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Our upgrade paths for the DAC-1 build on the already excellent performance and focuses on reducing system clock jitter, lowering power supply noise, and improving signal integrity. Our starting point with the upgrades is the power supply, the Benchmark has now means to filter the AC input; so here we add a pair of Bybee Large Quantum Purifiers which considerably reduce noise on the incoming AC power. The sonic gains here are not subtle, music has reduced grain, is more open  natural sounding. The Bybee are effective even if there is AC Mains conditioning already in the system, the Bybee reduce 1/f noise so this combined with external mains filtering will have a collective affect. We then move to the DC regulated supplies, the DAC1 is moderately regulated with a +5V & 3.3V regulators for the digital circuits, and +/- 18V regulators for the analogue output stage. The regulators are heat sinked to the case, and with no space facility to mount lower noise, discrete types, to drive noise levels down, we add Bybee Slipstream purifiers to the regulator output. This gives an immediate improvement to the sound which improves over a burn-in time of approx. 200 hours. The sound is more open and spacious, backgrounds are quieter, lower frequencies has more energy and impact.

The AD1853 DAC used in the DAC1 has an external master clock input, in this case in the form of a TCXO oscillator. Benchmark use a ‘sample rate converter’ to isolate incoming jitter from the DAC. Given the claim that incoming jitter is completely isolated the jitter of the TCXO clock determines performance. While the TCXO does provide improved temperate stability (ppm) it cannot provide very low phase noise due to the limitations of the internal ‘Pierce’ oscillator of the TCXO, and its shared power supply. Since the quality of clock here contributes to the DAC’s performance; lowering jitter enables the DAC to perform closer to its maximum performance, so we enrol the Superclock 4 to achieve this. Replacing the TCXO with Superclock 4 has a twofold affect, the DAC is referenced to a ultra-low phase noise clock, and the very low noise regulated supplies of Superclock 4 mean the DAC’s internal 3.3V supply can be left to take care, uninhibited to the rest of the digital circuits. Adding Superclock 4 brings a marked improvement in sound quality, music gains extra body and depth, openness, improved stereo focus and more lifelike tonal balance.

Earlier generations of the DAC1 used the NE5532 extensively in the analogue stage for Current-to-conversion, low-pass filter and buffer; 3 pairs in total. These are 3 hyper critical stages that directly follow the DAC and the selected op-amp puts its stamp on the sound, for better or worse. Later DAC1 models were factory fitted with the high quality LM4562, a positive step for the manufacturer and certainly for sound quality. We offer this upgrade in the form of the newer LME49720 op-amp, of the same family as the 4562, but we slightly prefer the sound of the LME49720. The 49720 amp has ultra-low distortion; 0.00003% THD, ultra-low noise; 2.7nV/ √ ^Hz, and a high power supply rejection ration; 120db (the op-amps ability to reject noise); qualities that are clearly translated to improvements in sound quality compared to the aged NE5532.

Benchmark DAC1 Level-1 upgrade

2x Bybee Large Quantum Purifiers for AC input.
2x Bybee Slipstream Purifiers for analogue +/- 18V DC supply

Superclock 4 master clock for AD1853 DAC.

WBT4% Silver solder throughout.

Benchmark DAC1 Level-2 upgrade

2x Bybee Large Quantum Purifiers for AC input.
2x Bybee Slipstream Purifiers for analogue +/- 18V DC supply
1x Bybee Slipstream for +5V DC supply.
1x Bybee Slipstream for +3.3V DC supply.

Superclock 4 master clock for AD1853 DAC.

WBT 4% Silver solder throughout.

Optional Extras

6x LME49720 op-amps for analogue stage.

*Please contact us for custom upgrades.