Yes, it was Russell Ferrante, the pianist who played on both Talk to Your Daughter and Revelation, and both cuts used the GS1. That's the guy I quoted remarking about the GS he played and how no other synth could do it.

The opening bars of both recordings have a virtually identical EP sound.

I had forgotten that Chick used it on Ginkakuji with Eddie Gomez. When I saw him perform it live in the late 80's with his Electrik Band Trio, he had a rack of at least two TX816's controlled by his MIDI-fied Rhodes stage and had a Synclavier for good measure. At the time, it was pure ear candy with that high end FM and Pattitucci and Weckl providing a rhythmic space for Chick to paint on an open palette. All of the brass and strings came from the Synclavier. There is a another really nice piece on the CD of this band, "All Love" that is a good example of him mixing the Rhodes, TX and Strings. Ginkakuji (Silver Temple) is the last cut and is just superb!

https://www.youtube.com/watch?v=_qMRnTG0P3g

Russel F. played a Hammond on some live cut of one of the two tunes you mentioned. Something in that vein but still FM would be "FM Rock Organ 4" with the mod wheel rolled back (127) and Assignable Switch 1 button turned ON.

There are other interesting FM organs in there - this one reminds me most of the transistor organ with built-in Leslie (a Thomas Organ - not the Lawrence Welk edition - but I had one a few notches down).

Actually, my favorite part of that organ was the analog section. I thought there was something wrong - all the "horrible" drift and approximate notes. Then I heard Alice Coltrane play on a recording what must have been similar circuitry - further away from the "expiration date" (closer to the production date) - with the same wonky sound. It certainly does do the "wall of sound" kind of stuff well when you can plaster the walls with all kinds of microtonal phrases.

If you have a link to a recording of the AC organ example, I'd love to hear it.

By the way, I can almost replicate the "filter opening/closing" effect on the EP at the very end of YJ's Revelation.

I assigned aftertouch to one of the modulation operator's output level with a very shallow ramp response curve (you only want to open the high frequencies part way). So when you sustain the EP and dig in/out with aftertouch, it opens and closes the high frequency content. I need to add more sustain to the ADSR, though since the effect dies off rather quickly. A dedicated FC would also be an option to control it.

This is an amazing instrument!!

I'm not sure if it was organ or not. It was an analog synth of some sort. The Thomas organ had a section of sounds that were outside of the organ stops. I think along the top or maybe near the rhythm machine thing were a series of buttons that allowed dialing in "synth" kind of sounds. Spacey stuff. Although I'm sure some were called flute and bassoon and what not like the organ. These were all monophonic. The AC cut - or part I was alluding to - may not have been an organ - but something with these analog sounds and similar.

I did try to dig up a youtube link a while back for the recording but couldn't find it. It was a Hastings used bin find probably 20 years ago or so. I still have the CDs indexed in binders - just need to thumb through the piano books. At least I'll better know the target name of the album for a youtube search.

Got my CD book out and this is the album:

https://www.youtube.com/watch?v=I6pPlK6X59c

I spot checked some tunes and the sound of the analog synth in the recording is much more stable than I remember. Perhaps there are times in the recording if listening to the entire album that the synth drifts or is made to sound less stable. The organ I have when using the monophonic "synth" sounds is a real moving target and not as stable as some of what I heard in just clicking on random parts of the album. Kind of amazing what you can find online, though. This is a 2 CD set I'm guessing all documented here.

I can listen to the CDs instead to see if there's anything different that may be an "out take" on my CD set - not on Youtube - and better demonstrates what I was remembering from listening to this album last probably around 1998.

EDIT: I think the youtube selection has all the same that I have on these two CDs. Each with about 30min of music per CD.

Hard for me to tell the organ just from the side and shape of the front supporting leg. But does sound a lot like the Thomas analog sounds in character. Thomas combined Moog in their organs at one time (not in my Organ) as well as licensing the full Leslie name - so an interesting piece of "kit" in some of those organs.

Kind of veering off center here from the GS1 discussion. But to bring it back slightly at least into the Montage realm:

The analog drift I sometimes simulate using a motion sequence. LFOs can work for this as well. Even envelope follower with the destination as pitch works - as you can output "random" sound mass out an internal-only routed "channel" (PART) and this can be used to offset pitch.

This isn't really related to the GS1 - but at least back to Yamaha.

Although this topic is a year old, I'd like to contribute some technical info to the discussion. My familiarity is with the GS2 of which the GS1 shares the identical FM circuitry (times 2). I have no experience with Montage or FM7, FM8.

The block diagram floating around the web showing the GS algorithm is correct, but not complete. It's missing the feedback loops on the modulators. I've attached an updated version. Each modulator can be programmed independently for one mode of operation:
1) normal FM
2) self-feedback Pi
3) self-feedback Pi/2
4) cross modulation (nesting)

Cross modulation is used to 'stack' two modulators on top of a single carrier. In DX7 terminology, it's a stack of 3 operators. The top modulator can have it's own Pi (or Pi/2) feedback switched ON (or OFF) or, have it's own cross modulation switched ON (or OFF). With all this programmability, there are many 'algorithms' to choose from.

With regard to the 'E Piano' sound, GS1/GS2 has many piano sounds (Electric, Electronic, Acoustic, Honky Tonk, and Funk). For the most part, piano sound modulators are programmed as 1 and 2 from above list. The closest sounding patch to the E piano sound taken from Yellowjacket 'Revelation' song, is called Electronic Piano VII (1, 1 above). This has the 'swirly' sound implemented with detuning of both modulators and one carrier. The second carrier is not detuned. No 'ensemble' effect is added to get the swirly sound.

To my ear, the intro to Revelation song has the piano sound of a Rhodes with the Dyno-My-Piano modification. And watching a few early video's of Yellowjacket, he's playing a Rhodes. The end of Revelation has the sound of a B3 organ thru a Leslie. For sure, the GS1/GS2 closely emulates that sound with the ensemble effect turned ON.

Hope this adds to the discussion in a constructive way.

It would certainly be great if one or more of the developers could be interviewed sometime in the future!

Please have a look at the links below:

Inteview with Dr. Chowning the Father of FM

Basics of FM Synthesis by Dr. Manny Fernandez one the world's best FM programmers. Complete series of articles and downloads follows.

Behind the Synth -Scott Plunkett One of Yamaha's top programmers