Apogee DA-1000
A two-box converter pair that promised jitter under 30 picoseconds - and mostly delivered.
Overview
The DA-1000 is half of a matched pair. Apogee sold it alongside the AD-500, and the two were designed to run back to back: analog in on the AD-500, digital through the DA-1000, analog out again. Apogee's own advertising in Studio Sound (July 1991, p.72) put the DA-1000 at £1,595 and the AD-500 at £1,195. It pitched the pair as a way to "extract optimum performance from your existing digital hardware without substantial reinvestment." The argument was simple. If you already had digital gear, the converters were the weak link, and Apogee wanted to sell you a better one.
The DA-1000 is a digital-to-analog converter. The manufacturer's specification lists 20 bits convertor quantization with 8× oversampling, but only 16 bits on the input side, and the period press noticed the mismatch. It accepts a 32 kHz to 54 kHz input sampling rate range across all its digital inputs. Apogee's headline claim was jitter. The converters were said to reduce it to less than 30 picoseconds, and Studio Sound (December 1992, p.56) noted they didn't have the equipment to verify that number. The internal crystal has a specified accuracy of ±10 PPM, good for frame accuracy over a two-hour period. Apogee also published THD at a typical 94 dB at 1 kHz with the signal 0.1 dB below full scale, S/N at 106 dB flat and 108.5 dB A-weighted, crosstalk at 110 dB from 20 Hz to 20 kHz, and de-emphasis at 50/15 µS. The unit runs on 12 Vdc at 1200 mA, from an 11.5 to 15 V input range.
According to the most detailed period test available, the DA-1000 does two things well: linearity and crosstalk. Studio Sound (December 1992, p.56) ran the AD-500 and DA-1000 back to back and found analog-in to analog-out linearity "the best we have seen to date," with response within 0.03 dB from 20 Hz to 10 kHz and only 0.22 dB down at 20 kHz. The magazine also singled out the DA-1000's crosstalk as "outstanding" and better than the published specification. Group delay through the pair was effectively constant with frequency - the linear-phase behavior Apogee advertised - and Studio Sound called it "the best result we have seen."
There are caveats, and anyone buying one today should know them. The same Studio Sound test (December 1992, p.56) found that the DA-1000's own linearity was excellent on the left channel but showed deviation and accompanying noise at the bottom end of the right channel. The reviewer concluded the unit's true overall resolution was 16 bits, not the 20 bits implied by the converter spec, and that feeding it a 20-bit dithered signal produced "an unacceptable result." That is a channel-matching issue, not a design flaw in the abstract, but a used unit should be checked for it. The magazine also flagged a labeling or software glitch. Setting emphasis ON on the AD-500 did not consistently engage de-emphasis on the DA-1000, even though the test gear confirmed the correct codes were passing. The front-panel switching drew criticism too. Several positions were unlabeled, which the reviewer suspected came from software upgrades adding functions to switch positions originally meant for something else.
The DA-1000 is more flexible than its plain face suggests. Output level at digital full scale is set by a through-the-panel preset per channel, with internal jumpers selecting the basic operating mode. The internal clock slaves to external sources with a flywheel effect that reduces jitter while holding sync, and the unit will lock from below 32 kHz to 54 kHz. Apogee built in divide-by-1.001 and multiply-by-1.001 selections so the user can correct timing when the wrong clock was recorded on the source. That is useful for pulling 44.1 kHz material into line with 44.056 kHz NTSC video. There is also an EIAJ delay function, a half-word digital delay that restores absolute alignment between outputs when the converter is used with F1 recording systems. The metering is minimal on purpose: two LEDs per channel, an amber one that lights within 12 dB of clipping and a red one at 2 dB of headroom, operating in the analog domain rather than on the resulting digital level. Apogee assumed the source device would do the real metering.
By the mid-1990s the DA-1000 had become a reference tool in professional rooms. A plain 16-bit-input DAC held its own against later decoding hardware on tonality. Mix (October 1992, p.83) ran a Bernie Grundman Mastering endorsement in which the engineers reported the Apogee retained more ambience and definition and that the difference was audible all the way to the finished CD. That is marketing copy, but it names the room and the engineers, which is more than most.
The DA-1000 is a 12 V wall-powered box meant to sit next to its AD-500 sibling, and the pair is more useful together than either unit alone. The linear-phase filter behavior is genuine and measurable. The 16-bit input resolution is a hard ceiling for modern work, and the right-channel linearity issue found in period testing is worth verifying on any specific unit before purchase. Production years are not confirmed in the available documentation. The 1991 advertising and the December 1992 review bracket the period in which it was being sold, but the archive has no confirmed start or end date.
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