The Uglyface effect is an oscillation based distortion/fuzz pedal with envelope controller designed by Tim Escobedo. It can do a wide varitey of off the wall sounds (laser guns, bagpipes, drones), and it has many different ways to modify the circuit. I’ll liked it so much I built it into one of my old junker guitars (details below).

This is the first Uglyface I’ve built. I built it into some crazy electronics box with huge heatsyncs on the sides. Seemed to fit the circuit some how lol. I did the standard controls of Volume, Threshold, Frequency, and Sensitivity, and added a mix control that worked ok.

I had this old guitar knocking around for a while, so I decided to mount an Uglyface inside of it. It has all the same controls as the pedal above, but I also added a Light Sensor with switch for controlling the frequency knob.

PSS-270, 170, 140 and SHS-10 Tutorial

After some major diggin’ for info I found that no one had a specific guide for bending a Yamaha PSS-270, so I decided to make one. Credit to Sean “audioid” (, and Paul from for the info on this bend. This bend involves cutting data lines that go from the FM synth chip (YM2413) to the main chip (XC194A0). The pins on the FM chip that go to the main chip are pins 2, 3, 4, 5, 6, 7, 17, and 18. You cut the traces, and then solder wires on either side of the cut. Take the pair of wires from one cut, and solder them to a switch, and this will allow you to turn the flow of data on and off.

This is a picture of the board flipped over. I have the FM chip out-lined in red, and you can see the big chip under it.







In this picture I have the solder points from the FM chip marked in red dots, and the blue dots are where they go to the main chip. Ignore the green dots. The black line is where you *carefully* cut the data lines. I used a volt meter to check and make sure that the lines no longer had continuity.






I’ve indicated the FM chip in this picture.








Here’s all 16 wires in place. Some people recommend drilling very small holes on both sides of the trace cuts, and putting wires through them, or scraping the coating off so you can solder on it. I just soldered the wires onto the pins of the chip, which can be dangerous because you run the risk of overheating it. I used a pair of wires that are the same color for each connection to make wiring up the switches easier.





I’ve got the board back in place, and the wires bundled up nice and securely.







Now all the switches are wired up, and we are ready to button her back up.







I found the most room for the 8 switches on the right side of the keyboard. Just measure and drill carefully, and it will come out looking great.






What the Bends do:

Each switch now controls the flow of data from the FM chip to the main chip. Turn the PSS on and select a patch (let’s pull up #89 “ghost”), I usually play some keys(don’t know if you have to do this or not), then turn some switches off , now select a different patch, and turn the switches back on. Now try playing the new patch. If it went well some of the data from the all patch got held up, and then inserted into the new patch making a totally different sound. Sometimes leaving the connections off will change the sounds also. I’ve noticed them some of the bent up patches will only work when multiple keys are played. I’ve heard that this will effect the drums as well, but I haven’t gotten it to do much with them as of yet.

Getting some good sounds out of this takes some tinkering, but it’s worth it. The only downer is that it’s hard to reproduce the sounds that you get, so if you have a good one be sure to grab a sample while you can. Using the keyboard this way can corrupt the data to the point where the chip crashes in a noisy mess, but all you have to do is turn all the data connections back on, and turn the keyboard off, then back on. All the data connection switches have to be on for the keyboard to work “normally”.

John from Bentpedals sent me these photos of a PSS-140 that he did up using this same mod. The main chip is colored in red, the FM chip in blue, ignore the yellow.






I did the mod on a PSS-140 for Mjm using the info that John gave me. This is what he had to say about it “endless amounts of fun. endless unpredictable possibilities. i don’t want to stop messing with it”. Here’s some photos of that.

Wesley did the same mod to a PSS-170, but his link seems to be dead.


 I’ve successfully done this on a Yamaha SHS-10 Keytar , along with some other circuit bends. Tinsoldier sent me a diagram of his circuit bent SHS-10 which I will post here. I can’t comment on it at yet because I haven’t had the chance to try them myself.








As always I won’t be held responsible if you try this bend and your Yamaha get’s hurt. I’ve done a lot of playing with this keyboard, and it seems real solid to me. This bend works on some of the other PSS series keyboards (like the 140) with a similar chip setup, but since I’ve only done a 270 and 140 so far I can’t gurantee it will work on all of them.

Furby Bending Tutorial

Since I’ve been asked many times about bending furbies I thought I would make this guide to help those that would like to give it a try.

This furby is in the typical shape I find most of them in. Let’s take away his dignity further by striping him of his fur.

This lump on his bottom side is where there is a strap tie holding his fur on. Cut this, and pull the tie strap out.
Furby 3
Roll his ears back and cut the threads holding them on.

I usually roll his fur up along his body so we can expose the screws holding his face piece on. Remove the screws, and there will be some hot melt glue attaching the fur to the top of his head. With some light tugging the fur should free and then you’ll have your very own naked furby. Remove all the screws from the carapace, and it will come apart in 2 halves.

See, look at how liberated he is to be freed of that cumbersome fur.
Furby 6
You have to take off the speaker/tummy switch to be able to tilt his battery compartment over, and get to the circuit board underneath. This is also a good time to add wires to the speaker for your output jack.
Furby 8

I’ve found a stable glitch, and loop bend that stem from the same common point. I have the common marked in red, the glitch in blue, and the loop in green. Your mileage may vary from one furby to the next. On this particular furby I used a 47 ohm resistor in line with the glitch wire to make it a little more stable. I’m sure that there are more bends in a furby, but I haven’t dug to deep because I’ve heard that these fry easy.

The bending has changed him some how….

I normally run the bend wires along the right side of the furby up to his head. There is a small area on the back of a furbie’s head where you can drill a hole, and run the wires out to a control box. I normally set it up with a switch for the glitch bend, a normally open push button, and switch for the loop. You use the push button to find a loop you like, and then flip the switch to lock it in.

I’ve had a lot of people ask me about the way the loop section is wired, so I made up a nitty gritty diagram in MS paint. I still have the wires colored the same as in the circuit board diagram. Basically what’s happening is that you have the same connection wired to 2 different kinds of switches.


As always I won’t be held responsible if you try this bend and your Furby get’s hurt!

I’ve done quite a few furbies now, and I always try to make each one unique to the others. I’ve played around with decorating them in strange ways, and I built one that has all it’s bends controlled by an Atari style joystick. I’m going to post some pics of a few of these on this page.