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 Forum index » DIY Hardware and Software » Musical Interfaces
Keyboard for DIY synth?
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TreDiggy



Joined: Jan 04, 2012
Posts: 3
Location: Greenville S.C.

PostPosted: Wed Jan 04, 2012 11:24 am    Post subject:  Keyboard for DIY synth?
Subject description: What keyboard should I look to salvage for a DIY synth I plan to build?
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I'm very new to synth building and I was wondering what kind of keyboard should I look to salvage for an analog synth I was planning to build? Would a cheap Yamaha keyboard work or should I look for a organ? If you have any links to videos that would be great. Evil or Very Mad
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efabric



Joined: Jan 05, 2012
Posts: 19
Location: Caen, France

PostPosted: Thu Jan 05, 2012 4:08 am    Post subject: Reply with quote  Mark this post and the followings unread

You can check for the yamaha YK-10/20 keyboard for cx5m fm synth computer. It contains resistor ladder instead of diode matrix. Easyer to modify.
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Cynosure



Joined: Dec 11, 2010
Posts: 623
Location: Toronto, Ontario - Canada
Audio files: 34

PostPosted: Thu Jan 05, 2012 8:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

Oh really? I got one of this sitting here that I have been waiting to open and modify when I start my modular synth. Thanks for the info!
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efabric



Joined: Jan 05, 2012
Posts: 19
Location: Caen, France

PostPosted: Fri Jan 06, 2012 1:20 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm sure I've seen a lot of identical resistors... but I don't have this keyboard anymore. It may have a diode / resistor mix inside the keyboard (for note polyphony and mono velocity ? ) can you check inside ?
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Cynosure



Joined: Dec 11, 2010
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PostPosted: Fri Jan 06, 2012 9:06 pm    Post subject: Reply with quote  Mark this post and the followings unread

Just diodes.

If anyone has any experience or advice for turning something like this into a CV controller then please let me know if there is a write up, video or thread floating around somewhere. I don't plan on getting to it anytime soon, but it would be nice to have some notes from someone who did it for when I do get around to doing it.
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agreyspark



Joined: May 02, 2012
Posts: 4
Location: England

PostPosted: Fri Dec 14, 2012 4:01 am    Post subject: Reply with quote  Mark this post and the followings unread

Is it still possible to buy bare keyboards for DIY?

I know you could get them back in the 80s where there were plenty of projects in electronics magazines, but I can't find a supplier these days
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Cynosure



Joined: Dec 11, 2010
Posts: 623
Location: Toronto, Ontario - Canada
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PostPosted: Fri Dec 14, 2012 6:15 am    Post subject: Reply with quote  Mark this post and the followings unread

http://www.fatar.com/
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richardc64



Joined: Jun 01, 2006
Posts: 609
Location: NYC
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PostPosted: Sun Dec 16, 2012 6:32 am    Post subject: Reply with quote  Mark this post and the followings unread

Written against my better judgment...

All matrix KBs will have a diode for each switch. Clip out the diodes or *cut the ends that connect to each switch, bend the diodes up, and solder the resistors of your "string" to the stubs. Wire all the groups of switches together and that becomes the single buss.

There are at least two variations of where the diodes are located in relation to the switches;Attached I show both. The method of alteration will be the same. The "groups" might be of eight keys, 12(+1) for octaves, or six(+1) for half-octaves. Yamaha and Casio are (in)famous for devising odd-ball groupings. Fatar's 2-switch per key (make and break,) KBs will be a little more trouble. Clipping/cutting should be done at the "make" switches.

Good luck dealing with any switch resistance.

By no means is all this intended to be an endorsement of finicky, resistor string voltage divider and droopy sample & hold single-buss designs.


*This way, the diodes can someday, when you've realized the error of your ways, be soldered back for a scanning design - which, btw, doesn't have to be interfaced with a microcontroller.
http://www.musicfromouterspace.com/analogsynth_new/OLDIESBUTGOODIES/CONTROLLERS/scanningmatrixkeyboard2.html

I don't understand why Ray has made this design harder to find.


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Diodes will be reversed in KBs in which a pressed key causes a logic 0.
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agreyspark



Joined: May 02, 2012
Posts: 4
Location: England

PostPosted: Mon Dec 17, 2012 3:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Cynosure wrote:
http://www.fatar.com/


thanks,

I followed a few links and came to a supplier in the UK:

http://www.keyparts.co.uk/shop
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Dragon's Lair



Joined: Dec 29, 2006
Posts: 185
Location: Nakusp BC, Canada
Audio files: 1

PostPosted: Mon Dec 17, 2012 11:23 am    Post subject: Reply with quote  Mark this post and the followings unread

I happen to like my finicky, resistor string voltage divider and droopy sample & hold single-buss keyboards, of which none are finicky or have droopy sample and holds, once they are tuned and scaled, they stay that way.
Actually, most cv keyboards are dual buss, one for CV and one for the Gate, (my ribbon controller design is a single buss, and it works fine) which is why these cheap Fatar keyboards are perfect for conversion.
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Rolbista



Joined: Nov 17, 2012
Posts: 20
Location: Poland

PostPosted: Thu Dec 20, 2012 2:56 pm    Post subject: cv/gate Reply with quote  Mark this post and the followings unread

hello, I figured I'd ask in this thread instead of making new one. I'd like to add primitive CV/gate output to my little Casio keyboard for controlling the filter and gating the ADSR module. Do you have any tips on how to add switches activating CV and Gate to an existing keyboard? Microswitch on each key? The circuit would be separate from the Casio, only the keys would be common.
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