Btw, the M500 "Micropreset" doesn't belong to that family:
The 700, 700S, 770, 800DV, 900PS, SyntheBass and PE 1000 have the famous LP & HP serial "Diod filters", while the M500 has the same "KORG35" integrated LP filter than the MS10, X-911 & MS20 MkI.
Anybody know the differences between the 770 and the 700S?
Do you see the black square blocks in the open synth picture posted by Jexus?
Those are prehistoric integrated modules (VCOs, VCFs, EGs, VCAs): In fact, all discrete circuitry hidden in a plastic black box, to defeat industrial spying.
Well, the VCAs are different, so the sound isn't excatly the same...
Korg MS20-MS50-SQ10-X911-SuperDelta-800DV-MP4-Lambda ES50-severely modded Poly800-PE1000-M500SP-Trident MkII-KPR77-DSS1-P61//EkoSynth P15//YAMAHA CS30-CP30-DX9-01V//RSF Blackbox x2//Viscount CL1-R64//SCI Multitrack-P600//Roland GR500-SH1000