GE's patent, filed May 2, 1960, acknowledges Peter Ernest Pritchard as the inventor (see above). Since most tonearms of the time had too high a mass for the ADC-1, Pritchard designed and produced the ADC-40 arm to accommodate his cartridges, which allowed them to perform well at tracking forces of 1 gram or less. The ADC-40 had a tapered wooden shaft and anti-skating compensation, then both notable and unusual. Prior to the emergence of moving-coil pickups with their more limited compliance, the ADCs (along with Shure's V-15 line) were pace-setters in phono cartridges.
Pritchard's ADC also introduced a line of interesting loudspeakers based on then-exotic KEF drivers (including the legendary B-1814 rectangular flat-panel woofer) and. later, a very successful speaker line produced locally in New Milford. Pritchard sold ADC in the late 1970s and began producing the successful Sonus line of phono pickups based, again, on the principles on high compliance and induced magnetic design and exemplified by the popular Sonus Blue.
I was an ADC and Sonus fan for many years and thought I had achieved audio Nirvana when I set up the XLM in the ADC-40 on my Empire 208. I also coveted his KEF-based speakers and exchanged a bit of correspondence with Pritchard in the 1960s. I remember his responses as gracious and extremely practical. I am writing this from my house in New Milford and there are reminders of him and ADC to this day, as we often drive down Pickett District Road where ADC was based. We frequently come upon ADC products at the local flea markets and, just recently, I was able to purchase a number of NOS styli for my ADC-25 cartridge. Maybe it is time to re-install it in my SME-III arm for old times sake. Thanks, Peter.