Why build them at all
phase shifter info and demo
Envelope Follower: "Dr Q" w/ demo


I mean, why build them at all? Aren't they teeny-tiny, requiring itty bitty hands, isn't the smoke from solder bad for you, doesn't your wife get pissed at you for swearing because you can't figure out why the thing doesn't work? (yadda yadda).

For me, this was entirely a learning experience. I wanted to learn more about how the great analog electronics of my youth worked. Besides, one might argue:you can build a very close duplicate pedal for less than it costs to buy a used "vintage" one. If you're OK at soldering and tinkering with electronics, you can do this, and I found it's fun too--when the things works. There are plenty of good web sites that can help you buy the stuff, put it together, and troubleshoot it. And of course you can modify it, substitute whatever parts you want (a heavier duty case, for instance) etc. etc.

As I get the time I will post whatever info I learned from these building experiences here so the next person trying to get this to work will hopefully find joy quicker than I did.


Based on the SMALL STONE design, this uses 4 3080 OTA chips for the phase sound. You can hear a demo I made of it here.

I bought the circuit board from the now defunct guitar-kit.com (at least their site is gone). If anyone knows where you can get this board still, let me know. OK, after getting info from the most-excellent site tonepad.com.

There is also really good info about Small Stones on JD Sleep's General Guitar Gadgets site.

In general, this was not too easy a pedal to build, owing partially to my own moderate skills with electronics.

I first couldn't get the thing to work since I had some of the 5087 transistors where the 5088's should go...oops. OK, that was easily solved, but I found after that the stupid thing went CLICK CLICK CLICK in the audio output, which I was sure was due to another MISTAKE somewhere in the build. I could see the LFO's signal ALL OVER every trace on the thing it seemed when I used an oscilloscope.

After some research, emails, and some help from a real tech I know, it became OBVIOUS that I should include the Ca and Cb caps on the tonepad site, even though the board I bought didn't have holes for the 47uF "Cb" cap. Apparently these caps were added later and consequently some earlier versions of the PCB didn't have provisions for the cap. Anyway, I used 47uF on the board, and 10uF non polarized 100V for the DPDT switch's cap. This calmed down the ticking, in fact, as far as I can tell it's gone.

Some more mods I did: R24 can be messed w/ to control speed range, but I came back to 100 ohms; 10K trimmer instead of R11; 2K resistor in series w/ 5K linear pot instead of R42; turn the pot all the way up and then adjust the trimmer until right before the unit feeds back. Go back and forth between full bypass and no-bypass in "color on" mode with the color knob turned all the way up and make sure you don't hear any leakage of the circuit in "bypass"--if you do, crank the feedback down some more. Now you have a pot to control COLOR that sounds very cool, especially when cranked all the way up.

ABOUT THE DEMO: A 8 bar loopy thing I did using telecaster, an adat, and the phase shifter I built. Took about 2 hrs to do the demo, start to finish, which is a heck of a lot less than it took to build the pedal!!! All the sounds you hear (there are some subtle vocal and sample thingys that are hard to make out if you have small speakers on your PC) are processed through the phase shifter--it seems to be a useful unit, although the noise floor on it is awful, making it a bit hard to record. Also note that this pedal seems to do some wacky things with tuning....in some ways it's more like a chorus unit than a phase shifter....thus the pitch of the tele was warbling all over the place, but I guess in some situations that isn't all that bad.


STOMP BOXES: Dr Q Envelope Follower!

MP3 demo of Dr. Q is here.

Another favorite of mine was the EH "Dr Q". This was EH's envelope follower....not good for everthing--it's a pretty specialized, disco-esque sort of sound.

Many sites tell you not to build the exact Dr. Q thing since it the original design was a bit cheesy, but recommend a revised design called "Dr. Quack". OK, so I built the Dr. Quack. There's lots of good Dr. Quack info on the web, but once again the JD Sleep General Guitar Gadgets site was home base for me on this one. The link is here. If you search on google for Dr. Quack Envelope you can find more.

What I learned: First, don't ever, EVER use radio shack perf board. It will melt on you and make you cry. Also, I got a quick "doooh!" lesson in properly identifing capacitors: 104K is .1uF, 103K is .01uF, and 102K means .001uF. In general I found perf-boarding to be tricky, and found later efforts using custom, home made Printed Circuit Boards easier to get going and produce more reliable results. If I were to do this again, I'd use the PCB's.

As far as mods, I included ALL of them from the general guitar gadgets site. This includes the "delay" capacitor; a switch to adjust for different guitars, etc. Make sure you use identical, red LED's for this, and no, they do not light up (not brightly, anyway), they are just there to make the circuit work. You can leave them inside the case. If I were to build it again, I'd add some sort of simple gain/cut stage instead of the input buffer that's in there, so I could use more disparate instruments at its input....as it is now, I have to mess around with volume levels a lot going into the box to get it to sound decent.

About the demo

Except for the drum machine, everything you hear is Dr-Quacked. The tune is of course Herbie Hancock's "Chameleon." I Dr-Q'd a Rhodes sample, a brass synth thing, a odd doodoo-electric piano sound, a Clavinette, a few guitars, etc. The guitar solo is a Les Paul that has been quacked--anything single-coil I have doesn't sound as good through the Dr. Quack, even with the "hi-low" input mod in there.