What is literally a new "twist" in a familiar product is the ADC (Audi Dynamics Corp.) phono cartridge known as the Integra. This pickup now comes integrated (hence the name) with a shell that fits the standard bayonet-mount used on many turntables so that the chore of fitting and wiring the cartridge into a shell is eliminated.

Moreover, the shell is sectioned, and a "twist" of two small knobs permits the user to adjust the stylus for the vertical tracking angle at which most records are now cut. When the lower surface of the pickup is parallel to the top of the turntable platter, the vertical angle is correct, regardless of the "attitude" or height of the tone arm itself.

In addition, the shell is made of carbon fiber, a material that has been credited with reducing the effective mass of the pickup and shell combination. It also provides excellent shielding to eliminate hum, a path to ground for the discharge of static electricity, and a rigid anti-resonant system that reduces any possible distortion that might be caused by "loose" resonant setups.

Installed in a Yamaha YP-D71 turntable, and adjusted for 1.25 grams of bertical tracking force, the ADC Integra proved to be an excellent phono pickup. Tracking, including the recent Telarc digitally processed Tchaikovsky Fourth which can offer formidable groove problems to lesser pickups, was excellent. The sound generally was full and clean across the audible range. Top model in the Integra series is the XLM-III ($130); slight variations in stylus tip and in tracking force are found in the other two models (the XLM ii, $110; and the XLM-i $70).

Q. I have more than 25 reel-to-reel tapes recorded in Switzerland on a Grundig recorder. I would now like to transfer them to cassettes. Can you advise me as to what size cassette to use, and so on?

A. For serious cassette recording, especially of music you wish to preserve, do not use any size cassette larger then the C-90. The C-120 size cassette uses thinner tape with inferior response, and it also may put too much of a "load" on the casette deck's mechanism. The C-90 size provides nearly 45 minutes of stereo per side; the C-60, nearly 30 minutes per side. Relating these timings to the running times of the material on the open-reel tapes can help you fit the music comfortably onto the cassette tapes. oYou also should check the signal levels of the European-made reel-to-reel tapes. If they were recorded through the typical European "DIN" circuit, their volume may be lower than is customary for direct interfacing with "line" inputs on U.S. recorders. If you are not technically sophisticated in this particular area, shop around for an audio dealer who can help you.