PlanetZ forums - scopeusers.com

Hi,

A Pc1600x has 2 analog inputs, a CV and one switcheable CV/footswitch. What can I connect to them?

I know the switch, it's a pedal that acts as on/off. Can I connect analog outputs from synths or Luna2496 to a CV input and use them to mudulate stuff? Or will it burn the outputs from the synth or Luna2496?
Before I try, I'd like to read some suggestions...

Cheers!

Boldly going where no man has gone

I dunno At0mic, Control voltage is a lot more than Audio signal. Correct me if I'm wrong but isn't CV around 5volt, I doubt an audio signal would do anything unless you crank the s#t out of it and that may open a whole set of other problems.

Davo

I have both the PC-1600 (2) and Doepfer Drehbank (8 CV-inputs) and currently I use those inputs to convert things like my analogue sequencer output, analogue synth LFO's etc to MIDI controller or note data.
In the past I've connected audio-sources to the inputs and there *did* appear some modulation of the MIDI-controller although the result wasn't exactly like an envelope follower (which would be cool!:) )

I think 2 things are to be considered:
- an audio signal is AC, thus passing the 0-V axis every now and then (negative voltage causes a sampling of value "zero")
- the sampling rate of the Peavey or Doepfer is very low compared to the frequency of the audio signal.

Don't know much about electronics (yet), but I thought about making a simple diode bridge rectifier to have the wave rectified (stay above 0V). But first I have to amplify the audio signal to a 5 V range (a cheap radio amplifier will do, I guess) to use the full sampling depth of the Peavey and get beyond the 0,6V minimal voltage for the diodes. (Right?? Any electronicians here? )

And then maybe add a small RC filter to even out the frequency contents a bit for easier sampling by the Peavey.

I hope this will me an envelope follower, but I'm hardly sure.....

Okay, thanks guys!

The rectified signal should be no problem, I think it can be done in Modular. And DC can be sent from the analog outs on CW cards. I'm sure rectification can be done w electronics too, but Modular makes it more simple. (for example using an ADSR)

Guess I'll need that pre-amp though, to get from .5 to 5V. Anyone knows how I can fix one? Or knows a page that explains how to make a mini analog amp? Sound quality is obviously not important, and it'll convert .5V DC to 5V DC.
But 5V, isn't that S/P-DIF operating range? Anyone been so experimental to output via S/P-DIF out? What resistance is to be on the CV? This may be interesting!

Btw, yesterday I experimented with this. It is getting more and more fun this Pc1600x! Probably this Doepfer-type sequencer can be emulated on other remote devices too!

More CV fun w Pc1600x may be a fun read too. Ernest, is this yours?

I think it's possible to have the modular throw out some interesting waveforms for the Peavey to sample... but it depends on the D/A and amplification used whether the signal will be rectified in the end.
I've taken the low-fi shortcut and threw some brute-force audio into the PC1600 in the past (taken from the speaker-out connector on a 2 x 12W ghetto blaster, which is a nice sources for noises anyway) and tweaked the volume and EQ until I somehow got full CV-range modulation. No rectification or other electronic wizardry, but the results turned out to be almost random modulation (wich was interesting enough, of course ) And the good thing: the PC-1600 survived the torture!!! Also some of my analogue stuff throws out +/-10V and still no smoke from the Peavey... your mileage may vary of course

I don't think the s/pdif-out will be give much pleasure for this purpose... the specs state 0.5-1.0V for s/pdif (although some CD-ROM-drives and soundcards give a whoppy 5Vpp) and 3-10V for AES/EBU.... But more important: the frequency of this 2-state signal is over 2 Megaherz! Peavey nor Doepfer will be able to sample it
This document gives a pretty good description of s/pdif and AES/EBU standards.

And thanks for pointing me to the More CV fun w Pc1600x-link.... Potverdriedubbeltjes, that asshole stole my name!!! Those dutchmen have no respect......

If you are going to rectify the input signal you will need to boost it and then attenuate it aftewards, or else use a precision rectifier chip. if you just use diodes it will not be very good because they do not work below 0.6 volts.

I know it won't sound hifi.... nevertheless it will sound, errr, interesting I know a person who made such a crude diode-based amplified rectifier-device and it sounded like a frequency-doubler with a ringmodulator-kind-of vibe...