The comments below may not reflect the as-new performance of the Fairchild cartridges, due to deterioration of the compliant stylus/coil-suspension parts. However, based on the performance detailed below on a 225-A, I suspect that most of the original performance has survived.
I was around circa 1962 when stereo cartridges tracking at 2 grams and under became widely available and essentially banished record wear. Thus, I have been reluctant to play any pristine original-purchase records in my collection with heavy-tracking vintage cartridges. But I have a few mono LP's that have been subject to high tracking forces before, plus those purchased more recently on eBay and in flea markets. These I have thrown to the Fairchild's.
Models below the 225-A track at 6 grams or more and I have listened to my samples only for short times. (Note that the "B" and "C" models equipped with 78-rpm tips require far higher tracking forces and are thus not good candidates for 1-mil retipping for LP playback.) The 225-A, however, tracks many LP's at 4-5 grams which seems more reasonable to me. (My CBS STR-120 test record warns against the partial wipe out of signals beyond 15 kHz for tracking forces above 2 grams, presumably for the 0.7-mil tip diameter. The 1-mil tip of the 225-A would permit a somewhat higher force.)
I have made a few frequency-response measurements using the RIAA-equalized lateral (mono) tracks on CBS Laboratories professional cartridge-evaluation LP's of the 1960's. I do not have a chart recorder for the convenient sweep-frequency tracks, so used the tracks which have 29 voice-announced discrete frequencies, 20-20,000 Hz (sort of a pain). The test cartridges fed an Apt Holman Preamplifier phono input with infrasonic filter defeated (standard RIAA equalization; 47,000-ohm/100-picofarad load). The signal was read at a tape output with a Fluke 29 multimeter in sine-wave mode.
The following chart shows a Fairchild 225-A (with unworn stylus and tubular stylus shank) tracking at 4-5 grams:
- In a circa-1960 Shure M236 arm (red curve). The elevated very-low-frequency (VLF) response may be due to insufficient arm mass for the compliance of the 225-A. (Even though the M236 would I believe be classed as a high-mass design by today's standards.)
- In the stock low-mass arm of a TD 126 MK II turntable circa 1973 (purple curve). The curve is shown only at 300 Hz and below since this is where the differences were. (See a picture of the setup at the top of my homepage.) Note the highly elevated and erratic VLF response, due I would guess to the mass of the Thorens arm being way too low for the Fairchild.
Note: for reference, I played the same STR-130 cut with my circa-2001 Shure V15Vx tracking at 1 gram in the Thorens setup. The V15Vx is the top-line Shure and has become my day-to-day reference. I expected to see an extended VHF response compared to the Fairchild, but the response above 12 kHz or so was not much different from the Fairchild 225-A (low-frequency response was much smoother). It occurs to me that I very likely damaged my STR-130 test record by playing the 225-A on it first. Also, while very clean, the STR-130 was a pre-opened eBay purchase and with a light spindle mark or two.
More on the above subjects subject later.
