the uglyface should come with a manual ;D

[birt]

Really, chaos like i've never heard before!

after some debugging it does what i suppose it should do.

there's only one thing that bothers me: there is allways sound, it oscillates by itself no matter what.

isn't that only supposed to happen when the threshold is set below some point? it seems to me the threshold knob doesn't do that much, it changes the sound a bit and when set to really the lowest poinnt it can go there's a cool farting sound and sometimes silence. this isn't right is it? that knob should be more versatile i think?

the sensitivity knob also doens't do that much but that probably due to the threshold problem.

i used the perfboard lay-out from home-wrecker.com but without the .001 caps at in and output

[birt]

oh, and is there a difference between 555's? i first tried with a tlc555cp and it didn't work, then put in a philips 555 and i got hit in the face by the volume

[tungngruv]

If I remember right, the volume knob is obvious, the frequency is like a "tone" control,  the sensitivity knob past half way up is an envelope filter and the threshhold starts gating somewhere between 10:00 and 2:00 (I've built two and both of them get the same sounds, just not in the same pot locations). Also, turning up the threshold past a certain point brings the oscillating effect in and then the frequency can control the pitch. It should be quiet (no whining in the back ground until you start the oscillating thing, then you have to back off the threshold knob to get it to stop). I'm thinking a cool thing to do is use two 10k threshold pots connected to a dpdt stomp switch so you can set one to oscillate and then switch to the other pot that is set normally. Now I think of this??? Don't forget when it is oscillating you can bring some of the sensitivity control up and start getting "star wars ray gun" sounds!!! Too much fun!

BTW, your sensitivity should make every note wah when past half way up and the threshold should sound normall up to a point, then start sputtering and gating.
If yours is right, you should have fuzz, gating fuzz, octave down, triggered wah and a tone shift using the frequency knob right off the bat. Maybe make sure the 555 is the right one? I used both devices from Radio Shack and they were fine.

[birt]

well the threshold knob does'nt start gating at a certain point, it does on the whole range

[Paul Perry (Frostwave)]

I just had a look at the uglyface schematic, note it specifies a CMOS 7555, not a standard 555.
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html what a great bunch of ideas here!

[tungngruv]

well the threshold knob does'nt start gating at a certain point, it does on the whole range

Something is wrong then. I would make sure you have the correct 555. RS has them if you are in a hurry, $1.69 Catalog #: 276-1718
(but I would go Small Bear) and then make sure you have the pot wired correctly and that the pot is indeed good. I just had a pot go bad on one of my SkyRippers for no reason. I thought something was really wrong but I changed the pot and all was cool. First time that's ever happened. Is your Ugly Face making the wah sound? Let me know and good luck!

[Tim Escobedo]

The Threshold control is simply a voltage divider connecting V+ to ground. Pin 4 of the 7555 chip is the "Enable" pin. That means if it's above a certain voltage (ISTR about 1-2V), the 7555 chip will become a oscillator. If pin 4 is below the threshold voltage, the 7555 chip is essentially "off".

If the circuit won't stop oscillating, perhaps the voltage divider isn't connecting to ground. Or possibly, the output of the 386 chip is direct coupled to pin 4. Also, be sure to use a CMOS 555 chip, such as the 7555, TLC555 or TS555, as stated on the schematic. I only briefly tried a regular 555 in the circuit once long ago, it clearly didn't work as intended, and I chose to specify the CMOS 555 chip.

[soggybag]

I think this is a great effect. I have built three so far. I used the RunoffGroove .001 caps and all of them.

I find the threshold knob to be kinda on or off. about half way up it starts to oscilate. Other than that the effect is very sublte. The sensitivity knob has a lot of use.

[birt]

The Threshold control is simply a voltage divider connecting V+ to ground. Pin 4 of the 7555 chip is the "Enable" pin. That means if it's above a certain voltage (ISTR about 1-2V), the 7555 chip will become a oscillator. If pin 4 is below the threshold voltage, the 7555 chip is essentially "off".

If the circuit won't stop oscillating, perhaps the voltage divider isn't connecting to ground. Or possibly, the output of the 386 chip is direct coupled to pin 4. Also, be sure to use a CMOS 555 chip, such as the 7555, TLC555 or TS555, as stated on the schematic. I only briefly tried a regular 555 in the circuit once long ago, it clearly didn't work as intended, and I chose to specify the CMOS 555 chip.

the voltage divider is connected to ground. Isn't the output of the 386 allways going to pin 4 of the cmos 555 (thru a 2,2uf cap) and to the voltage divider?

i first used a TLC555CP and all i got was a really quiet sound, with the volume maxed out!, then i put in a philips NE555N and i got lots of volume so i figured that would be a good chip?

[birt]

just saw the datasheets, the NE555 isn't right. but it gets me all the sounds except for the threshold problem, i think i got a bad CMOS TLC555 chip. i'll have to get another one

[jmusser]

I believe it's Runoffgroove that has a nice article on the Ugly Face build, using just about all Radio Shack parts, including the photo cell/LED optocoupler. There's several mods around for this too. There's one that supposed to sort of give you a "bagpipe" effect. I have the article and the sound sample for it somewhere if you're interested.

[tungngruv]

I also used the "bagpipe" mod and while it's cool, I never seem to use it. If you make the uglyface oscillate, then tune it to lets say, a "D" note (or any note you choose), you can then play other notes while the "D" is droning in the background.  While it does work, I could never get really great seperation of both notes.