Sound Lab Builders! Check out the MFOS Mini-Controller.

adhdboy · Joined: Feb 16, 2005 Posts: 57 Location: denver

Hi All

If you have built a Sound Lab or are planning to you might want to check out the MFOS Mini-Controller. It's a 1V/Octave controller with a probe type mini-keyboard. It adds a new dimension to having fun with synth-diy.

http://www.musicfromouterspace.com/analogsynth/MFOSMINICONTROLLER/MFOSMINICONTROLLER.php

Cheers

Ray

v-un-v · Posted: Fri Feb 01, 2008 11:27 am Post subject:

Hi Ray!

Long time no see!!

Yes- we're just discussing it. Personally I'm not to sure about that case- I know you had your reasons etc...... Shocked

No worries. I'm just in 'wind-up' mode! Very Happy

Pehr · Posted: Fri Feb 01, 2008 12:37 pm Post subject:

Very cool project Ray! I'll put it on the 'to do'-list Very Happy

adhdboy · Joined: Feb 16, 2005 Posts: 57 Location: denver

I was going for a miniature vintage wooden case synth look. I kind of like it (but I'm biased). I could definitely see building the Sound Lab, Mini-Controller and Wall Wart into a kind of ARP Odyssey looking kind of thing. That would be totally cool and I may do it... just to do it.

Cheers

Ray

hackbox · Joined: Jul 27, 2007 Posts: 134 Location: Australia

Pehr · Posted: Sat Feb 02, 2008 3:36 pm Post subject:

I bet you could fit your SL right on top of that case. What an awesome setup! Cool

nice mp3 too Smile

hackbox · Joined: Jul 27, 2007 Posts: 134 Location: Australia

Zodiak

Oh boy thats fantastic!!! Laughing

And these guys are going to be lining up to buy one http://www.youtube.com/watch?v=KfZV6e677pQ&feature=related Laughing

Wild Zebra · Posted: Wed Feb 06, 2008 8:48 am Post subject:

Yep, have to put it on the ever growing list.

PoindexterLabs · Joined: Jun 07, 2007 Posts: 12 Location: North Carolina

So I've almost finished with my mini-controller, but I've come to a few spots on the board that have little abbreviations by them, but I don't know where they go or what they do.
On the far left of the board is "KBUS"
On the far right is "KBTP"
I've looked back over the schematic and it's my thought that KBUS is the wand you use to play the "keys".
KBTP on the schematic is just referred to as another abbreviation "isrc".

There are also the appreviations "GLA" and "TLA" that I can't figure what to do with.
I swear I'm not an idiot. My brain is just fried. I know there is an easy explanation for all of these that will embarass me with its simplicity.

Any and all help is appreciated.
Oh, and any suggestions for what to use for the little note wand. I was going to hollow out a PDA stylus and run a wire through it, but I'm very open to other suggestions.
Many Thanks.

hackbox · Joined: Jul 27, 2007 Posts: 134 Location: Australia

If you look at the trace on the board, it goes to "GLP1" which could be glide.
The other trace leads o the last "key".

Now it could be Key Bus Tip?
Or maybe you just ignore it?

Got mine today Smile

PoindexterLabs · Joined: Jun 07, 2007 Posts: 12 Location: North Carolina

Built it and love it. I house both it and my sound lab in a child's upright piano. I got one cheap second hand. And to toot my own horn, it looks pretty dang cool. I'll put pictures up if I can.

Chrometuna · Posted: Tue Nov 11, 2008 9:35 pm Post subject: Subject description: Mouser BOM

I think this will be my next project.

I think it might work as good, if not better then the 1v/oct single bus thats been giving me fits.

I went to the Mouser website, and created this BOM:

Someone might want to double-check this.
On some items I doubled the numbers....because I think it's silly too order 1 resistor.....so why not order TWO!? Laughing

Chrometuna · Posted: Sat Nov 15, 2008 3:53 pm Post subject:

OK, I didn't know if I should post this here, or in one of the SL chip substitution threads.

But on the Mini Controller page
It lists an "LF444 Quad Op Amp (do not sub) "

So when it says "Do not sub" can I safely assume that Ray means "Do not sub"?

As though another chip should not be substituted for the LF444? Meaning that no other chip will do?

Well, Mouser does not have a LF444, they just show a "cross match" with the NTE859.
Is this chip going to work?
I went ahead and ordered that chip. So am I screwing myself?

And another question: How different is this actual circuit from the 1v/oct single bus controller?

theshaggyfreak · Joined: Oct 29, 2006 Posts: 48 Location: Centreville, VA

Futurlec has it:

http://www.futurlec.com/cgi-bin/search/qty_price.cgi?part_no=LF444CN

Chrometuna · Posted: Tue Nov 18, 2008 4:38 pm Post subject:

Got it built....but can't get it to work.

The batteries get really hot.
And I have double-checked all of the wiring and so far I can't locate any shorts or miss-wirings. (I DID find a short in the ground wires between the jacks (CV and Gate) and fixed that....the batteries get less hot, but still hot)

When I have ONE battery installed both of the LEDs come on and stay on (I don't think they are supposed to do that?) but if I put BOTH batteries in, then the LEDs do NOT come on. If I put ONE battery in the other clip, the LEDs do NOT come on.

And throughout all of that, the thing doesn't work.

On the power-input side, I used 2 caps that are rated at 100v rather then....uh, whatever. I think they are 10uf. But the voltage rating shouldn't matter, right? Thats just the max amount of voltage those can take before they blow up, right?

I get no LED reaction when touching the 'wand'(BUS) to the resistor chain.

And the gate/CV inputs on the soundlab show no reaction to anything the mini-controller (doesnt) do.

What else should I check and do?

RF · Posted: Tue Nov 18, 2008 7:31 pm Post subject:

If the batteries get hot, I'd be looking for a short, or check your battery harness polarity..

The caps should be fine - be sure you have the polarity correct on those...

good luck ;0

bruce

Chrometuna · Posted: Mon Nov 24, 2008 1:39 pm Post subject:

RF · Posted: Mon Nov 24, 2008 4:52 pm Post subject:

So your batteries are connected like this.... right?

http://www.musicfromouterspace.com/analogsynth/ninevoltsupply.html

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Chrometuna · Posted: Mon Nov 24, 2008 7:57 pm Post subject:

RF · Posted: Mon Nov 24, 2008 8:21 pm Post subject:

OK - just wanted to be sure Smile

I can't think of any reason they would warm up except for a dead short....or nearly so...

Pull the batteries, use your VOM and measure resistance from ground to +,
then from Ground to -,
then and from + to -.

Anything stand out??

Then maybe pull the IC's and do the same measurement... (sockets right?)

There's a place to start anyway...

Chrometuna · Posted: Mon Nov 24, 2008 9:48 pm Post subject:

RF · Posted: Mon Nov 24, 2008 10:38 pm Post subject:

Hang in there Chrometuna - you'll find this.

Ray notes on his pages that it draws 30 ma current at 12 volts....so Ohms law says you should be seeing 400 ohms resistance between the Power supply + or - and ground.... (R=voltage/current)

Check your measurements..... or your meter range selector...

bruce

Chrometuna · Posted: Tue Nov 25, 2008 10:09 am Post subject:

Chrometuna · Posted: Tue Nov 25, 2008 11:38 am Post subject:

Are these caps OK to use?

Are they of a different type then what should be used in these locations?

Capacitor Ceramic(s) .0047uF C25, C24

They are mouser part number:
http://www.mouser.com/Search/Refine.aspx?Keyword=75-125ld47-r

They look very different then what Ray uses in his pic of the populated board. (But these are rated at 250V)

[img]http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=206305379&albumID=1053527&imageID=22491969[/img]

http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=206305379&albumID=1053527&imageID=22491969