No "Phunc-Down" on my Phuncgnosis; Any ideas why?

Started by hillio, December 24, 2007, 01:35:49 AM

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hillio

I breadboarded a Phuncgnosis today, and it sounds good except for the down sweep, and the loud pop when switching between up and down.  I've read all the previous posts on this board pertaining to both problems, but haven't been able to fix either of them.  I prefer the sound from the 'down' side of the filter, so I would like to get it working if possible.
As I said, the up side seems to be working OK, although the sensitivity pot has to be turned up pretty high for good sound.  When I switch to the down side I get the loud pop that lots of others have complained about, and I get no noticeable 'wah' effects along with reduced volume.  I have tried every different color and type of LED you can think of, with no effect on the down side.  Red or yellow seem to work best on the up side.  I have tinkered with caps and resistor values, which only served to make the up side sound worse, so I'm back to the values posted on the schematic. I've tried three different TL082's and they all sound the same.  I'll get some different op amps when I get the chance, but from what I've read, the 82's should work well for this circuit.  I tested the voltage on all the IC pins, and they are as follows:

1: 4.52
2: 4.52
3: 2.04
4: 0.00
5: 4.49
6: 5.51
7: 5.51
8: 9.0

Pin 6 is U1B - (Non-inverting) input. Should it be seeing full Vr? 
The down side LED's all light very dimly when switched on, and I can see them fade out and back in when a string is plucked, and they respond to the sensitivity/depth/volume pot, but the sound output doesn't follow suit, or so it seems.
As far as the switch 'pop' goes, I tried the 47K resistor from pin 7 to ground trick, but it had no effect whatsoever.

There's where things stand right now, so any and all suggestions will be greatly appreciated.

Thanks.

***I forgot to add that I am using a Switch Stealth guitar with dual humbuckers, if that makes any difference.


hillio

Sorry for yet another post, but the modify option wasn't available anymore.....

The voltage on pins 6 and 7 was actually 4.51, not 5.51 that I listed before.

Just wanted to clear that up.

Thanks

raulgrell

IIRC, the phuncgnosis is known to have a much better up sweep than down sweep... Try putting a few transistors where the led's are... I'd try it out myself, but I'm lacking in equipment at the moment...

Some logic in case I sound insane  ;D Trannies are basically diodes in a special arrangement... So if diodes are meant to have an effect, transistors, properly put together, should as well. Be creative is all I can say, to be honest I have no idea what I'm talking about...