MFOS VCO, anyone built it?

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StkMtd
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MFOS VCO, anyone built it?

Post by StkMtd » Thu Mar 11, 2010 10:39 pm

Hi all, new here.

Looking up pricing for building one of these:

http://musicfromouterspace.com/analogsy ... 4REV0.html

Wondering if anyone's built it. How do you like it? Got some samples for me?

I was originally considering a Doepfer dark energy, but I love building things more than buying them. Also, for lest than the cost of that thing, I can build 3 or 4 of these.

One thing I'm having trouble finding is a good price on pots and knobs, as well as a 5000 pF silvered-mica capacitor. Mouser carries them ($9 for 1, and $20 in shipping to Canada :X). Where are the hook-ups at?

So far my cost is going to be around $70 + $8 shipping for the parts, and about $13 for the aluminum plate (from a supplier in town, I'll have to drill holes myself).

Also, is there a standard size for racks? Or is this something of a personal taste? If I make this one 10" tall as the design specifies, I'm guessing any other modules I add to the rack will have to follow this sizing.

Thanks for your time, and hope to have many adventures here :)

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haricots
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Post by haricots » Thu Mar 11, 2010 10:45 pm

Tried and failed. :despair: Granted it was my first module.

I used the faceplate for my PS3100 resonator module this week! Now I just have to spray paint over the existing graphics.

StkMtd
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Post by StkMtd » Thu Mar 11, 2010 10:53 pm

haricots wrote:Tried and failed. :despair: Granted it was my first module.

I used the faceplate for my PS3100 resonator module this week! Now I just have to spray paint over the existing graphics.
If I might ask, what problems did you run into?

P.S - love the track on your bandcamp page. Reminded me of a very modern sounding kraftwerk.

EDIT: are you in Guelph, Ontario?

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haricots
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Post by haricots » Thu Mar 11, 2010 11:06 pm

Honestly, it really was my first attempt at a module - a little ambitious I would say. I'm sure I could build it now but haven't bothered to buy the board and parts again because I have 3 vco's in my setup and don't really need any more. That's why I've reused the Bridechamber panel for something else. I couldn't get it to track properly and the sine output was silent.

Yep, in Guelph, Ontario. Where are you?

StkMtd
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Post by StkMtd » Thu Mar 11, 2010 11:59 pm

Cambridge. Next door, practically.

This was going to be my first module... I may reconsider. Anything that would just let me control some kind of osc with a voltage. I don't really have access to an oscilloscope, but I have thought of all kinds of ways of tuning it (a combination of a guitar tuner and by ear :P)

I've been diddling with electronics for about 4 months now, picking it up quickly, and this looked like a fun, doable project (even if I never got around to tuning it properly).

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Post by loydb » Fri Mar 12, 2010 12:13 am

I just did a fresh BOM for them (see http://www.electro-music.com/forum/topic-40321.html). About $51 in parts, not counting knobs and panel. When I finish the WSG I'm working on, that's my next build. I want to make a couple of them before I tackle a Living VCO or a MOTM 300.

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Post by StkMtd » Fri Mar 12, 2010 12:45 am

loydb wrote:I just did a fresh BOM for them (see http://www.electro-music.com/forum/topic-40321.html). About $51 in parts, not counting knobs and panel. When I finish the WSG I'm working on, that's my next build. I want to make a couple of them before I tackle a Living VCO or a MOTM 300.
I'd have a look but I hate how slow OO is :P I'm making mine in google docs. Mind telling me where you found the best price on 5000pF silvered-mica caps?

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Post by neandrewthal » Fri Mar 12, 2010 1:40 am

I've got a couple of the old "new and improved" version and I like them just fine. I can't really say much about the sound because I am an idiot when it comes to those things, a saw is a saw and a square is a square to me. I could never get a really nice sine, though and the stability is not the best for finely tuned FM patches, but it was one of my first builds, those things are probably my fault and I have new VCOs to do those things. The MFOS hold up just fine for my regular workhorse VCO duties.

I don't remember what caps I used in mine, but if I were building it now, I'd use these ones:

http://au.mouser.com/ProductDetail/Xico ... iOPzqxtvI=

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Post by StkMtd » Fri Mar 12, 2010 2:49 am

Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:

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Post by werock » Fri Mar 12, 2010 6:55 am

StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
Maybe a friendly neighbouring wiggler could add that on to an order they are doing, in exchange for something? Just a thought.

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Post by falafelbiels » Fri Mar 12, 2010 7:07 am

I built two and they are actually pretty nice. I'm pretty much with Neandrewthal on the sound thing, however it is the first oscillators in which I enjoy the sound of the sync feature. I built a dual version and they do nice FMing, although I don't really know "proper" FMing so well.
When I couldn't find that Mica cap, a friend of mine advised plain ceramic ones and they work good enough for me. You won't see me playing it from a keyboard mind you...
To be honest I can't get one of them to show a proper sine- or tri- wave on the scope, but it sounds good!

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haricots
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Post by haricots » Fri Mar 12, 2010 9:23 am

StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
I could pull the one from my failed build for you if you want. No guarantees it works though. :)

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Post by mome rath » Fri Mar 12, 2010 11:11 am

loydb wrote:I just did a fresh BOM for them (see http://www.electro-music.com/forum/topic-40321.html). About $51 in parts, not counting knobs and panel. When I finish the WSG I'm working on, that's my next build. I want to make a couple of them before I tackle a Living VCO or a MOTM 300.
what is that .ods file format?
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Post by sduck » Fri Mar 12, 2010 11:19 am

StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
Mouser does have a USPS shipping option which you (and everyone else) should definitely use. I use it all the time. Much cheaper, just as fast.
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johnnymad
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Post by johnnymad » Fri Mar 12, 2010 11:30 am

i've built three. i never really calibrated them, so they don't track really well. they're great for drones though.

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krelnarb
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Post by krelnarb » Fri Mar 12, 2010 2:23 pm

Well, it sounds like they would be just dandy used with wave shapers.

Has anyone used the Bridechamber kit?

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Post by neandrewthal » Fri Mar 12, 2010 2:48 pm

sduck wrote:
StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
Mouser does have a USPS shipping option which you (and everyone else) should definitely use. I use it all the time. Much cheaper, just as fast.
Yeah, $20 doesn't sound right. Costs me $8 to Sudbury.

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Post by StkMtd » Fri Mar 12, 2010 3:20 pm

sduck wrote:
StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
Mouser does have a USPS shipping option which you (and everyone else) should definitely use. I use it all the time. Much cheaper, just as fast.
The $8 USPS service is not guaranteed, and can get held up at customs. Also no tracking. I just love how Digi-Key will get it to my door within 24 hours through UPS for $8. Mouser is kind of a let down by comparison.

Well, if anyone is putting in a Mouser order and you're anywhere near Cambridge, ON, drop me a line. I may have something to trade you, or I'll just straight up pay you the cost of them. At the price I'd probably grab 20 of the polystyrene ones.

This still leaves the question of pots. Is there some kind of secret source for them, or are you pretty much at the mercy of the distributors prices?

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Post by sduck » Fri Mar 12, 2010 5:47 pm

Yes, I should have mentioned that my experience with mouser and their shipping is strictly from a USA to USA perspective - once you start shipping through borders, everything changes.
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Post by bonusplays » Fri Mar 12, 2010 7:02 pm

I build two, the first SDIY projects I did, just last year.

They sound great. I wish I had an oscope and could calibrate them better.

I am planning on revising some parts per Ray's new PCB (I did the previous version) and I want to swap out the LM394 for an SSM to improve tracking for +/- 15V. Though I don't ever expect tracking to be 100%, just my gut feeling.

If I was going to start with an MFOS module, in hindsight, I'd do the dual VCA. Easy build and they work relatively well with very little calibration.

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Post by chocolatyshatner » Fri Mar 12, 2010 7:55 pm

I built two of the last revision oscillators /w parts kits from Bridechamber for +/- 12v operation. Worked out quite well for me. The pulse and ramp wave sound good to me, the triangle sounds softer compared to my rawer sounding Anti-Osc tri. I think that I read that there's a slight glitch at the peaks of the triangle when calibrated correctly, so some minor filtering doesn't suprise me. I could never get a really "sine" sounding sine wave (no scope), so I just set the waveshapers to where I thought it sounded cool :mrgreen: I accept that.

Tuning was a bit of a pain, but mine have pretty good tracking over 4 octaves, which works for me. Reading the info on the newest revision leads me to believe that the tracking has been improved.

I REALLY like the sync sound of these, especially when sycing to the Anti-Osc mayhem out. All sorts of changing harmonics to grab onto. Whee!! :sb:

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Post by haricots » Fri Mar 12, 2010 10:59 pm

neandrewthal wrote:
sduck wrote:
StkMtd wrote:Ahh yes, he does mention you can substitute a Polystyrene cap... let's see. 30 cents for the cap, 20 bucks for the shipping :doh:
Mouser does have a USPS shipping option which you (and everyone else) should definitely use. I use it all the time. Much cheaper, just as fast.
Yeah, $20 doesn't sound right. Costs me $8 to Sudbury.
but

I mentioned in another post that Mouser will not refund any orders lost using the USPS shipping option to Canada anymore. They are having way too many problems with USPS>Canada Post lately. My last order cost me $20 via Fedex but I had it one day. The order before that never arrived but they thankfully credited my account (and told me they would not do so again, and to use Fedex).

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