Pickups

There are still quite a few pickups on the market which are either designed, or can be adapted, for the playback of shellac discs.

The Shure M44-7 cartridge is one possibilty, and is still available at around £50 from Technical & General, P.O.Box 53, Crowborough, East Sussex TN6 2BY, UK and many other outlets such as Musonic. Both suppliers are also a useful source of spares for Goldring Lenco turntables.

A typical 78-capable pickup will have features and specifications similar to those in this list.

• Tone Arm Mount Standard 1/2 inch
• Output Voltage Typical at 1 kHz 9.3 mV RMS at 5 cm/sec peak velocity
• Recommended Load 47 kohm in parallel with 400 - 500 pf
• Tracking Force Effective at stylus tip Range: 1½ - 3 grams
• Frequency Response Essentially flat from 20 to 20,000 Hz
• Stereo Channel Balance Within 2 dB
• Channel Separation Typical at 1 kHz: more than 25 dB
• Accessory Needle For wide groove/78 RPM recordings N44-3

The stylus tip radius is given in thousandths of an inch, called "mil"; its value for these styli is 2.5 mil, which was the industry standard for 78s manufactured from 1954 onwards. The linear output of magnetic pickups requires a pre-amplifier with the ability to correct for the different recording characteristics of 78s of various manufacturers and dates. The preamplifier also boosts the signal voltage by the factor of about 50 needed for compatibility with the PC's sound card line input. A pre-amp circuit can be found elsewhere on this web site.