MU single width VCO Ideas

7thDanSound · Post by **7thDanSound** » Thu Dec 23, 2010 3:24 am

And is it hard/expensive to make the CV in amount knob bipolar? That'd make it easy to invert things like envelopes e.g. when syncing.

essex sound lab · Post by **essex sound lab** » Thu Dec 23, 2010 9:49 am

7thDanSound wrote: Having a buffered CV thru might be nice however but it could be on the PCB instead. That way one could chain a couple of VCOs behind the panels. The 1V/oct jack on the panel could be breaking the connection.

Yes, this would be quite nice. One of the nifty things about a 1U VCO, to me, is being able to chain up a few to use as a bank. The behind the panel chaining would be great.

dslocum · Post by **dslocum** » Fri Dec 24, 2010 1:14 pm

OK. Input buffering sound like a cool thing. Thought I might also incorporate Oakley's CV/Gate buss as it's such a cool idea. Does anyone have experience with it?

Are the rear interconnect cables daisy chained when connecting more than one "slave"?

How does the "master" VCO supply this chain?
Maybe my thinking is wrong here. Could use some help.

I also wonder if it's worth a couple extra bucks to make the VCO compatible with Roger / Brian B's triple Soft Sync module?

darwingrosse · Post by **darwingrosse** » Fri Dec 24, 2010 2:46 pm

dslocum wrote:OK. Input buffering sound like a cool thing. Thought I might also incorporate Oakley's CV/Gate buss as it's such a cool idea. Does anyone have experience with it?

Are the rear interconnect cables daisy chained when connecting more than one "slave"?

How does the "master" VCO supply this chain?
Maybe my thinking is wrong here. Could use some help.

I also wonder if it's worth a couple extra bucks to make the VCO compatible with Roger / Brian B's triple Soft Sync module?

My suggestion would be to not add too many things, else it becomes a frankenmodule. For example, those of us that make more "sound" than "music" wouldn't find the daisy chaining all that useful.

(And here's where I contradict myself:) Sine output, on the other hand, does have a lot of value for FM purposes...

In any case, get rockin'! I need to get a bunch of 'em, and assuming the price is somewhere in line with your other stuff, it's going to be a big relief to grab these.

Just me · Post by **Just me** » Fri Dec 24, 2010 4:13 pm

Yeah, for me, no sine makes it a pass. I only want something like that for FM modulation. But, you will NEVER be able to please everyone. (But it could mean a market for more than one VERSION of 1U OSC.

dslocum · Post by **dslocum** » Fri Dec 24, 2010 4:50 pm

Would you give up TRI for SINE, or have it a jumper option?

Frankly, I -slightly- prefer a SINE over a TRI, given the option. However, I'd make the SINE like Rogers diode based sine - not as good as a finely trimmed LM13700 SINE. If you like Roger's SINE, then I can do that. If you REALLY mean _clean_ 13700 style SINE, it won't be in this module.

I DO apprecaite everyones input, and I'm trying my best to make the right musical vs price desicions.

dslocum · Post by **dslocum** » Fri Dec 24, 2010 4:54 pm

I like the idea of a -1 Sub-octave output in place of the THRU input. It's another chip, but as darwingrosse points out, I'm getting close to a FrankenModule - "Not that there's anything wrong with that!" (Seinfeld)

Any other ideas for the currently open space of the THRU jack?

dslocum · Post by **dslocum** » Fri Dec 24, 2010 5:12 pm

Oh yeah... OCTAVE SWITCHES....

The octave switch is more expensive for the panel space, the switch, the knob, the precision resistors, the wiring and the calibration time. In addition, it limits the range that's able to be set directly from the panel.

While I don't have a absolute number, I'm guessing the Octave switch would add around $15-20 to the price.

Are you OK with a Coarse tune pot? I know that for most things, I am.

Just me · Post by **Just me** » Fri Dec 24, 2010 5:12 pm

Q-106 sine is close enough, that's what I use now. (And it is only slightly discernable from a pure sine from another ZO. ) Jumper select would be fine, too. Then it would work for more peoples needs/uses. (Cause as an FM modulator for a ZO, there probably isn't much call. They aren't really common.)

dslocum · Post by **dslocum** » Sun Dec 26, 2010 9:54 am

OK. How about SINE always available from one output jack, and the other output selected from the WAVE switch? Seems to solve alot of requests.

No DOTCOM soft sync option.

Buffered Oakley CV/Gate Buss behind. Still waiting for someone to clarify some questions. Help please.

darwingrosse · Post by **darwingrosse** » Sun Dec 26, 2010 10:26 am

dslocum wrote:OK. How about SINE always available from one output jack, and the other output selected from the WAVE switch? Seems to solve alot of requests.

No DOTCOM soft sync option.

Seems fine with me (although I'd use the soft sync option, I'm not going to be a hand-waver). I'm one of the people that would be using the sine output consistently.

Do you have a shooting-for price yet? Sounds like I need to start saving up, 'cuz I'm mesmerized by the prospect.

dslocum · Post by **dslocum** » Sun Dec 26, 2010 10:47 am

Ok. (Yeah I say that alot)

I'm _shooting_ for somewhere around $250 to $275 USD. I know it's a bit more than some other modules, but it really takes a good bit of engineering, tweeking and burn-in to get it right. I'm hoping it's a reasonable figure. As we ramp up production into the hundreds (yeah right), we could get the price lower. 8_)

darwingrosse · Post by **darwingrosse** » Sun Dec 26, 2010 7:30 pm

dslocum wrote: I'm _shooting_ for somewhere around $250 to $275 USD.

Sounds reasonable to me...

essex sound lab · Post by **essex sound lab** » Mon Dec 27, 2010 8:54 am

dslocum wrote:Buffered Oakley CV/Gate Buss behind. Still waiting for someone to clarify some questions. Help please.

Cool. I think this is really important to one of the "demographics" for the module (at least it is to me).

I'm afraid I can't comment on the Oakley buss...the only VCO buss I have familiarity with is the MOS-LAB buss (which is documented on the MOS-LAB site, I believe).

7thDanSound · Post by **7thDanSound** » Mon Dec 27, 2010 2:35 pm

This is my last take on this, if it comes true (or maybe even otherwise too) and will be available in .com format I'll take three!

I want everything like the graphic mockup previously in this thread with coarse tune and all except for this:

Instead of 1V CV out, I want a square one octave below.
I want a chain-able buffered 1V/CV from the input jack on the PCB so I can daisy chain modules.
I don't care if it's triangle or sine on the selectable output but I'd prefer it jumper selectable on the PCB.

Price range is cool with me.

dslocum · Post by **dslocum** » Fri Jan 07, 2011 12:50 pm

For discussion...

I'm planning on adding a "buss drive" output opamp follower (no current limiting resistor) and connector to each VCO. This will waste an opamp on each "slave" VCO on the buss, but it seems a small price for bussing capability! I've attached a quick / modest drawing. PLEASE let me know what you think. Is this in a spirit of the Oakley buss and a reasonable implementation?

Bryan B · Post by **Bryan B** » Fri Jan 07, 2011 2:02 pm

That would be a great feature for this!

I think bussing should be a higher priority than it is in the current market. This is a good step forward.

theinnerpalm · Post by **theinnerpalm** » Fri Jan 07, 2011 3:53 pm

this is exactly what i need for a my small 5u cabinet. would definitely buy, pretty much no matter which path you take design wise.

with multiple bussed together what does this accomplish?

i agree that the thru could be used for something more useful

looking forward to hearing more

Heathfinnie · Post by **Heathfinnie** » Fri Jan 07, 2011 4:47 pm

edited...

Heathfinnie · Post by **Heathfinnie** » Sat Jan 08, 2011 3:59 pm

edited...

fac · Post by **fac** » Sat Jan 08, 2011 5:06 pm

7thDanSound wrote:This is my last take on this, if it comes true (or maybe even otherwise too) and will be available in .com format I'll take three!

Price range is cool with me.

Me too. I'll take at least two, but most likely three.

I also prefer using the busing system instead of the 1V/Oct output, and using that output for something else (a sub-oscillator sounds tasty, but it's not a must).

dslocum · Post by **dslocum** » Sun Jan 09, 2011 2:04 pm

theinnerpalm wrote:with multiple bussed together what does this accomplish?

If you MULT a normal voltage output of say a keyboard, the calibrated 1v/Oct inputs will slightly load down the outputs due to there normally being a small current limiting resistor (usually 1000 ohms) on synth outputs. Since tuning is so critical and the VCOs have a 100,000 ohm input, they start dragging down the output. The more VCOs you add to the output thru normal MULTs, the flatter the 1V/Oct goes at the high end.

The internal bussing scheme eliminates this current protection resistor and is therefore able to drive several VCOs without detuning. That's why there's so much interest.

megaohm · Post by **megaohm** » Sun Jan 09, 2011 2:31 pm

dslocum wrote:
theinnerpalm wrote:with multiple bussed together what does this accomplish?
The internal bussing scheme eliminates this current protection resistor and is therefore able to drive several VCOs without detuning. That's why there's so much interest.

Have you thought about a bussing scheme that operates behind the scenes (behind the panel)? That way you can get the extra jack for another waveform (or whatever) and still have the 1V/Oct buffering. You could use .100 two pin headers and connectors and NC switch jacks to normal the modules together. If you want to bypass the normaling you can simply patch into the module's 1V/Oct jack.
If people buy two or three of these and place them together, behind the panel normaling like this should be no problem for anyone.

p.

dslocum · Post by **dslocum** » Sun Jan 09, 2011 2:41 pm

megaohm wrote:
dslocum wrote:
theinnerpalm wrote:with multiple bussed together what does this accomplish?
The internal bussing scheme eliminates this current protection resistor and is therefore able to drive several VCOs without detuning. That's why there's so much interest.
Have you thought about a bussing scheme that operates behind the scenes (behind the panel)? That way you can get the extra jack for another waveform (or whatever) and still have the 1V/Oct buffering. You could use .100 two pin headers and connectors and NC switch jacks to normal the modules together. If you want to bypass the normaling you can simply patch into the module's 1V/Oct jack.
If people buy two or three of these and place them together, behind the panel normaling like this should be no problem for anyone.

p.

Paul,

That's what I was trying to show in the diagram a few posts ago. The buss would be Oakley's 3 pin pinout and internally bussed. Did I miss something in what you said?

megaohm · Post by **megaohm** » Sun Jan 09, 2011 2:41 pm

Oops.
I see that 7thDanSound already suggested this on Dec 27.
It would also eliminate a couple patch cords. That's always nice.

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MU single width VCO Ideas