Please help me get my envelope filter working!

[shawsofhell]

Just finished the MXR Envelope Filter using the tonepad layout and I did it with all the mods. Unfortunately it doesn't work. What I do get is when I play a note the unit goes silent for the initial attack then makes a popping noise as the sound comes back when the note gets quieter. I have checked all my IC orientations and the wiring of the off board components but haven't found anything wrong. Another thing I noticed was when I turn on the reverse sweep the unit goes comletely quiet. Could this mean there is something wrong with IC1? The ICs I used have the following markings CD4066BE and CD4069UBE is asume these will work as I have heard some people say that some ICs will not work with this circuit.
Thanks for any suggestions!

Here is the schematic:
http://www.tonepad.com/getFile.asp?id=5

[shawsofhell]

how can i test the ics to see if they are working? how sensitive are these ics to being touched, as i think you can kill some with the static from your fingers?

[gez]

What I do get is when I play a note the unit goes silent for the initial attack then makes a popping noise as the sound comes back when the note gets quieter

Sounds like it's oversensitive and the PWM is cutting the signal off.  Do matters improve if you turn down the sensitivity knob (don't have a schematic in front of me, but there should be something to adjust sensitivity).

I don't have any experience de-bugging one of these, but posting a link to the schematic always helps (others might chime in).  

[Mark Hammer]

Notwithstanding the usual sorts of boneheaded construction errors that invariably creep in (and that ALL of us commit), some people have reported initial difficulties that went away when they switched from one brand/manufacturer of chips to another.  This effect is entirely separate from the issue of using buffered vs unbuffered.  I'm not sure how it occurs, but I have to take them at their word.

So, who manufactured the CMOS chips you are using?

[shawsofhell]

are you able to tell from the chip who manufactured them? the only info I have is a data sheet attached to the web site I bought them from which would suggest their made by Fairchild the only thing is this data sheet is for a 4066BC and mine is a 4066BE and the the other data sheet is for a 4069UBC and mine is a 4069UBE. Are there any differences?

[niftydog]

the only info I have is a data sheet attached to the web site I bought them from which would suggest their made by Fairchild

unfortunately that means nothing... but you have all the info you need right there on the chip. Have a close look to see if you can find a logo, see here to cross reference a manufacturer.

Sometimes, the prefix tells you the manufacturer. Could you tell us ALL of the markings on the chips?

4066BC, 4066BE, 4069UBC, 4069UBE

The BC ones are either national or fairchild . The BE ones are most likely Texas Instruments (TI) Probably all with a CD prefix?

The C and the E are the different manufacturers way of designating the package type (ie; 14 pin DIL)

If you're really interested, get back to me with ALL of the markings on the chips.

[shawsofhell]

It looks like it has the texas instruments logo on it. Have other people had sucess using this chip before in this circuit?

[Gringo]

I built mine with all TI chips, and it worked, but it didn't wha. I replaced IC2 with another brand's ic and voila!

Others reported they had to change all the chips to non-TI brands.

Good Luck!

[shawsofhell]

ok so i'll try changing my chips and pray!

I have already chnaged some output caps and resisters to get rid of the volume drop and tone sucking that alot of people mention, any other suggestions to get this thing working at its best?