Yusynth VCO range selector

[rubdrisi]

I have designed PCBs for Yusynth VCA, noise generator, ADSR envelope, and Moog filter clone. While preparing to design my PCB from the oscillator schematic I realized there is not a range selector. Any info on how I can add a range selector mod to this VCO?

Also, if an oscillator does not have a gate for note-on/note-off, how can it produce a C note with value 0V?

The page at Yusynth with the schematics is at
http://yusynth.net/Modular/index_en.html

Direct link to the image file is http://yusynth.net/Modular/Commun/VCO/VCO-sch-thumb.gif

Ru Drisi
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[magman]

Hi Ru,

First, welcome to the forums.

There is actually a dedicated forum here for supporting YuSynth projects, here: http://electro-music.com/forum/forum-170.html. It might be worth asking one of the mods to move your question over to this forum as you will be more likely to get additional replies.

I will attempt to answer some of your question now though.

First, most VCO's are not gated at all, they continually produce a tone. It is the job of VCA's, normally controlled by an ADSR to control the amplitude (or volume) of the tone that is generated by the VCO.

Next, the tuning of the oscillator is accomplished by the coarse and fine tune controls. You set the initial note that the oscillator plays with these controls, say a C at 0V on CV input, then each 1V increase on the CV input will raise the note played by the oscillator by 1 octave.

These controls work by feeding a voltage into the oscillator CV control circuit, so If you wish, you can replace the coarse control with a switch with selected resistors to give you the range steps you are looking for. The pot used for the coarse control is a 25k, so a switch with 10 by 2K5 resistors would be a basic solution. A better solution would have trimmer resistors at each end of the divider resistors, so that you can get an octave change for each switch step. There have been a few designs for this kind of switch (Called an Octave Switch) posted on these forums in the past, try the search tool on the forums to hunt these down I f you still want to go the switched route.

Personally, I have used the YuSynth Standards module to do a similar function, for a few of my VCO's, but mainly to set a fixed offset when using multiple oscillators (one VCO tuned a precise note different from another VCO). For normal operation though, I just tune the VCO's using the normal coarse and fine controls then rely on the keyboard or sequencer to provide the CV control.

Hope this helps

Regards

Magman

[Blue Hell]

Ah .. had missed it, thanks for pointing that out magman - moved now.

And welcome Ru.

[yusynth]

Hi Ru

If you read thoroughly the VCO page down to the "The DIY builder's gallery" you will find a link to a PDF giving information to add an octave switch :

[rubdrisi]

I don't know (yet) how to make a reply that is to a specific post. Here goes; we'll see what happens with this one.

Thank you Magman and Jan. I think this forum is very special. A very special thank you and props to Yves. I hate it when I miss something in the instructions. I still baffle myself on how I do that.

Ru Drisi

[Blue Hell]

[rubdrisi]

Glad you like it and please don't be afraid to make mistakes we'll find a way to fix it if you mess up .. it's the only proper way to learn after all [/quote]

Thanks, Jan.

[rubdrisi]