Sony PCM-1

The first consumer PCM processor, predecessor of D.A.T. and the first commercially available A/D & D/A converter, except it didn't have a digital output other than the video signal sent to the VCR.
At 15,000DM, in 1979 (with a SLO-320 Beta recorder included) or 4400$ in 1980, however, this wasn't exactly "consumer" style !

The analogue-to-digital chip was sourced from Burr Brown and the digital-to-analogue chips from Texas Instruments - Sony would only launch its own CDA and CDX production program in 1979, when the CD standard would be well under way.
By which time Sony already had functional prototypes of integrated recorders, either Beta-based, cassette-based and even mini-cassette-based.


Back to 1976 -
Although Sony already disagreed about this low resolution, the PCM-1 was a 14-bit deck and thus conformed to the then recent EIAJ standard - compromises often lead to established standards.
Sony would however impose 16-bit depth when the CD standard was discussed, straying Philips and many others from their renewed 14-bit recommendations - patience is a virtue.

Quantization is in fact done at 13-bit per channel, with a C-MOS sample/hold (analogue) circuit passing the left and right information altrenatively to the single a/d converter ; a 4:1 and 1:4 compressor before and after the switch allows dynamic range to reach that of a native 14-bit system.
16-bit chips handle error correction ; being an NTSC unit, sampling was fixed at 44,056Khz.

The needed bandwidth for the total 1,400,000 bits per second is of 1,7MHz ; the global quartz clocking cycles at 14,068MHz. A switchable 50µs emphasis allows to gain 7db in s/n ratio.

Audio inputs and outputs rely on balanced XLRs and unbalanced RCA while the single video i/o loop starts and ends with unbalanced 75 Ohm RCAs.

The november 1978 US sell-sheet advertises the PCM-1 as compatible with either the Betamax or U-Matic fomats : Betamax was Sony's own but U-Matic had been co-developped by Sony and Matsushita and therefore... JVC.
Since Sony had no stake in VHS, it was previsible this format wasn't "recommended" by Sony - but it would become so several years later.

Build-quality is unbelievable and as massive as an ST-A7B for instance : multiples layers of aluminium and welded steel back-plates make the sculptured front while, inside, only large plug-in type cards are used for a 19kg total of 1977 cutting edge technology.


Graphs and oscilloscope measurements comparing signals recorded by a 38cm/s reel recorder and that of a PCM-1 + VTR used at length by Sony and throughout the press showed the immense and clean superiority of the latter.
It took however quite a long time for recording engineers (and audiophiles) to accept digital not as technically better (that was obvious, even then) but as better sounding.

And some ears still aren't convinced of that, thirty years later : the gradual and soft distortion of analogue tape recorders still remains far more human than the simply radical on / off clipping possibilities of digital...


Spearheaded by Sony, D.A.T. finally replaced all VTR/PCM combos, whether Sony's own (PCM-10, PCM-F1, PCM-1600, PCM-501ES, PCM-601, PCM-701ES) or that of others : Sansui's PC-X1 Tricode, Nakamichi's DMP-100 (a rebadged PCM-F1), Hitachi's PCM-V300, Technics' SV-P100 or Toshiba's XD-80 and XD-60 - and most of the latter still were strict 14-bit circuits, too.

None of these managed to sell as well as Sony's own units because Sony -and nobody else- made digital recording a viable industry standard.
It is with Sony's experience in PCM that Philips did finish and market the CompactDisc format. And in 16-bit, too, thanks to Sony.



Besides the extremely complete AUDIO (USA) 1980 review posted here, an interesting 1979 text can be read at Stereophile.com, with a PCM-1 in it.