"Nyquist is built around the ESS ES9018S Sabre DAC, one for each channel. Each 9018 DAC incorporates eight separate digital-to-analog converters; their outputs are combined to lower the noise floor, randomize any conversion errors, and create a balanced output signal. Brinkmann uses only the DAC portion of the Sabre chip, ignoring its integral PLL and upsampling digital filters. Rather than use these compromised sub-systems, the Nyquist has a separate Brinkmann-designed PLL and re-clocking circuit to reduce jitter. The clock is said to have very low phase noise, and is located right next to the DAC chip (the point where jitter matters). Similarly, the digital filter is implemented in a separate DSP chip running Brinkmann’s custom filter software. This filter upsamples all incoming PCM data to 352kHz or 384kHz for conversion to analog. Sources at 44.1kHz or multiples of that rate (88.2kHz, 176.4kHz) are upsampled to 352kHz; sources at 48kHz or multiples of that rate (96kHz or 192kHz) are upsampled to 384kHz. This dual-frequency scheme avoids sonically degrading non-integer upsampling. Interestingly, the 3.3V that supplies the ES9018S DAC chip is derived from the 160V rail that supplies the tubes. Brinkmann found that this supply technique improved the sound compared with powering the DAC chip from a conventional supply" .
@langla4,
I posted This to point out that this DAC has an output voltage of 3.3V.
The two preamplifiers you’re interested are both considered to be sonically excellent. The one potential drawback is that both are high gain (Particularly the CJ ET7 with 25 db of gain). The Cary has about 18 db of gain.
This level of gain coupled with your DAC’s relatively high 3.3V output could result in excess system gain. This would limit your volume control range of use. You may not be able to use the volume control above say 9 o’clock (Or thereabouts) as it will be too loud. Just a point to consider.
With the DAC's 3.3V output, 10 db of preamplifier gain would be plenty. You also need to factor in the sensitivity of your speakers. The higher the sensitivity, the less system gain required. One more factor to be aware is the input sensitivity of the Decware tube amplifier. The more sensitive it is, the less system gain is required.
Charles
