFs is to include a direction-reverse switch that swaps the outside lugs of the two pot sections.  That way if your desire is to control how you sweep upwards, the filter-frequency pot/s will be oriented properly, and if you decide you want the filter to sweep downward, you can do that too.

The caveat is that you need to use a linear-taper pot if you want to have the same degree of control going in the one direction as in the other.  But for playability, can't be beat.

Nice sound-clips, incidentally.

[Arn C.]

Nice work! Nice clips!

I have a few of those pedals also.  Used ones.  Our company uses them for the speed control on our winding machines.  Winding copper for motors.   LInemaster Switch Corp makes them.  I think they are still in production.  The ones I have are called  "Varior II  Variable Controller.  I've made a wah and a crybaby with two of mine.

Peace!
Arn C.

[disto]

i have just been looking at the LInemaster Switch Corp site and the products they produce.

EXPLOSION PROOF 500 Series - doesnt that sound like it could make one hell of a pedal, infact it would be very unpracticle i think, sounds cool though. 

[John Lyons]

Arn
Yes, this are cool wah shells...or can be. I don't suppose you have an extra one you would like to trade/sell? I made this one for sale and it's alreadt gone! It's built like a tank and ist super heavy duty to say the least.

Mark, yeah I know what you mean about "that" setting and the song reference. The switch reverse idea is a good one.  I'm already iching to make another...

[MartyMart]

Fantastic build and clips   ..... I'm blown away, that's the most fabulous Wah/Sweep that I've
heard in ages !!
..... the list goes on and on ... 

MM.

[John Lyons]

Listen to mark Hammer. He's talked about this circuit for a while now.

The sounds clips (flexi record..yeah!) in the "Electronic projects for guitarists" book are pretty dismal in a real world/guiar amp way but you can hear how much this sucker can sweep. Didn't help that Craig Anderton used an organ to record that particular sound clip.

Thanks for the compliments folks!

John

[Mark Hammer]

Thanks for the nod, BA.  Much appreciated.

There are, as noted, two versions of the Super Tone Control, one with level pots instead of toggles, found in EPFM II.  Between the 1st and 2nd edition of the book, Craig realized it was possible to make a simple change to the circuit that would expand the sweep range of the frequency control.  You can find details on page 13 here: http://hammer.ampage.org/files/Device1-8.PDF

Here's where it gets interesting.  In EPFM I, the double-ganged pot for frequency control was wired as a dual variable resistor, and absolute pot value was important, the same way that LDR specs are important for a Mutron or Meatball.  In EPFM II, he realized that a voltage divider could be used for a wider range, but the pot value could range between 10k and 100k.

Why is this important for you?  Because it affords the ability to tweak the range so that a wider frequency sweep can be produced with little foot movement or, conversely, full treadle movement is required to cover only limited frequency range.  Both of these will be useful for somebody, and maybe even for the same person.

If you had a dual-ganged 10k pot, increasing the value of the resistors to ground (33R in the picture shown above) would alter one limit of the frequency-sweep, and inserting a resistance in series with the input of the pot would limit the frequency sweep on the other side of the range.  The ideal would probably be a 3 double-ganged-pot arrangement, whereby one double-ganged pot is used as an adjustable series resistance on the input of the foot-swept pot, and another is used as an adjustable resistance to ground.  If each of these were set to maximum resistance, then the foot-swept ganged pot would essentially cover the middle third of the "potential" sweep of a virtual 30k pot made up of these three physical pots.  Since virtual pot values between 10k and 100k are valid, combining these three physical pots is well within limits, and will provide all sorts of adjustment of both where in the frequency spectrum the filter does its business, and how much "business" a front-to-back (or back-to-front) foot movement will accomplish.  When combined with the suggested sweep-reverse switch, the user can achieve all manner of wah functions and degrees of expressiveness.

Case in point where the range-adjustment is useful.  When the lowpass filter is swept, going from low to high increases bandwidth, but hardly ever omits the fundamental.  If the pedal is in the bandpass or highpass mode, however, if you sweep to high, you lose the fundamental, and you get a huge volume drop.  By being able to adjust the upper and lower limits of sweep, you can assure that you never lose too much fundamental and volume in that mode.  Certainly, there are instances where you'd want to sweep downward from way up high in the highpass mode, and gradually bring in upper harmonics and eventually mids and lows.  But that's the whole point of this suggested mod.  You get to choose which way you want to use the pedal, not just get stuck with one.

[John Lyons]

Yes, surely a lot of possibilities here. I got a litle bogged down with my build,  I wanted to have Footswitchable Pot A, B, or  Footcontrol of the Frequency sweep. I ended up using a rotary 4PTT (four pole triple throw) which kind of saved my butt because I was trying to use two foot switches iside by side stomped in unison to do two sets of switching (a DPDT and 3PDT which would switch with the same footswich asction) ...A nightmare, it wont work. Maybe with a 4PDT you could do it but without an LED... I'll try to get my head around CMOS switching and we'll see.

I used a 50K dual pot and a 68 ohm resistors to ground for mine. There was a small dead area around the low end of the seep which went away with doubling the 33 ohm schematic recommendation to 68 ohms. Although CA talks about varying the value for larger pots so there you go...
Interesting about trying the taper to the input side as well as the ground side Mark.... Now I'll have to build another.

John

[jbefumo]

Old thread, I know, but anyway:

I built this long ago, combined with the Envelope Follower from the same book, and the result was the most awesome auto-wah ever. I sold it years back and have regretted doing so ever since. I finally got around to building another, and just tracked down a pair of Clairex CLM-6000s, and will be building another in the near future.  Will post a vid when it's done.

[Mark Hammer]

I've got a partially completed one in an old wah shell that is awaiting me finishing a bunch of other things on the stack.  Not sure what I did with my original one, but I miss it and am looking forward to reviving it.

[StephenGiles]

Very nice samples, I'm sure that I made this back then but it's whereabouts has beaten me!

[snk]

Hello,
I am ressurecting this thread, because i have built an Anderton Super Tone Control (using this layout).
It works very well, and i enjoy the sound a lot. But i have an issue : with some settings (quite often), it produces some whining, high frequency noise.
I have searched a bit for possible reasons (verifying that i am actually using a 7760S, and not a regular 7760 chip, for instance, or shielding the wires going to the resonance pot), without suceeding.
I am wondering if anyone around here would know what can cause such an issue ?