The SY35 is a synthesizer manufactured by Yamaha in the mid 1990s. It was one of Yamaha's hybrid synths (like the SY77 and SY99) using both FM synthesis and AWM (Advanced Wave Memory, Yamaha-speak for sample playback) synthesis.
THe SY35 was an improved version of the SY22/TG33 the main differences being that the SY35 used 16 bit samples as opposed the the 12 bit samples used in the SY22 and TG33, more sample ROM and thus better sounding samples, minor OS updates, and a much better keyboard then the SY22. (The TG33 was a module)
The SY35 used vector synthesis which they acquired from Sequential Circuits after their demise. The OS allowed either two (one FM and one AWM) or four (two of each) elements (another Yamahaism) per patch each of which was assigned a NSEW direction and could have its level and/or detuning relative to the other elements modified either automaticly by the synth of manually by the use of the vector joystick.
In addition to this the SY35 has the usual stuff you'd expect from a synth (ADSR envelope, LFO, etc. one per element). The one notable ommision is the lack of filters. Although filter effects can be done in FM this still doesn't let you filter the samples.
I have no idea what they were thinking when they decided not to include filters and if anybody can tell me the reason why please let me know.
There are 128 AWM samples to choose from and 256 FM "waves". They are not really waves but preprogramed FM voices. You see, in order to simplify the OS they decided not to allow access to all of the FM parameters from the front panel (or maybe they reallized that FM programming is insanely hard). However all of the parameters are accessable
via MIDI sysex and there is a program called SY-Edit designed just for the SY35 and its predecessors.
The FM elements are each four operator synths with 8 selectable algorithms (basicly each FM element is a DX9 (or DX11, I'm not exactly sure) engine). Though this is not as versatile (or complicated) as the DX7 it still allow some excellent sounds to be created.
It features a 61 key velocity and aftertouch keyboard, 64 preset patches and 64 user programmable patches (an additional 64 or 128 patch locations are available with a memory card), 16 voice polyphony and 8 part multitimbrality.