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the19thbear
Joined: Apr 19, 2007 Posts: 150 Location: denmark
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Posted: Fri Aug 09, 2013 10:22 am Post subject:
Making a midi keyboard shorter |
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Hi. Basically I want to make a midi keyboard i have, shorter by one octave.
I have the row of contacts here, with all the diodes etc. How should i go about making it shorter? In a perfect would, i would be able just to cut the circuit board shorter, end of story. But im guessing i'll end up with some keys not working..
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seraph
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Joined: Jun 21, 2003 Posts: 12398 Location: Firenze, Italy
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Posted: Sat Aug 10, 2013 2:56 am Post subject:
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what about selling the one you have and buy a shorter one?
_________________ homepage - blog - forum - youtube
Quote: | Don't die with your music still in you - Wayne Dyer |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
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Posted: Sat Aug 10, 2013 8:37 am Post subject:
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I agree with seraph, it won't be a simple job to just slice the keyboard.
The designers of those boards do not take into consideration such modifications, so circuitry placement would be fairly abitrary from that standpoint.
If you don't have the schematic and all of the required skills to restore all necessary circuit paths, then this would be a very risky adventure likely to end in failure. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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Cynosure
Site Admin
Joined: Dec 11, 2010 Posts: 966 Location: Toronto, Ontario - Canada
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Posted: Sat Aug 10, 2013 9:53 am Post subject:
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This is the first time I ever heard of someone wanting a shorter keyboard.
Like JovianPyx said - if you cut a required trace on the PCB then you could screw it up.
However, if you carefully follow the traces on the end that you are removing and see that the only place that they are going is to the key switches, then it might be ok. Most scanning circuits will be checking for a closed circuit from the key switch, so removing it would just make it permanently open.
A service manual would help you identify the traces and if it is possible to only remove the desired keys. What is the make and model of the keyboard?
I am curious - why do you want less keys? _________________ JacobWatters.com |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24085 Location: The Netherlands, Enschede
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Posted: Sat Aug 10, 2013 12:30 pm Post subject:
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Hmm .. well .. there was this person before wanting to cut a Nord Lead in two .. eventually that led to the .. what was it !v chat command? ... (recently i cut my X in half .. oh my ex eh :¬| ).
Apart from that - if you'd want to shorten it you would want to know where all the PCB traces go and what hey are good for; as you already said some other keys may stop working. Probably the keys are put into a scan matrix - so there will be row and column lines, cutting one wrong track may cut an entire set of keys further on on the keyboard, or key on would still work but velocity would not work anymore, stuff like that.
Anyway, when you decide to go on anyway - good luck, and keep us posted :¬) _________________ Jan
also .. could someone please turn down the thermostat a bit.
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bubzy
Joined: Oct 27, 2010 Posts: 594 Location: United Kingdom
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PHOBoS
Joined: Jan 14, 2010 Posts: 5609 Location: Moon Base
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
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Posted: Sat Aug 10, 2013 10:16 pm Post subject:
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If the keyboard has a standard diode matrix, then it's fairly easy to cut down - as long as the matrix PCB is logically laid out (most of them are), and usually only from the top octaves down.
Each key has a pair of associated diodes (note and velocity), so you'll need to find the pair for the last note you need. You can then cut the PCB from that point as well as the keybed.
It can be done, I've recently cut down two CME M-Keys from 49 (4 octaves) to 37 (3 octaves). |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
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Posted: Sun Aug 11, 2013 5:51 am Post subject:
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AndyR1960 wrote: | It can be done, I've recently cut down two CME M-Keys from 49 (4 octaves) to 37 (3 octaves). |
This is insane.
I might cut a 4-octave down to 44 keys or a 5-octave down to 56 keys, but never remove a full octave.
Ugh. 3-octave keyboards are esthetically offensive and just plain irritating. Reminds me of the old cheesy blower-driven "Chord" Organs. _________________ Revenge is a dish best served with a fork... to the eye |
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bubzy
Joined: Oct 27, 2010 Posts: 594 Location: United Kingdom
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
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Posted: Sun Aug 11, 2013 9:05 am Post subject:
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richardc64 wrote: |
Ugh. 3-octave keyboards are esthetically offensive and just plain irritating. Reminds me of the old cheesy blower-driven "Chord" Organs. |
Never did an ARP Odyssey any harm |
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the19thbear
Joined: Apr 19, 2007 Posts: 150 Location: denmark
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Posted: Sun Aug 11, 2013 10:36 am Post subject:
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well whatayanohw - Its not needed anymore - but thanks for all the suggestions and smart remarks - I'll end up using the full range, but put pitchbend/mod wheel somehwere else in my design so i actually have room for the whole keyboard..
thanks again! |
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Manuel Marino
Joined: Aug 07, 2013 Posts: 15 Location: Italy
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Posted: Tue Aug 13, 2013 7:14 am Post subject:
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why cutting a keyboard? honestly, what's the reason? use it in clubs while playing dance music?
bring it in your favourite sack while doing a travel around the world?
or simply, removing the octave that doesn't work anymore after years of playing? _________________ Listen to Free Samples from my soundtracks or read Guitar, Bass, Piano and Drums Lessons and News from my Homepage. |
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the19thbear
Joined: Apr 19, 2007 Posts: 150 Location: denmark
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Manuel Marino
Joined: Aug 07, 2013 Posts: 15 Location: Italy
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