The Westrex 2B is a motional feedback cutter head, introduced in 1952 by the Western Electric Export Company. It followed hot on the heels of the Westrex 2A, dating from 1947, which was itself a lateral implementation of the principles first described by Wiebusch, Vieth and Yenzer in 1938, with a couple of relevant patents issued by 1939, for a vertical cutter head employing motional feedback.
The Fairchild line of disk recording lathes, first appearing in the early 1930’s, featured a General Electric hysteresis synchronous AC motor, running at high speed, with a worm and gear reduction to drive the platter. While this system in its various permutations in their different models was impressively well made and performed well for its time (see here for a more detailed description and pictures), a direct-drive system with a floor mounted motor is clearly the way to go if the highest level of performance is to be attained.
Our popular Agnew Analog Reference Instrument Type 1501 Stylus shank adapter was intended to make it possible to use the Neumann-style taper shank stylus (Transco 320, Adamant NSH-2, etc) with vintage mono heads such as the Presto 1-C and 1-D, which need a long shank stylus.
Up to now, customers would just install the adapter and leave it there, only occasionally replacing the stylus. One customer, however, wanted to be able to leave the stylii aligned in the adapter, and change them out without needing to realign.
In the darkest corner of the catacombs under the lab, illuminated only by glowing directly-heated triode filaments, top secret experimental research is being conducted…
Presto 1-D and 1-C cutter heads are frequently encountered on our lab bench for repair and restoration. Some are just regular repairs to original spec, others are rewound to a different impedance, but some undergo more comprehensive and exciting modifications!
We have previously examined modifications where a feedback system was added to a Neumann MS-52H and an Audax R-56 cutter head. This time, we shall discuss adding feedback to a Presto 1-D, which arrived with damaged coils.
