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Author Topic: Pitch Bending Keyboard With Crystal Timer  (Read 1012 times)

SamVsSound

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Pitch Bending Keyboard With Crystal Timer
« on: March 07, 2017, 10:41:01 PM »

Hi Guys

I was hoping you could give me some direction, I am currently playing around with a keyboard (cheap Discovery Kids keyboard) which uses a crystal oscillator for the pitch/clock control

The crystal on board is about 14 MHz (14.13181)

I am looking for a variable oscillator option to replace this crystal. At the very top end of the 555 range I can get the bottom end of the keyboards operating frequency (I believe 555 tops out around 500 KHZ) but it is no where near capable of the high frequencies necessary to drive the keyboard effectively.

Most of the transistor based oscillators I am aware of cannot be adjusted via a pot so I could use them for a static pitch switch but not a variable one.

I know the LTC1799 is an obvious choice but Get LoFi is currently sold out of both their breakout boards and kits. As far as I know this chip is not available as a DIP chip and I am not really set up to work with SMDs. Also since this is a fairly cheap keyboard and I'm not sure what else I'll be able to get up to in it I would prefer to build something with parts I have on hand rather than paying for and waiting for a specialized chip. At least initially until I see how far it goes.

Any suggestions or schematics you guys could recommend would be greatly appreciated

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DIY Synths and Electronic Oddities

davelybob

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Re: Pitch Bending Keyboard With Crystal Timer
« Reply #1 on: March 16, 2017, 07:48:32 PM »

You can get them right here, but broham is in UK so factor that shipping in.  I've always got them from Getlofi since I'm also stateside, but I've gotten so much advice from dude, my next batch purchased will probably be from here anyway just out of appreciation.

https://www.circuitbenders.co.uk/forsale/LTC/LTC.html
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SamVsSound

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Re: Pitch Bending Keyboard With Crystal Timer
« Reply #2 on: March 30, 2017, 05:49:11 PM »

Nice, yeah i'm over in Canada but the shipping seems fairly reasonable. I'd also like to support these guys as their site has been a huge source of inspiration and advice. I'll probably wait until I can justify ordering a large batch but I'll get them here :)

Since posting this I picked up a PSR-6 which also uses a crystal timer so I'll need at least two and I'm sure these two will not be the last keyboards I mess with so I figure the more I can grab the better.

Thanks for the heads up
« Last Edit: March 30, 2017, 05:51:07 PM by SamVsSound »
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Build documentation and tutorials available at:

www.SamVsSound.com
DIY Synths and Electronic Oddities