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Some notes from the listing on the sound of the DX1 compared to other Yamaha DX synths:
"There will always be people that say that the DX1 is just two DX7s under one roof but having owned four DX1s in my lifetime, (I'm old) multiple DX5s, and DX7s this does not ring true to me. The DX1 has 5 microprocessors and 13 circuit boards inside it's heavy gauge steel body. It was built out of the highest quality components available. It just sounds better in my opinion. I am sure it is in the components used. This entire package is wrapped up in a Brazilian rosewood and heavy gauge steel housing.
I like the first generation of FM synths and how they have a darker more organic sound. If you can't afford a DX1 then get a brown MKI DX7 or a DX5. They all sound fantastic but the DX1 sounds the best to my ears.
I was comparing the sound of the DX5 and DX1 side by side today and the difference in sound is shocking (not just through the headphone amp). When you switch from the DX5 to the DX1 it sounds like someone took a wet blanket off your studio monitors. Also, Being able to program so quickly and use the velocity and after touch as a performance tool makes it special to me and dear to my heart. I have always had a thing for the DX1. I am only selling this because I am moving and have another. It sounds "better" than other FM synths in the same way a guitar or recording console sounds 'better' than another. It is hard to quantify.
Everything on this instrument functions like it should and it looks sharp. It has always been kept in a climate controlled environment. It has two very small cosmetic flaws that are not immediately noticeable but I wanted to mention them. It has a light one inch scratch below the Yamaha logo closest to the keys and a small cosmetic imperfection about the size of a pencil eraser or cigarette butt end on the left hand side. (to the right of the data entry buttons above key #15 on the face of the instrument) Other than those two cosmetic imperfections it looks incredible and would belong in a museum. The inside of the instrument is also extremely clean. It has never been abused or abandoned. Everything on this instrument works perfectly, there are no noisy pots or problem of any kind and I know these machines very well. If you are crazy enough to take this on a tour, every performance would go off without a hitch. It's a very nice machine.
They only made 140 of these. My guess is only 75-100 remain in good functioning condition. It's hard to find a DX1 for sale period, I would say it's even harder to find one in this condition that wasn't set aside to get dusty in some garage somewhere, when all the cheaper and lighter rompler keyboards came around in the early 90s."
"Very early serial number #1001! Maybe the first one made???any experts here. I’ve done some research on how Yamaha stamped their synths back in the 80s…so far no luck. Did they start with 0001 or 1001? [a few have been captured here, all start with 1 or 2]
Some notes from the listing on the sound of the DX1 compared to other Yamaha DX synths:
"There will always be people that say that the DX1 is just two DX7s under one roof but having owned four DX1s in my lifetime, (I'm old) multiple DX5s, and DX7s this does not ring true to me. The DX1 has 5 microprocessors and 13 circuit boards inside it's heavy gauge steel body. It was built out of the highest quality components available. It just sounds better in my opinion. I am sure it is in the components used. This entire package is wrapped up in a Brazilian rosewood and heavy gauge steel housing. 
"Released for only one year, 1998, only a few hundred were sold. A POLYPHONIC synth engine that is unique in the world of sound generation and sound design; a unique sound that can only be found here. Unique Formant + FM sound engine technology that results in staggeringly unique sounds. Nothing else sounds like the FS1R. 
via the seller: "People will go on and on about how the engine of a DX1 is two DX7s. This does not ring true to me. There are so many components and circuit boards inside the DX1 compared to the bare bones set up of a DX7. They may say how a FS1R can do more. This maybe true and they are cool units but the output sounds buzzy and shrill comparatively, plus scrolling through menu after menu is not fun. There is something about the "Rolls Royce" quality of the DX1, plus the sound, plus the interface that makes it really special. This of course is all my opinion. I can say I have compared the sound of the Yamaha DX5 and Mk1 DX-7(sold one of each on ebay and received positive feedback for both) and while they both sound nice the DX1 blows them away in just the weight and warmth of the sound. Comparing a DX1 to other FM synths is like comparing a Fairlight CMI to an Akai sampler. The Akai wins on paper but you don't play paper. Again, all the machines I mentioned are great and have their place. I just think the DX1 is extra special. 
