Feeler: VCQO Circuit Board

Hi all, I've been kicking around the idea of printing up a couple VCQO boards for experimenting with other projects and wanted to see if there was any interest in these. This is the same VCQO that's in the Z-5, originally designed by LSDC. This is a very solid quadrature oscillator providing a very clean sine and cosine wave, there are 7 of these in the Z-5; 3 for the regular oscillators, 3 for the rotators and one for orbit. It has 2 inputs to control output frequency, you only need to apply +/-15V to one input to get it to work. The second input can be from another signal source such as an LFO. This outputs sine and square waves. In the Z-5, for the 3 main oscillators I use .0047uF caps which gives up to about 600Hz. For rotation on the Z-5 I use .22uF caps which gives about 10Hz with + or - 15V on the input.

When the input signal is at +15V the oscillator is running at max speed, which is dependant on the timing caps. As you reduce the input voltage the frequency decreases until you reach 0V on the input, at this time the output frequency has stopped and as you continue past 0V and head toward -15V the sine/cosine signal begin going the other direction.

So, depending on the number of boards I can have printed, I'm hoping to be able to offer these at around $50-$75, plus shipping. Or maybe just the bare boards if you want to populate them yourselves, I'll have to check on the per board price, likely around $15 but again it depends on the number of folks that are interested.

Here's a quick demo video of the output of the VCQO: https://www.youtube.com/watch?v=s_LK76BnjF0

I've also attached a pic of what the board would look like. Disregard the silk screen layout, a few changes still need to be made to clean it up, but this is about what it will look like. Also, the board measures in at 100mm x 40mm

Attachment 42940

Any interest in these?

sorry

what is it?

YesPlz!!! Interested!

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Originally Posted by andy_con

sorry

what is it?

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A quadrature oscillator is the foundation for an analog console. It's the "old fasioned" way of making abstract, all analog, no digital. Having a high quality quadrature oscillator is extremely important and this particular design does a fantastic job.

CountFunkula, you in for 1? I'm thinking I'd need about 5 or so. I don't think it's going to be cost effective unless we get about 20 or so on the list.

I would be in for at least one. Possible two by the time SELEM rolls around. Not sure what your time frame for this is but one for sure. I would want fully populated ready to output for 50-75.

Why not just use DDS generator for this?

I'm interested. Would be fun to try and build one.

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Originally Posted by Bbe

Why not just use DDS generator for this?

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this is my question, too

However, i' m in for 1 to help get you to the desired number :)

(i suppose there will be smd parts involved, making it not too easy to assemble one myself, right?)

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Originally Posted by Bbe

Why not just use DDS generator for this?

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I know this can be done digitally, heck, maybe even cheaper? There is just something about the analog circuits that I prefer. I can't really explain it, I suppose. My step father runs a guitar shop and was in a band many decades ago. Even to this day he swears by the old tube amplifier. Perhaps an analogy can be drawn from this. Similar to the old ions.

It is also a lot easier to turn a few knobs and flip a few switches than it is to point and click... *retardo

So it looks like I'm at about 9 boards at the moment.

Hello,

I would like 2 bare boards.

I hope this helps you get the cost of the boards down for everyone.

ED

in such a case it would be great if you added a saw and square generator as well as the simplest fx (eg AM/FM) section :o

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It is also a lot easier to turn a few knobs and flip a few switches than it is to point and click...

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Originally Posted by Bbe

in such a case it would be great if you added a saw and square generator as well as the simplest fx (eg AM/FM) section :o

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Bbe, that's already available, it's called the Z-5!*retardo

This is just the quadrature oscillator from the Z-5, this board outputs sine and square. The rest of the main Z-5 board has a saw and square LFO which is used to AM modulate the signals from the VCQO's via a VCA. And(or) you can FM modulate the signal with the 2nd input on the VCQO. Like I said, this is just the VCQO, which can be used in a number of other projects or a mini abstract generator can be made with a couple of these boards plus some other support circuitry.

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Originally Posted by DZ

...the VCQO, which can be used in a number of other projects.....

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If I ever get up to the point of getting a Z-5, which you have no idea how badly I want one, these would be great for building color mods.

Oh, I missed it .. your Z-5 definitely monster :)

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Bbe, that's already available, it's called the Z-5!

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Are you planning to develop Z-6 with motorized faders and buttons, or maybe Z-7 with digital potentiometers? It opens up many possibilities for the control of this generator, although it will not be a old school device from the 80s *retardo

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Originally Posted by absolom7691

... these would be great for building color mods.

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I was thinking along the same lines. I was going to take a stab at color modulation with a micro controller, but analog would be fun to play with.

-Sal

Quadrature for color mod? Why? Even back in the day Laserium's color mod was "digital". Today with RGB systems you almost have to go digital...

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Originally Posted by laserist

Today with RGB systems you almost have to go digital...

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Laserist, can you elaborate on this a little more. If I am trying to mimic an analog signal by using a DAC output for each of my colors why wouldn't I want analog directly? Yes if I am trying to get a very specific color I may want control of individual steps per color (digital) but if I just want a rainbow of colors to flood my pattern while being AM modulated around the pattern I can see the fun in true analog color modulation.

I guess my though is just because Laserium didn't do it doesn't mean there isn't a place for it today. There is room for all kinds of art performed in all kinds of different ways.

For color mod you're traditionally working with full on colors. A bipolar sine wave when you're driving a galvo to whip beam around isn't horrible, but it's not that useful for analog diode drivers, and the cosine output might generate something interesting, but only as a subset of what could be done...

Ok, so it looks like if we wanted to do this I would need to have about 10 boards printed. I'll take 4 and 6 for other folks. At 10 boards we'd be looking at $18.00 per board plus whatever it cost to ship to you. If you just want the board, no problem, it will come with a parts list and I'll put together a video on how to tune them. Note, you will need an oscilloscope.

Or, if you want a fully populated board that's tested and tuned it will be $55.00 plus shipping.

If anyone else signs up for one the price should drop a little bit. I figure by the end of next week I'll close this out, accept payment and get the orders put in. lead time would probably be about 3-4 weeks for the assembled boards and probably less for the bare boards.

Thanks!
David

Dz,

Could you please put me down for three of these, sorry I'm a little late to the party :) I'll take them fully populated please

Many Thanks

steve

There is a little voice in my head saying yes, get one. Just to tuck away. Populated of course. You don't really expect me to have the time to solder anything do you??

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Originally Posted by Bradfo69

There is a little voice in my head saying yes, get one. Just to tuck away. Populated of course. You don't really expect me to have the time to solder anything do you??

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LOL!

Sounds great guys, I'll update the price next week but with an added 4 it should drop by a few bucks already.

Hi all, I'm going to have to put this on hold for a while. My intention was to use these to test the foundation of a color mod circuit, however I have something much much better in the works. If you really need one of these boards for a project of your own, let me know and I'll see what we can put together.

I don't need one. Just helping reach the target qty
So, let us know of the "something better" as soon as you can

:)

No Problem, just keep me informed, it was just to have a nostalgic play with a couple of ideas.

Cheers

Steve

Uh.... no rush. :D

I'm good on waiting. No rush.

Wow, I realize this thread is now nearly 3 years old.. Well the good news is that these are sort of available now. I finally finished up the circuit board design after the recent FLEM and had them printed. I have enough parts to populate 2 boards and can get more parts in to do the rest, if there's much interest in these. The money from the first one that sells will be donated to PL!

Details here: VCQO

OK, I'll bite. One unit. Whats your paypal?
Steve

Can you send me the receipt of an $85 donation to PL? Then send me your mailing address and I'll get one sent out to you.

Thanks,
z

Donation sent...
Email Sent


Steve

Very good. The board will ship out Thursday or Friday.
Additional details about the board can be found here: http://aldebaran-systems.com/Supt_VCQO.htm

Thanks

:cat:
Watching this thread with great interest, but I am unclear about how this board works.*retardo
I am looking for a QO that is based on an individual step input pulse which calculates each cosine output value from the previous sine value and vica versa in such a way that as the step increment size/output frequency is reduced the precision will increases enabling it to be used equally well as a very low FQO or a high FQO.:cool:
This would work by changing the step increment size rather than the individual step frequency thus avoiding any direct harmonic relationship between the step frequency and the output frequency whilst using different step frequencies for each VCQO >:)
Hopefully this would produce "live" results which could never be totally synchronized ,but should be stable enough to not wobble like crazy without being dead as a dodo like typical digital circuits with a common step drive frequency.*vigil

Any chance that this board would do this ?:question:

Cheers :)

Cat, this is a very stable VCO with a stop or sample and hold on the oscillator.
!
PM me, I have a design for what your asking for. There is a trick to it, using a slightly unstable source with dither, I just don't feel like enriching the copycats by posting it.
Abstracts need to be done with care, not mass produced crap.
!
Steve