CASIO MT-205...

matriv · August 11, 2008, 07:53:23 PM

Hi, I'm a pretty inexperienced tinkerer. Just got a casio mt-205 with the dp-1 drum pads.
I'd really like to try and bend the keyboard, paticularly the drum noises. Has anyone had any experience
with this keyboard. Or just general tips for bending this era casiotone??
I would be very grateful
cheers,
Mat

AttDestroyers · August 12, 2008, 05:54:05 AM

yeah, I bent mine, there's a couple good drum glitches... poke around, add components, etc...

matriv · August 12, 2008, 04:35:56 PM

cool, good to know it's possible, haven't been able to find much about it online...

James · August 18, 2008, 06:40:12 PM

I'm currently working on a MT-220, but this applies to the MT-205 as well...
You can get some nice drum mods by disconnecting the clock input to the drum chip and building another variable frequency one with a 7414 instead. You can vary the sample playback rate of the drums and control their pitch. It's sounds good pitched up, but pitching down gets nice and messy as the samples break up.

James

matriv · September 04, 2008, 05:27:45 PM

Hi James. sorry I'm pretty ignorant about this. What's a 7414? I kind of get what you are implying, could post any pictures or just any more information for a complete novice. So far I've just stuck a couple of switches on. One puts some lofi type distortion on the drums and the other mangles the demo chords. For some reason you might be able to identify the frequency of the distortion varies depending what voice is selected. ie. funky clav makes the drums trebley and harsh whereas piano makes them kind of muffled. A happy accident...

computer at sea · September 05, 2008, 03:13:56 PM

A 7414 is a chip. It basically has the makings of 6 oscillators on it. There's some great information about building oscillators using a 40106 (which is pretty much the same as a 7414 but can handle more voltage without cooking) over here: http://fluxmonkey.com/electronoize/40106Oscillator.htm

The oscillator then would provide the keyboard with a new adjustable clock signal to control the pitch of the drums.

I highly recommend picking up a few 40106's and just fussing around with them. Even if you don't end up building them into bending projects, you can make some nice sound machines with them. Here's a link to a video of one of mine: http://fr.youtube.com/watch?v=cttZX41jwgI

The great thing is, you really don't need to understand why or how it works to start experimenting with the 7414 or 40106 chip.

matriv · September 07, 2008, 07:37:22 PM

Thank you! that's really useful

shimshon · September 23, 2008, 02:15:34 PM

hey matriv,

i've bent an mt-205. i got it at a flea market and loved the drum slide switches. looks like there are a few nice bends in this thing...

the most extensive bend i found was shorting the pins on what is probably the drum chip. i'm not sure since it's on the other side of the board and i just soldered to the pins of it, but if you're looking at the mt-205 board from the side of the keys, you'll see a surface-mounted chip - mine says something like "HD617....". to the right of that is a series of 12 aligned pins parallel to another series of 12 pins. shorting those pins will give some weird drum glitches, and also some not-too-exciting keyboard glitches.
i created a patch bay for that bend using RCA jacks, and put a female serial jack on the keyboard and a male serial plug on the patch bay, to make it detachable.

found a couple other bends as well... two that give really raunchy distortion when you play keys while the keyboard is in "fingered" or "chord" mode.

found four bend spots that'll repeat a note over and over - when you engage more than one at a time it speeds up the repetitions.

and a couple other drum glitches that aren't very exciting.

i'd be interested in trying the distortion for the drums, do you know which components you connected?

if you can upload a picture of the PC board, i'll map out the bends that i mentioned. my board is too cluttered with wires to use as a map, can't see a lot of the pins. would appreciate it if you and AttDestroyers posted your mods as well...

-vito

matriv · September 25, 2008, 03:46:49 PM

hi, I'll try and get some photos uploaded soon. I'd be interested in trying the drum glitch bends. I think I found the same raunchy distortion you speak of. The drum distortion I found is quite a similar bend, possibly from one of the same points even. Sorry I'm not with the keyboard at the moment so I can't verify. Will get back to you asap.
Cheers,
Mat

Gleix · October 16, 2008, 05:59:43 AM

Quote from: shimshon on September 23, 2008, 02:15:34 PM
if you can upload a picture of the PC board, i'll map out the bends that i mentioned. my board is too cluttered with wires to use as a map, can't see a lot of the pins. would appreciate it if you and AttDestroyers posted your mods as well...

-vito

Picked up an MT-205 at a flea market last weekend. I'll take you up on that offer if you're still interested

http://i37.tinypic.com/35n58cg.png Here's the board (two pictures for detail)

All the pieces are in the background since I'm washing the plastic... flea market keyboards are so dirty :/

shimshon · October 21, 2008, 03:52:24 AM

Quote from: breakbeatnazi on October 16, 2008, 05:59:43 AM

All the pieces are in the background since I'm washing the plastic... flea market keyboards are so dirty :/

i know what you mean... you see that foam surrounding some of the wires? when i opened mine up all that shit was disintegrated and got all over. also a flea market buy...

i'll take a look at the bend points as soon as i've got some time. my girlfriend is actually jammin out on my 205 and bent alesis sr-16 right now and it's sounding awesome