Disc Players

This latest top-loader [see boxout, p59] employs the same digital building blocks - Burr-Brown's DF1704 96kHz digital filter and partnering PCM1704 DAC (one per channel) - that we've seen in earlier Exposure players, including the 3010S and 3010S2. The DF1704 is some 23 years young but still offers a solid 119dB stopband rejection from what, these days, would be called a 'fast' linear phase filter. There's no observable ripple at the top-end of the filter/DAC response either, the 3150 CD reaching out across 20Hz-20kHz within ±0.03dB. Track access is fast and error-correction excellent, then again Exposure still has supplies of the Sony KSS-213C transport (a true CD pick-up, not a DVD transport) with a Toshiba decoder.

So, while the blocks are the same as we've seen before, the 3510 CD has a 'tweaked' discrete output stage and improved PSU that contributes to the slightly reduced 0.00045-0.011% distortion (20Hz-20kHz) vs. 0.00075-0.017% from the 3010S. The slightly irregular trend of distortion versus level [see Graph 1, below] is a feature of the DAC, not the analogue stage. Meanwhile, peak output is unchanged at an industry standard 2.0V and while the 102.5dB A-wtd S/N ratio is slightly poorer than achieved by the 3010S, the newcomer's low-level linearity is very slightly better at ±0.3dB over a 100dB dynamic range just as digital jitter is slightly reduced from 134psec to 120psec here [see Graph 2, below]. Do bear in mind that the minimum jitter that's measurable with 16-bit data lies at around 116psec, so 120psec is very near the limit. Finally, output impedance is a low 45ohm through the midrange but increases below 100Hz to 245ohm/20Hz. Stereo separation is a fine 115dB/1kHz and channel balance is within 0.1dB across 20Hz-20kHz. PM

Above: Distortion versus 16-Bit digital signal level over a 120DB range (1Khz, Black; 20Khz, Blue)

Above: High resolution jitter spectrum with 16-Bit CD data. residual J pattern accounts for ~116Psec