DOD 440 EF Clone Project Questions

[thedefog]

I'm almost complete with my DOD 440 Clone (minus the wrong size power adaptor and wrong type pots sent that I'm waiting on).

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=138&Itemid=153

The pedal does work... only it distorts when it gets to the peak frequencies. I guess the best way to describe it is it sounds like an overdrive on the high end. This only occurs when the pedal is engaged and both knobs are turned up almost all the way to the right (where they kinda need to be to get the effect to work properly).  I'm using a humbucker pickup. I have an original DOD 460 mini-chorus, and I noticed that the humbucker causes an issue when strummed too hard (makes farting noises).  When I switch pickups (to single coil), i have the same problem, yet it is not as noticable.

I'm trying to debug this. I know it's not the chip, because I swapped it with an identical and got the same thing. My guess is 1 of 5 things. Let me know if any of these sound familiar:

1- the wrong type pot i am currently using to test the pedal is causing distortion (on/off switching 100k audio taper instead of regular 100k audio) - highly doubt it.

2 - my VTL5C4/2 Dual Opto Resistor is screwy, possibly from overheating and need to replace it with a new one - also doubt this. seems like this would simply not work at all instead of half-work. It's an LED... Should just blow. Right?

3- my silicon switching diodes aren't working properly. - I am guessing  that when these blow , they still allow current to flow though, acting like a jumper instead. Am I right about this??

4 - my 3pdt switch that came from a prior pedal project and had to be desoldered didn't survive the desoldering process. - more likely, yet makes no sense because in bypass mode it works fine.

5- i'm retarded and just have it wired wrong/wrong value parts,  even though i've looked over it a dozen times and poked at it with the multimeter.

would the regular carbon resistors used over metalic type cause a distorted sound? I'm using the grab-bag radioshack crapresistors. 1/4 watt type.

also, i was missing a 1uf polarized cap from my parts, so i ganked it out of an old (yet functioning) intercom unit.  perhaps???

I've tried to narrow it down the best that I could. It's not the guitar/amp/chords/etc. I know this for a fact. It only happens when the pedal is engaged, and only at the peak of the envelope.

thanks,

-chuck

:?: