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Is a pre-amplifier still relevant to digital audiophiles?

  • The in-between days. During November’s listening periods with the Red Wine Audio Signature 57 I played a frequent switcheroo between it and a pair of Wyred4Sound mAMPs. With the RWA intergrated packing its own volume control I’d run the Resonessence Labs INVICTA Mirus DAC source-direct into the the Californian Class D monoblocks. No need for a pre-amplifier when running this DAC’s digital volume in the upper-quartiled safety zone, where word-length truncation doesn’t eat into the music.

    In the Red Wine coverage I likened Wyred4Sound minis’ sound to that of a high-quality vodka with a hint of peach; the subtle fruit infusion being indicative of EJ Sarmento’s ability to sidestep the reputation established by the earliest ICEPower implementations: needlepointy on detail delivery, cooler on tonal colouring and a starchy on aftertaste. If anything, Sarmento’s mini range, that includes the mINT integrated, display occasional shades of humidity and tenderness. Note: I’m purposefully avoiding ‘tubey’. The mAMPs pull way ahead of the mINT with transparency on upstream changes; they’re a reviewer’s dream ticket.

    However, my first taste of a source-direct setup wasn’t as enjoyable. It arrived courtesy of Bel Canto in 2010 when I ran an eOne DAC 3 D/A converter directlty into a S300 power amplifier. The results were underwhelming: thin, reedy and barely enough juice in reserve for the (admittedly thirsty) ATC SCM 11. After a week of trying to acclimatise to this new sound, I returned the power amp and took an S300iu integrated in its place. Much better! Tonal mass and drive returned to the picture. Remember tonal mass – we’ll be coming back to it.

    Three years down the line and I’m once again immersed in a similar setup. The question simmers: with volume-attenuating DACs so prevalent, do we still need traditional pre-amplifiers?

    The digital audiophile is being encouraged to ditch his traditional pre-amp to save on dollars and interconnecting cables. Source direct is close(r) to the oft-touted nirvana of a ‘straight wire with gain’. Whatever your take on that ideology, the argument for running a DAC direct into power amplification, circumventing the pre-amplifier altogether, makes intuitive sense. Why run with more boxes and/or gain stages than the minimum required? Less IS more. William of Ockham, he of Occam’s Razor, would no doubt approve: “Entities should not be multiplied unnecessarily”.

    Let us pause for thought. The role of the pre-amplifier is three-fold. ‘Passive’ pre-amplifiers handle source selection and volume attenuation. ‘Active’ designs stir a gain stage into the mix. Pre-amplifiers can also step-in to resolve impedance mismatches. If the output impedance of the source is (comparatively) high there will be incompatibility issues with some power amplifiers. This can result in ill-defined bass, vague imaging and rolled off highs. Pre-amplifiers have the potential to resolve such issues.

    There’s no doubt that the pot-less Metrum Hex requires pre-amplification. Ditto AURALiC’s Vega. Wait, wut? Yes, when lassoed to the Wyred4Sound mini monos the Vega gives up reasonable SPLs in the lower third of its volume range. Alas, this is where the least significant bit truncation of digital volume control eats a hole in musical information, the soundstage shrinks and tonal mass loses more weight the lower you go. AURALIiC co-founder Xuanqian Wang concedes: “If you are running mostly below 30 for serious listening, I would recommend a high quality pre-amplifier.”

    Resonessence Labs INVICTA Mirus is another of the many modern DACs to pack a volume control into its feature set. Thankfullt, it runs well into the upper third of its volume range, especially when the W4S monoblocks are direct-connectied to the lower voltage (2.3V) single ended outputs. Throughout the latter half of this year I’ve run the INVICTA Mirus RCA-to-RCA into the W4S twins more frequently than any other combination. It’s a combination that has become a bit of a 2013 reference.

    Each Wyred4Sound mAmp features a FET input buffer with a suitably high 100 kΩ input impedance whilst the output impedance of the INVICTA Mirus is a suitably low at 39 Ω. No impedance mismatch concerns here! Long cable runs can excacerbate impedance woes but, again and for emphasis, no problems here: I used one metre lengths of Zu Audio single-ended interconnects. Results were checked and double-checked with one meter XLR-terminated wires from Grave Science.

    In isolation, I had zero complaints about the sound mined by Resonessence Labs’ flagship DAC and the Wyred4Sound monos…but I was curious: would an intervening pre-amplifier bring anything to the table? Rather than dropping something price commensurate into the chain, I went large. I pushed deep into the high end: YBA’s Passion Pre500 retails for AU$10425. If there were no gain (pun intended) to be had from this $10k ‘active’ pre, game over.

    Prior to relaunching the brand in mid-2012, YBA’s French designer Yves Bernard André had been laying low for a couple of years. Financial and marketing muscle now comes from Chinese parent company Shanling. The Passion Pre500 is a beautifully engineered box. Heavy too. The elegantly fashioned remote control underscores YBA’s aesthetic elegance. However, this isn’t a review of the YBA itself. It’s a short investigation into product type relevance.

    With the YBA turning the original trio into a quartet, the deltas were startlingly obvious from the very first push of play.

    Firstly, the YBA built the soundstage bigger. MUCH bigger. In ALL directions. Secondly, detail retrieval went deeper, most clearly reflected in the greater grip of gut on string with the cello and double bass that drive forward the sinister swagger of Angelo Badalamenti’s “The Pink Room” (from Twin Peaks: Fire Walk With Me OST).

    The sparkle of low level super-micro dynamics within the depths of A Sagittariun’s “Crystallization” made for a more vivid take on hyperreality. In fact, it had me wondering if the matching YBA Passion 650 power amplifier might counterbalance the increased brilliance of Skittle-ish tonal colours. If you’re looking for a listening experience that you can sink into like an old armchair, the YBA’s amelioration (in the context of Wyred4Sound monoblocks) might not be for you.

    Lastly, the YBA Passion Pre500 fleshed out tonal mass (but not as much as I’d expected). This meant more metaphorical muscle and fat on top of the lean-ish – but emphatically not skeletal – frame already formed by the Resonessence Labs D/A converter. Picture a lean long-distance runner carbing up to become a 200m sprinter.

    This all points to the pre-amplifier holding tight to sonic relevance, even in systems fronted by a volume-controlling DAC. There’ll be more to come on this when I swap out the YBA pre for Wyred4Sound’s mAMP-matching mPRE in a day or so. Hang tight y’all.

    Further information: Wyred4Sound | Resonessence Labs | YBA

    Written by John

    John currently lives in Berlin where he creates videos and podcasts for Darko.Audio. He has previously contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

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