Phuncgnosis Ideas...

[jishnudg]

So I've been working on the deadastronauts modded Phuncgnosis (schematic here  http://www.diystompboxes.com/smfforum/index.php?topic=49246.0   ) lately,trying to tweak it a bit...had a few ideas for mods which haven't made it to the breadboard yet,so I thought I'd get some suggestions here -

1. Insert a 5k Trimpot right after the 2.2uF cap to ground (that comes after the 'super bright green LED' in deadastronauts schematic), and replace the 1M pot with a trimpot to set a constant attack and decay. Would 5k be a good value for a trimpot or should I use a larger/smaller value?

2. Replace the 330k resistor with a trimpot to set a constant range.

3. Put the 1M sensitivity pot back into the circuit (at the input stage) and put a stereo switchable jack with which I could plug in a volume pedal and use the wah as an autowah if desired. Has anyone tried using other values (470k,220k,100k) for the sensitivity pot?

4. Have a buffer preceding the effect which splits the signal, and adding a blend control at the end of the circuit. What buffer would work best with this circuit? I've read good things about the Cornish buffer and Klon buffer; would they work here? Also, should I make any modifications to the input stage to accommodate the buffer better?

5. Using two parallel autowahs with blend control at the end,using a quad opamp (TL074 etc)...has anyone tried this?

Thanks and regards,
J.

[pinkjimiphoton]

So I've been working on the deadastronauts modded Phuncgnosis (schematic here  http://www.diystompboxes.com/smfforum/index.php?topic=49246.0   ) lately,trying to tweak it a bit...had a few ideas for mods which haven't made it to the breadboard yet,so I thought I'd get some suggestions here -

1. Insert a 5k Trimpot right after the 2.2uF cap to ground (that comes after the 'super bright green LED' in deadastronauts schematic), and replace the 1M pot with a trimpot to set a constant attack and decay. Would 5k be a good value for a trimpot or should I use a larger/smaller value?

you want the 1m pot to be adjustible. up and down modes require different setting to get the best effect IMHO. that said, if replacing a 1 meg pot, you'd want a 1 meg trimmer, not a 5k one.

2. Replace the 330k resistor with a trimpot to set a constant range.

maybe. you could try it, but why would you want a constant range on an envelope device? seems counterintuitive... don't succumb to BUTM syndrome...get it working first and rock it before ya box it.. try the mods on your breadboard. imho, having built a few of these, more control is a good thing for fine tuning.

3. Put the 1M sensitivity pot back into the circuit (at the input stage) and put a stereo switchable jack with which I could plug in a volume pedal and use the wah as an autowah if desired. Has anyone tried using other values (470k,220k,100k) for the sensitivity pot?

it IS an autowah pretty much. sweeping the sensitivity with a volume pedal probably won't work the way i think you're expecting. all that does is set the threshold for the circuit to trigger.

4. Have a buffer preceding the effect which splits the signal, and adding a blend control at the end of the circuit. What buffer would work best with this circuit? I've read good things about the Cornish buffer and Klon buffer; would they work here? Also, should I make any modifications to the input stage to accommodate the buffer better?

dude...you add a buffer to the input, and it's gonna completely change the way it works. it needs to detect the envelope of the circuit's dynamics, a buffer will stop the interaction of guitar dynamics and the input of the effect. even putting a fuzz in front of it messes with it quite a bit. an output buffer may be a better idea. try putting a buffered (say, a boss) pedal before it and see what happens. it may work, or it may not. in my experience, these things need to be real early in the effects chain, and before any buffered anything for best tracking.

5. Using two parallel autowahs with blend control at the end,using a quad opamp (TL074 etc)...has anyone tried this?

that's sort like an electro harmonics bassballs circuit. the tl074 may work, i don't see why it wouldn't. you may wanna investigate the eh talking pedal and colorsound vocalizer threads.

two parallel autowahs can be VERY hip. if you tune them to different ranges, you can get some awesome effects out of 'em. i doubt you'd need a blend control, as the envelope going in is gonna be the same hitting both filters.  try it out, see what ya get, and please, let us know how your experiments go!

Thanks and regards,
J.

rock on, j.. these are only my opinions, YMMV

[deadastronaut]

^ i concur...

mods:  you can change the freq of the filter by swapping the 2x1nf's....in the original they were 680pf's IIRC...

i was using it combined with a fuzz, and prefered the 1nfs...

glad to see someone else breadboarding this...

[jishnudg]

Thanks, guys...so I looked into your suggestions, and came up with this -

https://docs.google.com/open?id=0BwMVia471c4SQXFLdzhWRnFSeWc

(sorry for the messy circuit; its the first one I've drawn from scratch)

Its pretty much a hack of deadastronauts modded schematic and a schematic of the Klon buffer I found on the net; using both these designs as building blocks.

The concept is that the input buffer splits the signal into three, one clean, and two going into different envelope filters.
Both filters are loaded with potentiometers which are supposed to all be trimpots (only the final 'blend' pots for clean/wah and wah/wah will be fitted with knobs), the idea being that the two parallel filters will be pre-set (using the trimpots) to sound as different from each other as possible - two opposing sides of the auto-filter spectrum,one could say, and the pot that blends between them at the end of the circuit could be labelled something like 'character'...so instead of bothering with attack,decay,freq,range pots, one could just dial in the perfect auto wah from this 'character' knob, and set the amount of clean blend with the 'blend' pot that follows right after (maybe a master volume could be crammed in too).

I've kept only one 'sweep' type cause I wont be fiddling with that much, but thanks to deadastronauts original mods to the phuncgnosis,to put in the alternative sweep would only cost me a switch and a daughterboard so I'm letting it be for now.

Hoping that the schematic doesn't have too many errors (am sure it will, its my first attempt at modding a circuit,so apologies for any mistakes I may have made).

So here goes...
1) how can the two circuits be made to sound as different as possible...I've already made provisions for the 1n caps, and attack/decay and range (atleast, I think I have)...are there any other parameters that can be tweaked?
2) has anyone tried using Joes Diode Compression Opamp circuit for the opamp stages? I figured that substituting the TL072s with the Diode comp. opamps would give me even more tweakability..would it?
3) how would the envelope filter interact with the buffer stage? what changes should I make to the input to accommodate the buffer (cause I'm pretty sure I want a buffer there, to split the signal)
4) any other suggestions/corrections?

Thanks again,
J.

[jishnudg]

Here's an updated and corrected version, using the AMZ JFET Buffer/splitter at the input, and Davissons diode compression opamps to replace the TL072. Will this work?
I've also crammed in the AMZ tone control at the end of the circuit.

Link -

https://docs.google.com/open?id=0BwMVia471c4SX19zb09OMXdSdGs

[pinkjimiphoton]

worth a shot...bread board it up, and see what happens!

really hard to see , at least for me. any way you could lay it out landscape style instead of letter style?
could make it easier to read.

cool idea!