Casio MT-600 Filter Mods

[DomPallot]

Is there any chance you could please please re upload the documentation as the link is now dead. PLease Thankyou!

[rolandsh1000]

@DomPallot Hi, go to my vanity webpage to get my email address and I will send you the documentation for these mods (see in Description above)

[Qber4life]

This is sick.

[Snaak123]

Hello,

Do you perhaps still have the instructions for this modification?

Thanks in advance!

[rolandsh1000]

@Snaak123 Hi, go to my vanity webpage to get my email address and I will send you the documentation for these mods

[eonz8]

Really nice!!!

The filter and LFO sound great.

[Mikesafilmer]

Wow great job, this sounds amazing. I've been into (controlled) circuit bending lately and I found an almost mint condition Casio MT-800 with it's case and external speakers, and it seems like it has a ton of potential. Have you had any experience with modifying the MT- 800 by any chance?

[mindphlux]

you should make a pedal with those effects :p

[Tyler11440]

what is LFO?

[rolandsh1000]

LFO stands for low frequency oscillator. Basically, it modifies a signal, in this case, the filter cutoff frequency, giving it that 'waw-waw' effect.

[smackyjack]

So.. This really isn't a "bent" circut, but a Filter instalation and LFO installation, Right? I've got a couple of casios I would like to do this with, but you can't bend them. THey are both AC only and have no Battery option. I've just demo'd one of them on youtube here. The Casio 401. I would be interested to learn how to install these things on my Two casios...(or even if you can)

[rolandsh1000]

Pretty much right: not 'bent' but modified. I didn't add the filter chip; it's actually stock in the MT600. I only made the resonance more extreme by changing a resistor, and created external controls for cutoff and res.

I did install an LFO, and used that as a control voltage to alter the filter cutoff.

If there's anything you could say was 'bent' it'd be the switchable caps to the chorus circuit.

Only the HT family and the MT600 have that filter chip, no other Casios. good luck!

[smackyjack]

Yeah, mine are fine the way they are. I think I'm going to leave them alone and not try and improve them.The casios I have are Pro models anyway. These things were marketed as studio gear in 1980 and 1982. The CT 401 is one of the "warmest" little Keyboards I've ever played. The same goes for the CT-7000, but stereo, with stereo effects onboard. I'll be demoing that one next.

[rolandsh1000]

Yeah, I have a CT 602 and a CT 403. I think they have the same sound hardware as some of the smaller Casios, but the build quality, the keys, and larger (and maybe higher quality) installed speakers really improve the experience of playing them. I am often tempted, but just can't seem to modify them, they're nice as they are...

[mikedanous]

1 of the best bends i've heard. You didn't "spoilt" your keyboard, just modified it. And that's what i like.

[themandea]

nice dog!

[youarelackluster]

its wicked to see someone doing filter + modulation modifications. if only people did those for the pt-series..

[becomingzero]

Nice bends. Lots of control and good results. I did similar mods to a ht700 and it's probably more fun to use than my monomachine.

[ssstephenssskates]

i have a casiotone ct-310. will your instructions work for this as well?

[ssstephenssskates]

i love this stuff. you don't have to buy an expensive synth, you can just do this to your casiotone.

[stalag3333]

thats a awesome modified casio. real cool.

[bazziman]

WOW! Could you please post a simple, step by step guide? Any change of modding it so you can tweak the ADSR and other stuff as well?

[synthmonger]

The MN3102's clock can be varied by, i think, using a pot between pins 6 and 7. I did this with my friends yamaha pss-470 that has a similar chip setup (mn3102 and MN3206).

[deltasleep]

I can't really tell from the tones you used, but does this mod eliminate the filter envelope generator entirely, or can you tweak the filter depth on sounds with envelope?

Because that synth bass sound is just too much by itself to ruin the envelope!

[rolandsh1000]

Without opening it up, I've actually forgotten. But I think I kept the filter ADSR intact while taking over the main cutoff control with a pot.

Just now I checked: when I bring up the synthbass preset (you're right: nearly the best thing on this little guy), I do get a clear filter sweep. My added pot just changes the starting point of the filter sweep.

[rolandsh1000]

I read on em411 that your MT600 broke.

what happened to it? Casios are pretty repairable...

[deltasleep]

I played it for a few days. Then one day I went to turn it on, and I get nothing out of it. All the lights operate as normal.

[rolandsh1000]

If the lights go on and respond to keypresses, the microprocessor's probably still alive. I wonder if it's something simple like a dead output amplifier chip. I had a Casio M-10 that went on but made no sound. I opened it up and traced it to a bad 4558 op amp, a 55cent part.

[deltasleep]

How can I talk you into posting a step by step tutorial of this mod? I just got one of these at a garage sale for a buck and i'm blown away at how much better it is than I thought it would be!

[rolandsh1000]

A buck?! Nice!

Regarding a tutorial, if you go to my vanity site page ( see the description in the upper right-hand corner of this page, it has the URL ), it has a lot of the detail up there, but not all of it unfortunately. My email address is there, too, and I'm happy to try to answer some of your questions through private email.

[GreenockRoss]

its chessy about writeing the letters on it

[rolandsh1000]

I agree - those letters on the keys were on there when I got it at the flea market. too much of a pain to remove them...

[lastfirstface]

Very nice mod, thanks for posting. Do you know of any interesting mods for the cz series?

[rolandsh1000]

I remember seeing a website where a guy had bent his CZ101 - the mp3's were pretty glitchy. If you google it you'll probably run across it

[MarsHottentot]

Definitely one of the best mods I've heard!

Circuit Bending isn't all 'bullshit' though (though some is), I've have some amazing circuit bent stuff that is wild, controllable, and most importantly (for reproduction needs) predictable. Ultimately it's a taste thing.

[weatherkop]

That is some proper modding. I hope to learn those techniques and apply them to my mt240, or even my ht700 since it already has a filter. I love pots.

[electricpony]

This is some of the best circuit bending work i've ever seen. I actually just picked up one of these keyboards on ebay and will hopefully be able to try some of these out. Do you have any samples of the filters being applied to the keyboard's other tones or the accompaniment parts?

[rolandsh1000]

I know of your ebay purchase - you outbid me! ;)

Thanks for the compliment.  To address your direct question: I don't really like Casio accompaniments so I didn't run them through the filter. The drums are OK on the MT600, but since they're not truly programmable, I didn't run them through either. So - sorry - but no samples of them.

If you go to the webpage listed in my comments section, my email is there - I'm happy to answer questions that way, too.

[electricpony]

Thanks, I appreciate it!

[1devo6587]

SO WHAT IS A LFO AND HOW DO I GET ONE AND CAN I INSTALL IT ON MY Casio MT 140 AND MY Casio MT 68 OR ANY Casio MT MODELS?

[freezazoid]

finally a good casio mod, not just the same old 'circuit bent' bullshit that sounds like a bunch of noise. this is actually a useful mod. is it hard to do?

[rolandsh1000]

thanks!

it's too bad Casio didn't use this great filterchip in more of their keyboards (the whole HT family has 'em, though).

the mod itself is probably 'medium' difficulty: I had to figure out the correct voltages to run into that chip, and I did have to add my own LFO, but I've seen circuit bent stuff that used a LOT more hardware...

[zoomckng]

way cool man

[notjason]

That's incredible.

[victorcab]

Is that your assistant in the background?