DIY Rat, distortion button strangely behaving.

[Sabudum]

Hello, i've been building a DIY Rat, the original one.
Tha project is La RATA from TOnepad:
http://www.tonepad.com/project.asp?id=45

With this schematic:
http://www.tonepad.com/getFile.asp?id=89

I created my own layout, as i have no condition of buying a ready pcb, or make one with acid. My method is re-utilizing old pcb's, it works great.
I have no means of uploading pictures, as i have no camera. But, i will draw the layout i have made, and post it here.

Now, everything sounded right from the moment i pluged it in, and turned up the volume, the sound of the guitar was coming through fine without distortion, then i raised the distortion, it was okay until i reached about 10% of the distortion Pot.
Then, a weird noise started coming through, like motorboating, but a little high pitched.
As i continued increasing distortion, this noise reduced it's frequency, up to the point where it was just a few cracks far apart from each other. That occurs with the distortion at max.
Similar to what this guy describes as his problem, if not the exact same thing:
http://www.diystompboxes.com/smfforum/index.php?topic=103909.0

I tried the suggestions of R.G. there, with no success, checked every component he suggests, everything seems fine in the circuit.

Here are my voltages from the IC:

Battery: 8.96 v
Pins:
1: 7.72 v
2: 6.57 v
3: 6.03 v
4: 0
5: 0
6: 6.51 v
7: 8.48 v
8: 6.44 v

And the voltages with the distortion raised to max:
This is really weird, almost all voltages are negative.
Pins:
1: -0.35 v
2: -0.36 v
3: -0.23 v
4: 0
5: 0
6: -0.43 v
7: 0.01 v
8: -0.08 v

If anyone can shed a light in this matter, i'd be much appreciated.
Thanks in advance!
Sabudum.

[Sabudum]

Here's the layout i have made, dotted lines represent wires that run on top of the board.

http://www.mediafire.com/convkey/1856/z9yqonhzgou6xrhfg.jpg

Uhm, i forgot to add a few wires there, like the one that leaves the mosfet to that 1M resistor to ground.
And the one that leaves 0.0033 uF capacitor to ground as well, but they exist in real life.

[ashcat_lt]

I suspect that there are a number of issues here.  

The big one is that it appears your distortion pot is shorting out you power supply.  I can't see anything in the layout that would cause this.  Therefor it must be either wiring error or sloppy soldering or both.  First verify that all of the off-board and across-board wires actually go where they're supposed to.  Then go through (maybe with a magnifier) and check for accidental solder bridges.  When you find an error, don't stop and wonder if it could cause your symptoms.  Just fix it.  You could keep a catalog and report back so that we can all learn from it, but you need to fix it either way.

[duck_arse]

with power off, measure the resistance from pin 7 of the ic to the +9V at the top right of yr layout. does it vary as you work the distortion pot from high to low?

[Sabudum]

Indeed, resistance is 9 ohms at distortion min. And 0.05 ohms at distortion max.
So, that means the distortion pot is closing a contact that it shouldn't.

EDIT: And i forgot, so sorry, many thanks for your help guys, i still haven't found the issue, but i feel i'm close to it.

EDIT2: Also, i forgot to mention, and i am very dumb because of this, i couldn't find a 30 pF capacitor, so i used a 33 pF, and, i couldn't find a 0.0033 capacitor, so i used a 0.0022 capacitor, can this be so bad as to cause this symptoms?

[duck_arse]

the 33pF will make very little diff to the pedal. the .0022nF is the tone control, such as it is, and may start "tone-ing" a little high. you can add a .001/1nF cap across the .0022/2n2, and you will be close enough for jazz. or metal.

I think you should be reading 47R if you have your ic wired to the + supply right. try tracing from the bottom of the 47R resistor, and see just what it connects to.

[Sabudum]

yes of course, i accidentally measured something else, that's odd, i cant get that reading again anywhere near pin 7. Maybe the problem solved itself? Sorry, it is 47R indeed, with distortion at max, 47R as well.
the 47 resistor connects to a diode, 1n4002, one 100 uF cap, pin 7 of the ic, collector of the transistor J310, a 100K resistor, and a .01 cap.
Everything seems fine with this line, there are no solder bridges whatsoever.

EDIT: i'm redoing every solder, if this doesn't solve the issue, i'll consider changing some components.

[duck_arse]

can you post some photos of your work?

[Sabudum]

i dont have a camera, but i will try to borrow one from someone, hehe

[Sabudum]

Allright, i redid every solder, now the problem is reduced to almost nothing, but when distortion is raised to teh max, it becomes very muddy, the guitar sound is almost impossible to hear. but i guess it is just because of my guitar being a little cheap.

[duck_arse]

boy oh boy, are we dopes! your layout pic shows you have, from pin 2, the 47R connected to the 4u7, and the 560R connected to the 2u2 caps going to ground. swap these 2 caps with each other. AND, on pin 3, you have a ".01" shown on your layout, which should be ".001", 1nF/1000pF.

that is 3 reasons for mudd, so make those changes and if you aren't 100% then, remeasure yr voltages and post again.

[Sabudum]

Okay, i swaped those two capacitors, and the muddy sound got down a little bit, then i decided to change the .01 cap for a .001, and after i did this, guess what? That initial problem started again, only this time it is a lot worse! hahaha
The sound is so clean and beautiful with a low distortion, but when i raise it up past 15% or so, that crazy buzzing starts, and gets worse the higher the distortion is.
I just don't get it.

EDIT: okay, i just measured the 9v power supply i bought a few days ago, and it has 14v! even though it says 9v.
Question: can this voltage cause the effect i have been having with this pedal?

[ashcat_lt]

EDIT: okay, i just measured the 9v power supply i bought a few days ago, and it has 14v! even though it says 9v.
Question: can this voltage cause the effect i have been having with this pedal?

Nope.  It might explode any underspeced caps in the power supply, but that would probably cause other issues, and would be pretty obvious.  I had been running mine off of an adapter that reads 14V unloaded for a couple years, and had no problems with the Rat itself.

[duck_arse]

the power supply. the rating plate says dc, doesn't it? now, you have to waddle yourself over to amz:

http://www.muzique.com/lab/hum.htm

read that page. taking the circuit in the first diagram, you can increase your 47R (I think it was) in the +9V, to 470R, say, and the 100uF can be as big as you have, try 1000uF if you have it.

otherwise, search up a 9V regulator circuit, there are some about this forum. you only need a 78L09 and a couple of small electros, and it will clean up yr crappy supply real good.

[Sabudum]

Just went to the local electronics store complaining about this font, they gave my money back, so i bought a better supply at another store, this one reads 9v.
Still hasn't tested the pedal though.

EDIT: According to what i read on this article, Duck_arse (funny name btw), it seems my circuit is picking some kind of interference and amplifying it, cause, when i raise the distortion a little high the problem occurs, and with even higher distortion, the problem gets way worser.
So, maybe i'm getting some kind of electromagnetic radiation, like from fluorescent lighting, which i have.
Gonna do some heavy shielding, and test it.

[Sabudum]

ALLRIGHT! Found what the problem was, the 100pF capacitor at the distortion section was damaged, so it was leaking current, whatever that is. I replaced it with an older one i had, and it worked like a charm, the only remaining issue now is that the pedal makes a little crackles and pops. but that's okay.

Many thanks for the help of you all, guys, anything that i can help with this pedal, feel free to ask.

EDIT: I also get a loss of volume when using the pedal, and the distortion is a little dull and "liquid" in some way, at higher distortion i get an effect similar to a deep VOX amplifier.

Any ideas?

[duck_arse]

sounds like you've still got some work to do, but well done so far.

[Sabudum]

Thanks, i noticed that cheap ceramic capacitors tend to produce a lot of noise and clicks, i've replaced all ceramic capacitors with polyester ones, and, they are pretty much more efficient. And less noise making.

EDIT: I also noticed now that i accidentally used a 100000pF capacitor instead of a 100pF one, there is a code of 104 on it, but it is kinda blurred, so i mistook it with a 101 code, haha, replaced it, removed that VOX like effect.

[duck_arse]

yeah, 100nF would do that. so, it's all done now? when do we see it?

[Sabudum]

It's all done! sounds amazing. i'll be uploading some pics soon, as well as some sound samples, maybe a video. The casing is made with a sardine can, haha.