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To actually use the Taurus as a balanced headphone amp obviously relies on a—likely aftermarket—balanced wiring harness for your cans of choice. Such a harness allocates dedicated grounds to each channel. Your standard 3.5/6.3mm plug shares that ground with both channels. It thus also shares possible noise riding on it. Here a balanced headphone cable must be terminated like an old AKG K1000. That makes it a single 4-pin XLR* rather than dual 3-pin equivalents. The RCA/XLR pre-outs on the back of the Taurus meanwhile transform this petite component into a minimalist transistor preamplifier without remote control. For now that only leaves a matching speaker amplifier on the company's books to have a complete 3/4-width system package.
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* Pin wiring is 1 left positive, 2 left ground/negative, 3 right positive, 4 right ground/negative.

As my auditions with their ARK MX+ had shown, the two AURALiC principals may be newer to our industry but possess good ears and engineering resourcefulness to author very mature products that with the converter impressed with a high price/performance ratio and excellent build quality. Would the Taurus follow suit?


First a few tips from Wang Xuanqian.

  • Burn-in of 100 hours is necessary to perform close to target but it will only be after 500 hours that the sound has fully matured.
  • Warm-up in my experience is about 30-60 minutes.
  • Try to place the Taurus on its own for best sonics. Stacking it with our ARK MX+ or other components is not recommended.
  • Try to only connect one type of output to avoid noise induced by the cable or other equipment. When listening to headphones be sure to disconnect the other outputs on the back.
  • Since the Taurus is a high-input impedance design, it is sensitive to interconnect quality. Use high-quality shielded cables. Non-shielded cables like Nordost are not recommended because they may pick up hum.
  • The Taurus itself is very quiet. If you encounter hum or other noise, it will be a system ground loop. Try to use a different AC mains socket to break the loop.
  • The Taurus is a class-A component. While even after long-term use the chassis only gets a little warm, it is hot inside so pay attention to placement and ventilation.
  • Experiment with either mode for different headphones. The largest power transfer does not automatically imply the best sonics. We for example prefer BAL mode for the HifiMan HE6 even though STD delivers more power into their impedance. While the Grado RS1 and PS1000 also operate at 32ohm, with them STD is better as it is with the now discontinued AKG K100. For the Sennheiser HD600 and HD800 meanwhile BAL is much better.
PS: Be sure to also upgrade to the latest firmware (build 6023) for the ARK MX+. It is a huge sonic improvement and provides better OS X compatibility. - 王轩骞

These tips hide a minor functional flaw based on a purist decision. The headphone/pre-outs are paralleled on the same circuit without a selector switch. They're simultaneously live. Presumably to avoid a relay, inserting headphones does not mute the pre-outs. If you thus leave your cans connected while using the Taurus as a preamp, there's a good chance that output voltages appropriate for the big system could permanently cripple your headphones. Practice better safe than sorry. Never use the Taurus as preamp with inserted headphones. The recommendation to disconnect pre-out cabling during headphone use reflects the fact that without it the Taurus 'sees' two loads (i.e. also the input impedance of the power amp). The question is, who really wants to fuss with daily cable swaps? This is how purist design decisions can become a bit hair shirt in practice. Each output is individually buffered however.

"In STD mode all outputs are active*. In BAL mode the RCA outputs and 6.3mm jack are muted. Then just the XLR outputs are active with a maximum output level of 36Vrms. For best sonics we recommended to never connect RCA or XLR outputs at the same time. As soon as you plug the power cord in, the Taurus will be in deep standby mode for power dissipation of just 0.1 watts. Turn the unit on/off with the 'power' switch on the front panel. The volume control changes the level of the analog outputs and headphone jacks in concert over a range of -80dB to +16dB."
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* Thus a 6.35mm mono/TS plug creates a short that would destroy the Orfeo output modules. Never use a mono plug - not that you would have any legitimate reason to do so.


Wang Xuanqian explained their rationale behind certain decisions: "The headphone output and pre-outs are paralleled. The only difference is that the pre-outs have a DC blocking capacitor and the headphone outputs are wired direct. It is true that we decided against individually controlled selector relays. This admittedly functional compromise is based on the unit's size and other factors. During the initial design stage we considered adding a control button to switch between headphones and pre-outs. Then we found that adding another button without destroying the beautiful front face was almost impossible. Plan B was to add a headphone jack insertion detection circuit. This would activate/deactivate the unused outputs automatically. But it proved impossible to design such a circuit without compromising the sonic quality of the headphone outputs. So we preferred to compromise on functionality rather than sonics.


"In BAL mode the four output channels inside the two Orfeo modules create the individual working status. If we were to activate the unbalanced outputs simultaneously, we'd lose two channels on the RCA and 6.35mm outputs. Perhaps it would be acceptable on RCA but for the 6.35mm output it is a disaster. We'd give up half the current output which equals to 3/4th power when driving low-impedance loads like the HE-6. That's why in BAL mode the unbalanced outputs are disabled. Since there's no switch between headphone/pre-outs we could not disable the headphone jack and keep the RCA output live. In 99% of all cases it's actually fine to keep the pre-out cables connected while listening to headphones. The only potentially negative effect is a reduction in THD at maximum voltage swing. During normal listening there is absolutely no measurable or audible difference. And who listens to a headphone at more than 4000mW? The only adverse condition would be a poorly designed power amplifier whose inputs are shorted to ground with a low-value resistor when powered off."
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