ARP Odyssey Oscillators

funkyfarm · Posted: Fri Jan 23, 2009 10:08 am Post subject:

mki...mkiii... Embarassed

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

e-grad · Joined: Sep 12, 2008 Posts: 142 Location: Berlin

It should be triangle out!?

numbertalk · Posted: Sun Feb 01, 2009 4:35 pm Post subject:

Thanks!

It's a Triangle wave output. I'm adding a sine & triangle out for LFO use:

http://www.electro-music.com/forum/topic-30667.html#224604

numbertalk · Posted: Fri Feb 06, 2009 12:12 pm Post subject:

Hi Andy,

The docs you posted specify that the Manual PW pot is wired as a voltage divider between 0V & -15V - I just wanted to verify how to correctly wire this to the pot - would -15V go to the CCW lug and ground to the CW lug or vice-versa?

Thanks!

Broadwave · Posted: Sat Feb 07, 2009 10:20 am Post subject:

numbertalk · Posted: Sun Feb 08, 2009 7:35 pm Post subject:

Thanks Andy!

Finished wiring up and trimming my board tonight and it all works! Need to etch and wire up the saw-to-tri converter and get brackets in an order I'm waiting on from Bridechamber then I can mount it in my synth! Here are a couple photos - the wiring is a total rat's nest at the moment.

I'm at my upload max so photos linked from Flickr.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

numbertalk · Posted: Mon Feb 09, 2009 12:56 pm Post subject:

Thanks Chris!

I love it - the sync sounds really special, as expected.

Jaba · Joined: Feb 27, 2009 Posts: 48 Location: Genova, Italy

Hello,

I know this thread has been silent for about a month, but I'll try the same...

first of all, thank you all for sharing a lot of interesting info here

then straight into the hard stuff:

- looking at the ARP Odyssey's service manual, on the board B-II PCB, I can clearly see a thin copper track running around some components (maybe some sort of a shielding, I don't know) in each oscillator, connected to the source of Q16 for VCO-1 and to the source of Q9 in VCO-2; in the schematic on previous page, it is represented by a dashed line;
well, is there a reason why it has not been copied in your clone PCB for VCOs ? I guess it was there for a reason, does anybody know ?

- has anyone thought about adding linear FM inputs to these VCOs ? to me, it would definitely make them my ideal oscillators, since nothing else is missing that I would want

Broadwave · Posted: Wed Mar 11, 2009 11:16 am Post subject:

funkyfarm · Posted: Thu Mar 12, 2009 2:09 pm Post subject:

On MKI schematic, all cv are summed and connected to the tempco resistor and to dual trannies TZ281. (i guess this is the famous expo converter)

Linear input consists in adding in parallel of this converting circuit another circuit based around only one NPN transistor.

Far beyond my skills Smile

vtl5c3 · Posted: Sat Mar 14, 2009 7:54 pm Post subject:

I just etched two PCBs for this baby. Looking forward to doing Autobahn covers with them.

If I like this vco as much as I think I will, I'm going to do a press n peel layout for the 2600 VCO. It's super simple, and you know it's a cool sounding oscillator! afro

funkyfarm · Posted: Mon May 11, 2009 9:22 am Post subject:

monokinetic · Joined: Aug 01, 2006 Posts: 100 Location: prague

funkyfarm · Posted: Tue May 12, 2009 1:45 pm Post subject:

That's correct, two distinct discrete vcos.

Looking at this : http://electro-music.com/forum/phpbb-files/arp_odyssey_dual_vco_126.pdf

The red square pad is 1V/Oct cv input for both vco ; it is connected to VCO1 Audio/lfo switch (1V/O CV input for VCO1) AND to a 49.9k resistor and VCO2 scale trimmer (this point is 1V/O CV input for VCO2).

So just cut the trace under the Audio/lfo switch symbol.

monokinetic · Joined: Aug 01, 2006 Posts: 100 Location: prague

Cheers funkyfarm, that saves me a bit of valuable time!

David

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

Is it a good idea to use ferrite beads instead of jumpers at the top of the PCB? It looks like Andy used resistors on the board in his first post....

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numbertalk · Posted: Sat Jun 27, 2009 10:11 am Post subject:

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

Whoops, I was sure I read through the thread before I asked that question!

Thanks!

hway23 · Joined: Jul 23, 2008 Posts: 61 Location: ks

did a manufactured pcb ever surface for this? I would love to have me a couple o' oddy vco. Cool

Broadwave · Posted: Thu Aug 13, 2009 11:09 am Post subject: