Hey John, thank you for posting this,
seems like soundtechniques schematics are impossible to find, but for me is the holy grail of all the mixers, I think that a good 40% of all my favourite records were cut through the Sound Techinques A-range: Nick Drake albums, Lou Reed Transformer, Led Zeppelin IV, The Beatles Hey Jude, The Doors, Space Oddity and others David Bowie records to name a few!
Some five or six years ago Geoff Frost produced a rackmounted A-range channelstrip but it didn't last long and i wasn't able to buy one...
Yes I think those records sound fantastic too, and I'd include the early Elton John stuff cut at Trident in that mix, even if you don't like Elton.
The Sound Techniques A Range was pretty much unknown about for years I think.
I got a good peek inside some modules about 12 years ago that were in one of the desks sent to the U.S., possibly the Elektra board but not sure exactly if these were those or not.
I did have the full schematics, one a big photocopy of the original blueprint showing the EQ, and then other bits which I had to trace out including the amp I've posted. Sadly I lost all my documents and library 10years ago except anything I had emailed to anyone or anywhere so...
But the EQ is basically a Pultec passive type except with an inductor peaking low end boost like on the Helios. Only 2 frequencies on the low end if I recall, both with the same L but a switched C. I'm thinking it was 80Hz and 120Hz but it could've been a bit higher?
The amp was the same as I posted for pretty much everything, the Mic input transformer had multiple primary taps for impedance switching and secondary pads @, I think, -5 and -10dB.
I could ask a friend in L.A. who does own two Elektra modules for particulars on freqs etc.
With the blessing of Geoff Frost, Sound Techniques has been picked up again and there is at least one fully built new desk that incorporates the passive A Range eq with the active mid of the System 12. They did have plans to release modules but I don't know if that's still so or if they're just interested in complete desks.
Anyway, have a peek around online for that new product info, I think it's the same website address as Geoff had.
Cheers dude.