WARP633 troubleshooting

aerogramma

hello everyone,
time to swallow my newbie pride and ask for help Wink

I've built a papareill Warp633

http://m.bareille.free.fr/modular1/warp633/warp633.htm

but it doesn't seem to work properly, as someone reported before it doesn't really ring modulate, seems infact that is working only halfway

i've triple checked everything [yes i know we all say that Very Happy

] and still can't find the problem i'm posting a couple of picture and a sample of the module

in the audio sample i have fed a:

Moog VCO > into the Y input
and a LFO > into the X Input

Mix pot goes from Zero to All Wet

Then I use the DPDT toggle to switch between Divide/RingMod [you can hear the LFO clicking and the VCO very low in the background]

X pot goes full on
Y pot goes full on

not exactly sure what goes on!

on a side note i've used TL072 as op amps and three slightly different caps for the same value 1 mylar, 1 poly 63V, 1 poly100v [see pic]... no idea if that makes any difference

If anyone would be so kind to spare their time and give me their advice on what could be wrong it'd be very appreciated!

thanks

Wink

aero

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guitarfool · Posted: Tue Oct 21, 2008 5:58 am Post subject:

Sounds like it's working okay to me. It won't sound the way I think you're expecting unless you feed it 2 audio sources (another VCO in place of the LFO Very Happy

There's also the Z input on the Warp633 to play with as well, but the classic ring (or balanced) modulator is a 4-quadrant multiplier. A VCA is a 2-quadrant multiplier. What this means is that in a ring modulator, the sign (+/-) of both input signals is preserved (4 quadrants). In a VCA, on one of them (the control input) only the + regime is preserved (negative control is ignored). You can use a ring modulator as a VCA, its just that when the "control" voltage goes negative, the output will invert, but to the ear this is not very noticeable.

aerogramma · Posted: Tue Oct 21, 2008 6:07 am Post subject:

hello guitarfool thanks!
the overall concept explanation is very useful cheers

I was comparing my results with the ones on papareill webbie where it seemed to me he was getting a lot of klang with an LFO + VCO combo, but probably i'm mistaken Smile

I'll try again putting different VCO into the X and Y inputs and post a result
[i've got Z pots implemented too]

Wink

aero

aerogramma · Posted: Wed Oct 22, 2008 9:24 am Post subject:

Ok i've run some tests and i'm still not convinced it works properly Shocked

i've have been using RM for a long time i have a moogerfooger RM here and this just doesn't sound like a RM...

I've also take some measurments, the weirdest (to my untrained brain) was the Y mix pot which albeit being 100k would read only 0-20k with the board on the bench disconnected. I have of course tried to change all parts involved but still same results.

I've got 2 new lovely samples for you * don't hear them through your headphones as waveshaping ca be harsh! *

sample guitar test - I've tried to do a tremolo guitar with
Y input: guitar
X input: lfo

going from dry to 100%wet and switching between RM and Divide

fiddling with the Y pot with almost no audible result

very little success

sample moog guitar test -
Y input: guitar
X input: moog vco

going from dry to 100%wet and switching between RM and Divide

fiddling with the Y pot with almost no audible result

wonderful waveshaper yes, RM not quite Wink

I'm starting to think there's something wrong with the board..perhaps?

sorry for the long post!

aero

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guitarfool · Posted: Wed Oct 22, 2008 6:29 pm Post subject:

You may have it wired up incorrectly - hard to say.

This is designed to be a synth module, and as such expects inputs to be in the +/- 5v (10v p-p) range. Same for the output. The Moogerfooger is an effects pedal, so I presume it has it's own built-in modulation oscillator and a preamp for the instrument input. To use the Warp with an instrument, you need to boost the input by probably a factor of 20 or more. Ken Stone has a nice schematic (and PCB) for using synth modules as effects and vice-versa. You also need an oscillator to feed it and audio range modulation to do classic ring-mod type stuff. The rule of thumb for the output is that the tones will be the frequency sum and the frequency differences of the 2 inputs.

Oh, I forgot to mention earlier Embarassed

the 633 also needs something for the "z" input. I added the 633 chip output (through a trimmer) normalled to the z input on mine. You can see details here: http://www.guitarfool.com/modules/Warp633.html

aerogramma · Posted: Wed Oct 22, 2008 11:38 pm Post subject:

thanks again guitarfool!

Sure that was one of my first thoughts, but it's not like a klee sequencer, you can only wire it up wrong a definite number of times Wink

and after careful double checking i can exclude the wrong wiring scenario Smile

you are absolutely right about the moogerfooger but the test i tried with the guitar is the same on papareill webbie
http://m.bareille.free.fr/modular1/warp633/warp633.htm

DI guitar + lfo (lfo coming form one of fonik's modules)

and if the module is working properly the test should have produced good results, no? Shocked

next , following your advice about the 'z' input

Wink

aero