Anushri LFO/envelope CV out mod

Hey Anushriers -

I came up with a very simple mod that allows sending the anushris LFO or mod envelope to a cv output, and thought I’d share it.

The topic has come up before http://mutable-instruments.net/forum/discussion/3085/lfo-and-envelope-cv-outputs-on-the-anushri/p1
And indeed, creating dedicated lfo/adsr outs would be pretty tricky. But what can be done instead is to piggy back off of an existing mod “target” within the anushri, and to steal it’s mod source. I chose pulse width, as it seemed the least critical. Here’s what you do:

1) Remove R28 (which mixes DAC_PW with PW CV IN)
2) Add an output jack to DAC_PW… and ground of course ( I used the “audio in” jack on my anushri euro expander… there’s already an in on the main faceplate, no need for two, and this way, no need to drill any new holes etc ).
Done!

Now the “PW MOD” knob functions as more of a “mod output select/depth” knob. Send that LFO to VCA in for tremolo effects. Send the EG to an inverter and back to anushri for reverse envelopes. Turn LFO Shape to noise and send noise to audio in to be mixed into the synth voice. Not to mention the endless possibiities for using anushri as a source of cv to control other stuff.

The downside: There is no longer a normalled connection that allows for PW modulation without patching your new output into the PW CV IN… but hey, that’s what that PW CV IN is for, and with just a little extra work, you could use a jack with a make/break connection and keep DAC_PW normalled to control pulse width when the jack is not in use.

Limitations: Obviously this doesn’t allow for simultaneous use of LFO and EG cv outs. Also, it uses the mod EG which is only Attack/Decay. I’m going to explore to see if there’s any opportunities to update the firmware such that the ADSR envelope will be sent to DAC_PW out. If anyone has insight there, please share!

One tiny practical question: I’m sending DAC_PW straight to the output. It works great as is, but in general should I add an output resistor or diode or buffer amp or anything like that between DAC_PW and the output? To protect/buffer the DAC from the outside world? I notice there’s buffers between DAC_PITCH and DAC_CUTOFF and their respective CV outs. Is that just to ensure that external use of those CV signals don’t interfere with their internal behavior?

The end!

> Is that just to ensure that external use of those CV signals don’t interfere with their internal behavior?

These are not buffers, these are amplifiers. Anushri runs internally at 0.5V/Octave (because it’s only +/- 5V powered) so this scales the output CVs up to 1V/Octave.

For the DAC_PW output, you can have the same circuit to double its range. At the very least, you can have a small-ish series resistor (between 100 ohm and 1k) to protect the DAC in case the user patches by mistake another output into this output.