Casiotone CT-101 Mods

[@CaleAnderson]

Hey are you still around, Aidan? I really enjoyed this showcase. You’re such a legend for this 🎉🎉

[@looseburdens4259]

That was really cool, totally transforms the instrument

[@darwiniandude]

Very cool! Glad I found this video. I've found that PDF with info on the mods you mentioned, and downloaded it. I have this keyboard with the incorrect volume pot in it. Growing up we had this keyboard and an upright piano. I knocked over the casio and the knob broke off. I was in primary school and put a different knob in, but didn't know various potentiometers had different values, or linear vs log. I'll fix that some time. Anyway my brother had it for many years, then at one point asked if i wanted it back, or he'd throw it out. Yes! So I have it again. Love those repeating sounds too, I agree.

[@darwiniandude]

Oh, one thing this has going for it of course is plenty of polyphony. Not everything back then had that.

[@aidanpetersen8425]

That sounds great! Unfortunately I can hear mine slowly dying:( (gets crackly and sometimes has loud pops) it probably needs all its capacitors replaced. Guess these instruments have an expiration date with it being over 40 years old now. These are great instruments tho - glad to add another video of one to the KZbin space :)

[@splegle]

is there any chance you could upload a tutorial on the vibrato speed mod? ive been wanting to do that to mine for a while but i have no clue how

[@aidanpetersen8425]

Yo! Yea - I'll cook something up for ya! Although it might be best checking the documentation from Robin Whittle (in the previous comment's response). For the vibrato *speed*, it's really just bridging some pins on the IC with a diode (I used an LED lol). Then you can use a SPST switch to activate and deactivate said diode, and voila. The vibrato *depth* control is a bit more complicated; it uses a SPDT and requires some cutting of internal wires (scary).

[@splegle]

@@aidanpetersen8425 heard! i’ll def look into that thank you!

[@aidanpetersen8425]

kzbin.info/www/bejne/fmnCkGp_ds51Y6Mfeature=shared Here you go! @@splegle

[@aidanpetersen8425]

kzbin.infoyDH5j4AaTp8?feature=shared Here’s me playing some Zelda on it :)

[@Charleshowes23]

Do you know where I can find the PDF for these mods?

[@aidanpetersen8425]

Yes, Robin Whittle made the guide: static.miraheze.org/circuitbendingwiki/2/24/Casio_Mod_Guide_.pdf Although please as always don't try at home, especially with a wall-AC connected unit like mine. His guide was based upon the smaller battery powered models. But I did a bit of trial and error with my larger model and found all the circuit bending points, and the rest of the mods I just figured out myself!

[@Charleshowes23]

@@aidanpetersen8425 Thank you! I forgot that I had that file on my phone, and didn’t realize it covered the CT-101! Thank you!!

[@Charleshowes23]

@@aidanpetersen8425 Thank you again for your reply. Do you know if the 101 is close to the 201? Did you add any circuitry besides switches and pots?

[@aidanpetersen8425]

@@Charleshowes23 Hiya, so the 101 isn't really similar to the 201. They use the same synthesis method, dubbed "vocal-formant" synthesis, but Casio as being a huge electronics company - they put virtually the entire circuitry for the unit on a single IC. Similar to how they make their quartz watches. I mean, it's clear if you imagine similar synthesizers in the 1980s comparatively to other units. I've seen the internals of monophonic analogue synths, as well as larger digital synths like the DX7 and they're much much more complicated. So because Casio synths are built in this integrated fashion, it essentially means that there's little modding that can be done outside of mods to keyboards with similar main IC's. And as the 201 and 101 have different architecture IC's - any mods from one are not really applicable to the other. Check out Simon The Magpie tho, as he may have done a 201 mod to my recollection, but I don't really remember. Also I'm not sure what you mean by your last question, but feel free to watch my other casio 101 video on the channel where I show the internals of the mods! Hope this helps.

[@abrakadeep8810]

Do you think any more interesting and more brutal mods / bends are possible on it ? I can really find any resources other then your video where people fiddled with this machine :)

[@aidanpetersen8425]

Possibly! the truth is there's just so little documentation as you say... Robin Whittle: "[The] CT-101 has a sinusoidal clock signal" (as opposed to a traditional square wave), so under/overclocking would require building a separate unique clock. I have noticed that the potentiometer on the rear of the keyboard does affect the pitch of clock noise - so you could possibly use a Vactrol to vary this, and get a voltage controlled pitch control. But this would only be useful for some basic FM / vibrato which the keyboard already has. Of course you would need an external CV source for this, so I chose to ignore attempting a 'mod' such as this. Additionally, you could find audio path points, and put passive effects in line - such as diodes for distortion or a transformer for octave fuzz (Black Ice, Green Ringer, etc). The reason I didn't do these was because the audio-signal voltage internally is so high, and I'm not sure if these guitar level effects would work safely or with stability. Lastly, typical in the circuit bending community you have folks putting switches and potentiometers on random points on the PCB, to see if you get any cool effects like you say - which you should DEFFO not do with this keyboard as it has live 230v (or 120v) AC, let alone that you risk breaking your keyboard obv. Even opening it is very dangerous and would not recommend given its age and old capacitors - there's a video on KZbin of the CT-101's sister model, the CT-403 catching fire :/. kzbin.info/www/bejne/aqSzlaZqlLWDmZo&ab_channel=Gearfacts For a slightly safer alternative, I believe the MT-60 is a battery powered unit that utilises the same DG-990* IC chip as the CT-101 tho. Here's the guide by Robin Whittle: www.firstpr.com.au/rwi/casio/casio-mod-01.pdf I believe on other units, Simon the Magpie (www.youtube.com/@SimonTheMagpie) does some great vids, as well as Keen on Keys (www.youtube.com/@KeenOnKeys). Hope this helps :)