Uglyface info required

[Mick Bailey]

Just completed an Uglyface build and whilst I really like the sound I would like it to be a little less glitchy. I've now got a .01uf cap across the input and this has helped a lot, as has using the neck pickup with tone rolled off.

The IC I'm using is an LM386N-1 and I'm wondering if a JRC386 would be better - has anyone A/Bd these and found a difference? The JRC IC seems difficult to obtain in the UK.

[smnm]

I doubt they 386 brand is crucial as this thing is mostly about noise, but you could try the 'mix mod' (do a search) if you want more versatility...
I haven't done it myself, but others seem to like it.

[signalpaths]

I just built that too and the sound is cool but a little harsh at times.  Most of the magic in that pedal IMO is happening via the 555 pulse being added to the signal.  The amplifier is what is adding the gain so i was thinkin g it would be possible to  set up a different gin stage that would be less harsh possibly similar to a TS.  That is as far as i've got but maybe this weekend if I don't have too much homework


Eric

[Mick Bailey]

I doubt they 386 brand is crucial as this thing is mostly about noise, but you could try the 'mix mod' (do a search) if you want more versatility...
I haven't done it myself, but others seem to like it.

What I'm looking for is a more stable sound - my pedal 'warbles' between two pitches, like it's mis-tracking. I like the synthy sound of the pedal and don't think I'd go for the mix mod. My pedal's already pretty cramped due to adding another PCB and control for LFO speed and switches for LFO/Envelope and ramp up/triangle/ramp down. BTW, it mis-tracked before adding the LFO.

Referring to Tim E's circuit snippets; "The JRC386D aka NJM386D (used in the Smokey) seems more stable and easier to tame than the National Semiconductor LM386" It was this that got me thinking that it may improve with an IC change. I'd like to find out what anyone else's experience is with this, as it looks like I'd need to order (and pay postage) on buying from Germany to get a JRC386D, which is an expensive way to experiment if it makes no difference.

[Mick Bailey]

Any chance someone could shed some light on the JRC386 issue before I commit any hard-earned cash? has anyone tried both ICs?

[jefe]

Sorry I can't shed any light on the JRC386D vs. LM386. Where are you located? I know that Smallbear carries the JRC386D. I bought a few, and plan on testing them against the LM386 in a Ruby Amp, Smash Drive, and most likely an Uglyface. I also recall that some people prefer the JRC in a Ruby.

[Krinor]

I have A/B'ed JRC386 vs LM386 i a Ruby, and the JRC really shine. LM386 is fine, but the JRC version has a noticeably better sound in every way IMO.
I'm just about to build an Uglyface myself, and will try both IC's and report back if I notice any difference between the two in this circuit.

[Mick Bailey]

Thanks for the info - I'm in England and the JRC only seems to be available from Germany, but seems it may be worth ordering a few.

I've done a few mods to the original design to improve the depth of envelope sweep, provide better threshold range, better frequency control and tame the (very) high output. I've also added an LFO which expands the range of sounds enormously.

Will post the info shortly.

[Mick Bailey]

Uglyface LFO & mods as promised........

http://www.avwz35.dsl.pipex.com/uglyface lfo & mods.jpg

Study this in conjunction with Tim's original schematic. Essentially, the LFO switch replaces the envelope feed with a modulated voltage applied to the sensitivity pot. This then controls the depth of modulation when in LFO mode. The power is switched off to the LFO when it is disconnected to prevent bleed-through into the rest of the circuit, though this in itself is an interesting effect as you get LFO and envelope at the same time if the power isn't switched.

The Frequency mod gives better and more reliable sub-octave effects. The 22k resistor evens out the volume across the range of the control.

R6 is needed to regulate the overall depth of modulation to the optoisolator (vactrol or LED/LDR pair). I used the LED/LDR route and 1k worked out fine. I soldered in a trimmer, got the right depth, then replaced it with a fixed resistor. You need to trim it so that at maximum sensitivity it just about overmodulates with the LFO set to about 1Hz.

The threshold resistor change gives better control over triggering by extending the pot's range of pre-oscillation travel.

Inserting the 220k resistor makes the volume pot usable and sets unity gain (with an LM386N) at the halfway mark.

Note that the ramp up/triangle/ramp down switch has to be centre-off (sometimes listed as 1-0-1). If not, you'll only get up/down effects.

[GREEN FUZ]

Thanks. Think I`ll give these a go.

[Mick Bailey]

Just got my JRC386Ds from Banzai in Germany. With bulking up to minimum order charges and postage, it cost me £8 to get one (about $16 at current rates).

So I was pretty expectant - thought there may be some wonderful improvement.

No. And I tried four different ones.

I've reverted back to my original LM386N-1. It provides better sweep characteristics, better frequency control, more musical range of sounds and better sub-octave tracking. I suppose on the plus side, the JRC is louder and gives better clarity. I'm not convinced overall, though, and put it all down to experience. You live in hope and die in despair.

Your mileage may vary.

[big bustle]

OMG this looks so awesome!

any chance you could work this into a usable perfboard layout?

thank you so much for this info i am trying excited to see if i could get this to work

[big bustle]

here's my attempt at a layout for a small bear 15x15 perf board.

i'm sure it can be improved . i'd be glad to send the diy layout creator file to anyone interesting in taking up this task.

so i have a few questions:

r5 says 100r. i assume thats 100ohms?

did i get the pots right? i always get confused looking at schems to decide which one is pin 1.

anyone have a song to help remember this stuff?

[soggybag]

I have been working on my own Ugly Face LFO. I'll post a drawing, for fun and coparison, when I get a chance. I had been planning to nix the Threshold control. But after looking at your plan, I think I keep it and try your mods.

[FisTheGoon]

Wow.  seem interesting.Care to post some sample clip of the design? 

[Mick Bailey]

100R is 100 Ohms.

I'll try to put some clips together.

I often get the outer lugs reversed with pots, so I'm not one to give advice on this!

[big bustle]

does everything else look ok on this?

[andrew_k]

Excellent looking LFO mods; I'll have a go at a complete layout this weekend as I'm putting together a large noisebox project that includes a joystick-controlled uglyface 

[big bustle]

i think there are a lot of folks that would be interested in seeing this info. is there any way to re-title the thread to something like "uglface lfo schem and layout"?

so can any one else use their amazing powers of abstract thinking and verify if layout matches the schem?

[andrew_k]

so can any one else use their amazing powers of abstract thinking and verify if layout matches the schem?

On your LFO layout C2, R2 and pin 4 are not connected to ground.