Agnew Analog News

J. I. Agnew (69)

Presto 1-D Cutter Head Feedback Modification

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.


Rebuilding an Audax R-56 Cutter Head with Feedback

This Audax cutter head arrived with a fried coil and a completely crusted armature. The damping material had not aged well.

A complete disassembly, cleanup and reassembly would be required, with the renewal of the damping material and drive coil. This was yet another perfect candidate for our feedback modification.

Fitting a Neumann Cutter Head to a Presto Lathe

Neumann cutter heads have a rib along the back, for mounting. Presto lathes, on the other hand, together with the vast majority of non-Neumann vintage lathes (Rek-O-Kut, Fairchild, etc.), have a mount with two slots, for cutter heads with two threaded holes on the back (Audax, Presto, Fairchild, RCA, etc).

A Fashionable Rek-O-Kut Lathe Cabinet

Have you ever noticed the total absence of audio equipment from the luxury houses presented in glossy architecture and interior design magazines? It makes the inhabitants of such property come across as rather uncultured.

In fact, not only is an audiophile grade sound system a minimum requirement for the home of anyone affluent enough to hire an interior designer, but it is important to choose a designer who can appreciate the aura of sophistication and intellect projected by a beautifully restored vintage disk recording lathe, set in a handcrafted custom cabinet, in a conspicuous corner of the living room!