Living VCOs

janvanvolt · Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany

Hi all,

i finally figured out what the problem was with my LVCO ...

Nwo some questions with regards to the cabling. I am using the Bill&Will Version (7U with Waveshaper).

a)
What i couldn't get to work correctly is the Octave Switch (4'/8'/16') as only one part of it is working. I am using a DPDT on-on-on switch. Alternatively i got a MTS-2 Switch (also DPDT e.g. 6 pins). What is the correct wiring for this ?

b)
The Linear VCO detuning does not seem to have any effect on the VCOs

c)
What is the correct wiring for the VCO1 PW/PWM Switches ?

d)
1V/Oct Front-Adjust: How to wire this as well ?

Thanks for any help in getting this issues fixed ( and ready for the upcoming Happy Knobbing this weekend)

numbertalk · Posted: Sun May 23, 2010 8:36 am Post subject:

Hi Jürgen,

I have found something with my Living VCOs. I have all 3 VCOs' V/Oct scaling calibrated very well. I did them all individually - I turned tracking from the driver off for each and used each VCO's individual V/Oct input with my Midi-to-CV converter unit. But then when I then check the scaling from the driver's V/Oct input and set each VCO to track the driver, each one is very off. I have the driver's vibrato depth all the way down,the driver's tune is close to center - when switching tracking on I tweak it a little to tune from the low note on my keyboard (it's close - don't have to move tune very far from centered) but then when I play the highest note on my keyboard, they are all 3 very sharp.

Have I done or am I doing something wrong?

jhaible · Posted: Sun May 23, 2010 9:03 am Post subject:

If you're using some of the individual CV inputs for precise V/Oct control, you need to match the 100k resistors to 0.1%

JH.

numbertalk · Posted: Sun May 23, 2010 9:38 am Post subject:

Ah, I thought I might have done this, but guess I didn't.

So it sounds like I should just calibrate using the driver's V/Oct input, then, right? In that case should I use the driver's tune knob on the panel or the frequency vernier for each individual VCO when going back & forth with the trimmers to calibrate, or does it not matter?

Also, just to confirm, it sounds like the individual CV inputs are better strictly for FM/vibrato and not as keyboard-tracking inputs? Good to know.

Thanks!

jhaible · Posted: Sun May 23, 2010 10:57 am Post subject:

numbertalk · Posted: Sun May 23, 2010 11:01 am Post subject:

Thanks!

numbertalk · Posted: Mon May 24, 2010 6:04 am Post subject:

I went back and checked and I did use actual .1% precision resistors, 50ppm as well, for all of these *except* R137, R141 and R144.

Also the interesting thing is, to be clear, I am able to get each of the individual V/Oct inputs to scale great over a wide range. I am also able to get the 3 VCOs to scale to the driver's global V/Oct input over that same range. The problem is that these do not match up - if I calibrate to one then the VCOs do not scale properly to the other. Does this make sense? Could this simply be because of these 3 resistors, if all of those others are .1% resistors?

Right now I have it scaled to the driver but it would be nice and give me some flexibility to also be able to use the individual inputs as well.

Thanks again.

jhaible · Posted: Mon May 24, 2010 10:02 am Post subject:

numbertalk · Posted: Mon May 24, 2010 10:18 am Post subject:

frenchyinmunich · Joined: Jun 23, 2009 Posts: 115 Location: Germany

Hello,

I built few living vco and I find them very stable.
It reminds me the ARP2500 VCOs.
Is there someone here who did a waveshaper for it?

f

loydb · Joined: Feb 04, 2010 Posts: 393 Location: Providence, RI

Is there an FPD file for a layout like JH has on his web page? I like the asymmetric layout a lot. I've got two of these puppies I need to start building...

Thanks!

Mr.TorsionTorque · Joined: Jun 05, 2010 Posts: 14 Location: Minsk, Belarus

Hi there... I'm considering ordering the VCOs but I've got one question.
Is hard syncing of OSC's is possible in a way of mod or something?
Thanks in advance for the answer and sorry for my English.

Noiseconformist · Joined: Aug 05, 2008 Posts: 27 Location: Vienna

jhaible · Posted: Tue Jun 08, 2010 12:11 pm Post subject:

Mr.TorsionTorque · Joined: Jun 05, 2010 Posts: 14 Location: Minsk, Belarus

THX for the rapid answer, thats a good idea to think about... Smile

LetterBeacon · Joined: Mar 18, 2008 Posts: 454 Location: London, UK

Sorry to ask a simple question, but what exactly is a 10-turn potentiometer? Does it mean it rotates fully 10 times? Why is that better than using a coarse and fine pot?

Is this a suitable pot:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=5222974

£12 each! Are they always that expensive??

Thanks!

jhaible · Posted: Tue Jun 29, 2010 10:00 am Post subject:

LetterBeacon · Joined: Mar 18, 2008 Posts: 454 Location: London, UK

Thanks for the reply!

I'd like to go for the 10-turn pot for all the reasons you mentioned, I just want to know what the advantages are (apart from using 1 pot instead of 2).

So is a 10-turn pot a pot that goes round 10 times? Does it mean you can be more precise with it, so you don't need a fine tune?

jhaible · Posted: Tue Jun 29, 2010 1:35 pm Post subject:

zarko · Joined: Mar 25, 2010 Posts: 22 Location: France

Hello All.
Hi Jürgen.
I just finished the wiring of the Living VCO's,and they are fonctional as entended,and sound verry fat Wink

but i have a problem with the tracking v/oct on two vco's, just one is ok and take me less than five minutes to set up,but for the two other imposible to scale correctly.
i go to try explaying in my aproximative english.
Wiring is ok ,i test all the components in ohmmeter mode and i compare all the values with the functional one, and all its ok.
For the tracking i do this:
i connect a cv source directely on the VCO V/oct.
first i ajust the freq trimpot to have 16,20hz for the zero position.
after i aply a CV of 0V and turn the potentiometer knob to obtain 55hz on my freq counter after this i aply 1V and i read 102hz,i ajust the scaling to obtain 110hz. I turn back in 0V CV and i read 57hz, i readjust the freq pot to have 55hz again, after i aply 1V CV again and i read 102hz and this indefinitively until the timpot is in the maximum
range.each time i reajust the freq knob because the freq goes up, the tracking freq goes down.
Here is my problem,i suspect the CA3046 maybe a problem with the unmatched pair?
Lets me know if one of you having the same problem.
Thank you, Regards
Fred

jhaible · Posted: Fri Aug 20, 2010 2:13 pm Post subject:

zarko · Joined: Mar 25, 2010 Posts: 22 Location: France

Thank or the reply,i try this tomorrow Wink

zarko · Joined: Mar 25, 2010 Posts: 22 Location: France

Hi Jürgen

All works fine now Very Happy

for the second time i make a neewbe error, in fact its the same procedure to tune the Yusynth CVO, i don't know why i thinking that it was a different way, here was my error Embarassed

Thanks.

The Bad Producer · Joined: Mar 08, 2009 Posts: 282 Location: The Manhole

Hello all,

Just wanted to say, having just now finally finished my fourth Living VCO, how great they are!

I added the Saw - Tri - Sine waveshaper circuits from Electronic Peasants diagram on page 12 and they really add so much versatility to an already great design! Linear detune on Sine waves is something else!

Having these has and will open up so many musical possibilities to me...

So thank you Juergen for the amazing VCO, and thank you also to Electronic Peasant, Ray Wilson and Ian Fritz!

Very Happy

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LetterBeacon · Joined: Mar 18, 2008 Posts: 454 Location: London, UK

That looks fantastic!

Do you have a stripboard layout for the waveshapers?