Sony PCM-F1
A consumer PCM processor that studios quietly adopted as their own, and then argued about for a decade.
Overview
The pitch that sold the PCM-F1 was price. The retail price of "consumer-type" PCM units had fallen well below $2,000, which put a 16-bit digital recording system within reach of anyone who could afford a decent open-reel deck. The PCM-F1 itself was around $1,850 without a transport. You supplied your own videocassette machine, Beta or VHS. That was either the smartest thing about the design or the most annoying, depending on whether you were a home recordist or a broadcaster trying to package a field rig.
The PCM-F1 is a processor, not a recorder. It encodes audio as digital data onto videotape, and the cost of the recording medium becomes competitive with analog. A T-120 VHS cassette ran about $15 and held 120 minutes, against roughly $20 for a 10½-inch metal reel carrying 90 minutes at 1-mil tape. Videocassettes are smaller and lighter than open-reel counterparts, so distribution and storage costs drop too. Audio (March 1982, p.49) noted the PCM-F1 was one-eighth the volume, one-fifth the weight, and one-third the price of Sony's previous digital audio processor.
Sony offered 16- or 14-bit quantization. The 16-bit mode bought another 4 or 5 dB of signal-to-noise and 0.005% THD, against 0.007% at 14-bit. The F1's analog I/O was consumer-grade in the literal sense - about 0.5 V on phono plugs. That is why so many studio users ended up buying level-matching boxes to get it up to line level.
Then there's the flaw that every F1 owner eventually learns about. The digital-to-analog converter was borrowed from the CDP-101 compact disc player - a single 16-bit linear device processing left and right channels alternately. That produces an 11 µs delay on the right channel relative to the left. Played back through the F1 alone, it's inaudible. Parallel the channels for mono, though, and you get a 3 dB drop at 20 kHz. Worse, the F1's digital output isn't time-coincident. Transfer an F1 signal digitally to a 1610 and the two discrete D/A converters there mean the material is no longer truly mono compatible. Audio+Design built a box with a switchable 11 µs delay in the right-hand input channel to put things back in step. They also compensated the left-hand replay circuit and supplied stickers to mark tapes that had been treated. Then the first batch of modified PCM-701 units had the delay in the wrong leg, recording signals 22 µs out of step instead of fixing them. A+D fixed it quickly and even produced a gadget to restore the 22 µs, but for some it was too late, and their recordings had been mastered with a 6 dB loss of HF in mono. The trade's fix was to record a 10/12 kHz tone at the head of F1 tapes in addition to the usual 1 kHz. A 1 kHz tone will show phase error on a scope, but an HF tone makes it obvious on a phase meter and audible when you switch to mono.
None of that stopped the F1 from becoming a fixture. Modern Recording (March 1984, p.51) described a "not-so-secret cult" of F1 users. It noted the unit had been intended for affluent consumers who wanted state-of-the-art home digital but weren't prepared to pay the roughly $25,000 for a professional-type PCM processor, and that professional popularity continued anyway. Audio (April 1983, p.63) observed that barely a year after examining the PCM-F1, the processor had found its way into applications its creators probably never dreamed of, including yeoman's duty at Chicago classical station WFMT as part of a remote master recording system for live performances. One 1982 piece in Recording Engineer listed the F1 at around $1,850 without transport alongside the Technics SV-P100 at about $2,500 (reported as low as $1,900 in some locations) and the Hitachi PCM V300E at around $3,500.
The studio workflow was straightforward: record in the field with the F1, then transfer those digitally recorded tracks to a multitrack. Broadway Video used an F1 16-bit unit for a final mix to digital two-track, output recorded on ¾-inch U-Matic videocassette striped with timecode. The digital tape kept generation noise down, and with timecode on it the master could be carried right up to the feed of a cable network or head end, provided the uplink had another F1. Visual Eyes ran an F1 encoding digital signals onto the facility's BVU-800 U-matic, and MIDI scores from composers were routinely recorded straight from the synthesizers onto videotape via an F1 at the scoring studio.
R-DAT eventually replaced the F1. The trade framed it as more than a convenient replacement for the PCM-F1 and PCM-701ES. DAT offered fast rewind and access, low error rates, rare dropouts, and space-saving hardware with simple controls. One catch mattered for anyone mastering CDs: domestic DAT machines, without serious modification, wouldn't record at the compact disc sampling frequency of 44.1 kHz, running at 48 kHz instead. With the F1 it had been possible to make direct transfers to the 1610/1630 system using one of the readily available digital interfaces. That path closed with domestic R-DAT. The professional audio community had noticed the quality and cost-effectiveness of these consumer formats and adopted them anyway, the F1 among the first.
For a buyer today, the F1 is a system purchase, not a single box. It needs a working Betamax or VHS transport, and the analog I/O being 0.5 V on phono plugs means level matching is part of the setup. The 11 µs channel delay is inherent to the design and worth knowing about before any mono sum. The tapes are the medium the whole thing depends on - 120 minutes on a T-120, roughly $15 at the time.
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