PLEASE, HELP ME WITH MXR ENVELOPE FILTER

[giba_g3]

I have problems with MXR ENVELOPE FILTER.
When the unit is on it does not work well, and it didn't wha.
I debuged many times and everything is OK, except the values of 0.05 caps.
I'm using 0.047 uF.

When the unit is OFF the bypass is OK.
The OffBoard Wiring is OK too and I'm using Millenium Bypass 2 from GEO.
What is wrong ??
The Ic's are Philips(4066) and Toshiba(4069)  
The diagram is here http://www.tonepad.com/getFile.asp?id=5
Please help me !!
Thanks  

[markr04]

I highly suggest you do the Emphasis mod. Some of them won't wah without it. Read the build reports on the Tonepad site. They're very valuable, and I wish other sites had such a feature.

Is it just low-pass filtering, not opening up? If so, are you using a single coil pickup by chance? Those are tough to make it wah. If you have a HB guitar, try it instead. Try sticking a booster in front also.

I'm using RCA and Goldstar ICs. Yours should be fine too.

[Mark Hammer]

The Empasis mod will make little difference in whether it works or not....unless you do it wrong.

In fact, different issues of the EF had different resistance values in that loop the Emphasis mod turned into a variable control.  I always wondered why one of the EFs I owned sounded better than the other to my ears.  It would appear that later issues upped the resistance value in that feedback loop and increased the resonance/emphasis, giving it a more robust sound.

There are a few possible problems with your build, Giba.

One is that you simply aren't giving it a strong enough signal.  Try sticking a booster stage of some kind (fuzz, compressor, preamp, etc.) between the guitar and EF and see if that makes a difference.  A second reason is that the 4066 and 4069s you are using are the "wrong" ones.  Several people have noted that the pedal worked much better for them when they changed from one brand to another.  I just stumbled onto a picture of the board from one I owned way back when they first came out.  It used an RCA chip - CD4069UBE and CD4066UBE.

The difference between .047 and .05 caps will make not any difference at all.  The original caps were almost all cheap ceramics, which have very wide tolerances.  I doubt whether ANY oof them actually measured .05uf!

[StephenGiles]

Mark, you have taken the words right out of my mouth! I would also put my money on a solder bridge somewhere if he is 100% sure that all the component placings are correct. Do you know I still havn't soldered one of these up, I have the parts in a little bag which has travelled to the West Country and back twice on holiday without being made.
Stephen