Let's Design and Build a (mostly) Digital Theremin!

Posted: 10/14/2024 8:13:57 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"Does a DAC connected to the digital output (Toslink or S/PDIF) produce a pseudo stereo line output or headphone and line outputs, Or is it selectable somehow?"  - André

The J10 expansion port is described on page 59 of the manual, here in HTML format from the support page of the D-Lev web site:

  https://d-lev.com/support/D-Lev_Manual_2024-01-08.html#__RefHeading___Toc10167_2833491093

The TOSLINK output data is for the MONITOR, and it is in stereo.  This is identical to the data output on pin 10 of J10, which is SPDIF.  If you want / need a separate stereo LINE out, you will find it on pin 12 of J10, also as SPDIF.  Their levels are controlled digitally by the LEVELS:Mon and LEVELS:Line knobs.

The MONITOR output has the pitch preview mixed in, and the LINE output doesn't, that's the only difference.  For the separate LINE out you'll need another DAC box.  Most folks seem fine with just the MONITOR out, as the LED tuner generally does the job of allowing one to come in on pitch.

For the PROZOR DAC boxes that come with the kit, the RCA line out and 1/8" headphone out are internally electrically connected together, which was a surprise to me.

Does that answer your questions?

Posted: 10/14/2024 8:49:36 PM
André

From: 30 km south of Paris (France)

Joined: 12/23/2022

Yes and ... maybe yes !

Technically, it's clear.
Still not quite understanding how to use the monitor output alone, and not have the audience hear it.
But may be I wont need the monitor and will only use the tuner.
I can only answer that when trying and playing the instrument.

Thanks for your patience with me. I have probably read only 10 % of the documentation and I discover something new everyday !

Posted: 10/15/2024 8:20:59 AM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"Still not quite understanding how to use the monitor output alone, and not have the audience hear it."  - André

Oh, sorry, I should have been more explicit about describing this use case.  To use pitch preview (PP) with the monitor output alone you would split the stereo MONITOR output between left and right via the PREVIEW:mode knob.  For its settings please refer to the table on page 20 of the manual or the last page of the quick reference guide:

  https://d-lev.com/support/D-Lev_Quick_Reference_2024-01-08.pdf

Modes 1, 5, and 9 split L & R, where L is for the audience and R is for player PP monitoring.  In these modes L will contain NO PP, and R will contain ONLY PP, so if the player wants to monitor both their playing and PP, they will need to somehow mix L & R externally (electrically or acoustically).  Mode 1 applies whatever pitch correction is being applied to the voice also to the PP pitch.  Mode 5 gives no pitch correction to the PP pitch.  Mode 9 applies hard quantization to the PP pitch.

In my mind, the "right" way to handle PP is to install a second LINE DAC (via SPDIF on J10) and use this exclusively for the audience, which then allows modes 2, 6, and 10 to mix the synth and PP on the D-Lev rather than externally.  It also allows for player stereo monitoring, which I feel is superior, particularly when reverb is being used.

There are some voices that use the PP oscillator as a 4th oscillator (modes 0, 4, and 8) or as DC stimulus (mode 12) for percussive ringing of bells and such.  This obviously rides roughshod over the whole concept of PP.

"But may be I wont need the monitor and will only use the tuner.  I can only answer that when trying and playing the instrument."

PP is there in analog instruments because players need something to help them come in on pitch, and it is a fairly trivial thing to implement.  I personally find the constant wheedling of PP in my ear very distracting, though you can set it so that it does "ducking" (only plays during voice silence).

I only know of two players who use the pitch preview feature: Roger Hess and Rob Schwimmer.  I don't believe Roger uses it full time, and Rob only uses it in rare situations where he is improvising on the fly in louder band type settings.  I believe most find the tuner adequate for the task, and I of course watch it like a hawk 100% of the time during play.

But, yes, give it a go as-is and see what you think, and give yourself room to experiment.  It seems that many crucial aspects of musical instruments can't be known purely by thinking about them before the fact.

Posted: 10/15/2024 4:38:43 PM
André

From: 30 km south of Paris (France)

Joined: 12/23/2022

Thanks a lot, dewster. This is perfectly clear now.
You even answer questions that I didn't think of yet !

Posted: 10/15/2024 6:32:31 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

My pleasure André!  I like to do quick calibration video chats with new users to get their fields right, let me know if you are interested in that when the time comes.

Posted: 10/15/2024 6:51:36 PM
André

From: 30 km south of Paris (France)

Joined: 12/23/2022

I will certainly be interested! And it will be a pleasure to meet you in virtual reality!

Posted: 10/19/2024 2:31:20 PM
André

From: 30 km south of Paris (France)

Joined: 12/23/2022

Work in progress ! You will recognize your design !

Posted: 10/19/2024 2:33:44 PM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

"Work in progress ! You will recognize your design !"  - André

Lookin' good André!  Godspeed!

Posted: 10/23/2024 11:17:05 AM
dewster

From: Northern NJ, USA

Joined: 2/17/2012

UV Dope?

On the subject of coils: While ordering a deep UV (365nm) flashlight (https://www.amazon.com/dp/B0CMHYCQH4?th=1) as one does, it got me thinking about UV activated nail polish as coil dope - maybe eliminate the noxious fumes and get a quicker cure?  Which then led me to UV activated resin (https://www.amazon.com/dp/B0C49JNV4D).  I mean, you get more of the stuff for very little money compared to nail polish.  Both arrived last week and I tried some resin on an existing coil.  The resin would cure by itself on a piece of paper, but it never really cured on the coil, even after setting it in the sun for an afternoon.  Not sure what's going on, but it seems like a bust.

I saw a project on the web where they used lacquer thinner to dissolve Styrofoam, I'll probably try that route next.  At least that way I'll sorta know what chemicals and whatnot end up on my coils, increasing the self-C and such.

[EDIT] Got some lacquer thinner today, it makes Styrofoam soft and squishy, but doesn't entirely dissolve it.  MEK or the alternative seems necessary, but they only sell it in gallon cans nearby, and I only need a pint or so.

Posted: 10/25/2024 3:31:23 PM
André

From: 30 km south of Paris (France)

Joined: 12/23/2022

Dewster, be careful. Polystyrene + solvent : this is the recipe of napalm !
Don't use it next to your soldering iron.

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