via this auction
"Here’s a Simmons SDS7 Drum Brain made in St. Albans/Herts England in the early 80’s. The state of the art in electronic drums is the Simmons SDS7. The two major developments for this kit are its sound generating capabilities and its programmability. In terms of the sound, it is the first drum synthesizer (electronic kit or drum computer) that uses digital chips and analog synthesis to provide ample control over fifteen different sound parameters for the drums and cymbals.
The SDS7 will store ninety-nine sounds per drum arranged as ninety-nine drum kits. Added to that is the programmable selector pad which gives access to any sixteen of the nine sets at the touch of a finger. I still say that it is the only electronic drum brain out there that can come close to the sound of the SDSV or SDS5 drum brain sound. The brain comes with NO pads or stands. This brain module is in excellent shape, all knobs are there and work. It has a buzz in the main output jack, but if you use the separate output for all channels there's no buzz.The brain is almost fully loaded with ten modules. It has one Bass module, Bass 2 module one Snare module and Seven Tom modules. It also comes with a selector pad and one very rare vintage Memory Cassettes. These are extremely rare to my knowledge. I have only seen 3 on eBay in over 10 years. With the selector pad, 11, 12 ,15 and 16 work after it's been on for a some time. I never used it much. I know that it is a brain problem and not the selector pad. Number on the back is 72377.
This brain back in the day, with all it's loaded with, would have cost over $5000.00 dollars."
