Grampian Ambiophonic Unit - Type 666

Grampian Ambiophonic Unit - Type 666

In addition to all our Grampian 636 information, we also picked some info about the Grampian ‘Ambiophonic’ Unit, Type 666. An interesting (and very rare) piece of 60s gear: a version of the famous Type 636 designed to use the reverb “to alter apparent room acoustics” in auditoria.

We’ve been fortunate enough to have one of these (pictured above and below) come through our hands; essentially what you have is a broadcast-quality, very clean-sounding Grampian Type 636. So it won’t produce the famous overdriven distortion, but produces a great, rich reverb effect that is good with pretty much anything. Very uncommon, these were apparently built for the BBC and used by BBC Radiophonic Workshop.

Below are links to the documentation we were given – you can view and download from the links below. Note that these were given to us to distribute and are free to use, however if you use, re-post or share them then please add a credit and a back link.


 Original Grampian Ambiophonic brochure & technical spec


 Schematic: Grampian Ambiophonic Unit Type 666


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