It is not surprising that Brian Eno likes the Casio 202.
(These toys including MT-100, MT-65, etc have a sampling rate of 600KHz!!!
http://www.firstpr.com.au/rwi/casio/Casio-931-2006-06-17.txt)
This can be seen in the interviews, The Life of Brian - Electronic Soundmaker and Computer Music
http://music.hyperreal.org/artists/brian_eno/interviews/escm84.html
It has nice sounds. And it seems that Casio is having the octaves a bit more that x2 in frequency so they sound correct to ear-brain. (Frequency and pitch is not the same but they are related). Frequency is the objective quantity, pitch is the subjective. Pitch also depends on intensity (ref. S.S.Stevens - Sound and Hearing or Stevens and Davies - Hearing).
It seems the MT-100 as tested does the same octave "stretching" and so the MT-65 should do.
Do they all have the same principle of sound creation? Possibly yes. Are they using Walsh functions synthesis? It seems the overtones sound correct too to ear-brain. Do they also have relations a bit more than an integer multiple like Streinway pianos do? Are Stradivarius violins the same in terms of "stretched" overtones?
Is Brain Eno driving an Eventide H3000 with his Casio 202? Another reason why an Eventude sounds great with an electric guitar is that when the strings are stetched more (ie more than 440Hz or thicker strings) the overtones are progressively higher than just x2 which is what is needed!
More on incorrect stretched octaves so that they sound correct to human can be found on earlier euroelectron posts with references.
Does the Casio CZ series use deliberately "wrong " ie correct octaves? By listening on YouTube to CZ101 it seems yes.
It would nice to reprogram the micro controller of Roland Juno 6, and other Juno series to make the octaves wrong ie correct.
Some older analog synthesizers get away with it by having inter sly or externally adjustable volts per octave so that they can be adjusted to sound correct ie more than doubling of frequency which sounds ridiculously flat.
Fortunately synths like the Yamaha DX7ii and Korg Triton have all note user defined scales.
Please read also Pleiades tuning for DX7 and Korg Triton on earlier euroelectron posts.
