We tested two samples of the ADC-1 phono cartridge, both of which were taken from a dealer’s stock. One was a demonstrator that had been in use for some months. The other was brand new, right off the shelf. Both were tested in an Empire 98 tonearm and in a Gray 108-C tonearm with its damping lightly adjusted, but results with both cartridges were for all intents and purposes identical in both arms.
The ADC-1 requires the standard 47k-ohm input termination, and its output voltage is about ideal for all current preamp designs. We adjusted the ADC-1’s tracking force for the cleanest possible tracing of the most heavily cut musical recordings in our collection (some Command discs and some recent Londons), and arrived at an optimum force of 1.25 grams in the Gray arm and 1.5 in the Empire arm. Unlike many wideband cartridges, the ADC- l’s treble response was not audibly influenced by tracking force.
Measurements
Preliminary checks showed the ADC-1’s frequency response to be well within ±1dB from 20Hz to about 8kHz. Above that, one of our test samples rose to 3 and 5dB up at 10kHz while the other hit +2.5dB at the same frequency. Above 12kHz, both started to roll off rapidly, being respectively –3dB and –4dB at 15kHz. Separation measured >25dB, all the way up to 9kHz, and was still reading 12dB at 15kHz.
Hum sensitivity was rather high for a cartridge of this general quality, so it should not be used with a turntable that has a reputation for causing hum problems. (Most transcription tables and top-notch changers would be satisfactory.)
Sonically, the ADC-1’s middle and low-end sound was identical to that of our current testing standard—the Weathers PS-11, and its overall sound was remarkably clear and transparent. At the high end, however, the response hump caused a subtly snarling and distinctly spitty quality in the sound.
At 1.5 grams force, its ability to trace very high groove velocities, even in inner grooves, was surpassed only by the Weathers pickup, and was comparable to that of the Empire 880P (which we tested in Vol.1 No.3). But when it did break up, it did so less pleasantly than did the 880P, which in turn was adjudged inferior to the Weathers in this respect. The 880P sounded harsh when breaking up; the ADC-1 had a grating, “skritching” kind of breakup, even through a system with very low distortion and a smooth speaker. Some preamp distortion and a few upper-range peaks in the speaker would make the ADC-1’s breakup sound pretty painful.
Actually, the ADC-1 had hardly any more response rise at the upper end than has the Weathers PS-11, but in the Weathers, the rise starts at a higher frequency and continues to rise above that, instead of falling off again to produce the equivalent of a mild peak. Evidently, this plus the superior high-level tracing ability of the Weathers (probably due to lower-moving mass) accounts for the latter’s superiority.
As far as compliance is concerned, the ADC-1 appeared to have a clear-cut edge over the Weathers. Although the PS-11 does have very high compliance, it has it over a relatively small amplitude of stylus movement, while the ADC-1’s stylus is free to flex over an almost alarming distance. As a result, the ADC-1 was clearly superior in tracing extremely wide groove excursions, as are found on the loudness-compensated side of the Cook Chromatic Scale test record. On the other hand, we have never encountered any recording of natural sounds—musical or otherwise—that has half the low-frequency level of the Cook disc, so for all practical purposes, the extreme flexibility of the ADC-1’s stylus seems of questionable advantage.
It may even be somewhat of a disadvantage, for although we were unable to hear any separation problems, the measured separation tended to diminish momentarily with each revolution of the slightly eccentric test disc, as the stylus was flexed out of its normal symmetrical position with respect to the pole-pieces.
For this reason, we would advise using the ADC-1 with a relatively lightweight tonearm, whose inertia is low enough to follow the normal motions of warped or eccentric discs. ADC’s own “Pritchard” arm would be a good choice, as would, for instance, the Weathers “Universal,” the Shure M-232, or the Ortofon RMG-212.
Conclusion
Our standard pickup has yet to be equaled, but the ADC-1 and the 880P are close contenders for second place in the current field. Of these, we would choose the Empire 880P, simply because our electrostatic tweeters are unmercifully accurate reproducers of high-end distortion. The ADC-1 does however have a slightly fuller low end than the 880P, so your choice here will depend upon which aspect of performance you are more critical of.