Early Seventies Synths

I'm doing a bit of research into pre-1975 synthesisers for a project. These are all on the bay today:

ARP Pro Soloist, preset monosynth from 1972, up for £450, uk

EML Electrocomp 101, semi-modular system from 1972, up for £2K-ish, uk / usa

EML 400 / 401 dual vco synth and sequencer, 1972? £1600 greece

EML Electrocomp 500 monosynth, 1973, currently $1200, us

Korg 700s preset monosynth from 1974, £525, us

Korg 900ps preset monosynth, 1975, £500, poland

Roland SH3, their first non-preset monoynth, from 1974, £1000, germany

Roland SH1000 preset mono from 1973, they go for around £200

Roland System 100, part of a semi-modular system, 1975, around £1000

Yamaha SY1 preset monosynth, 1974, around £200-300

I got all the dates from Peter Forrest' A-Z of Analog Synthesisers