And you will want to use something suitable for the V70 power amplifier because it just may be the best amp the company has ever produced. I can't remember who noticed it first, but there's a belief in certain high-end circles that the best-sounding amps of all-time have tended to be sweet little 60-100 watters. Power doesn't enter into it, and you're faced with natural restrictions regarding speaker choice, but there's much to support that argument. Whatever, the V70 -- rated as '60W minimum continuous at 16 ohms from 15Hz to 20kHz -- is sized and priced ( 4299) as a middle-to-esoteric model, unable even to look at 2 ohm behemoths, nor can it fill a room much larger than 'normal' unless it's wired to a hypersensitive speaker such as a true horn.
Its power comes from eight KT90s (though I could have sworn that the review unit's tubes said 'KT91'), representing the latest generation of substitutes for the 6550 and KT88. And I'm mildly concerned about this profusion of KT-prefixed 'new' tubes. Why? Because Americans have embraced them with open arms while every UK tube maven I've spoken to has been cynical to say the least, with stories about container-loads of pre-Serb/Croat War Yugo-tubes needing to be cleared out of certain California warehouses. Suffice to say that the V70 sounded wonderful, so I don't give a toss what numbers appear on the glass. Amusingly, the company allows for tube substitutions with bias adjusted accordingly; alternatives listed include the 6550, 6550A, KT88 and KT100.
Using hybrid circuitry, Audio Research has produced this mid-power design as a lineal descendant of the Classic Series models of a couple years ago. In addition to using triode operation and ARC's cross-coupled circuitry, the V70 is balanced throughout. J-FETs make up the input section with MOSFET followers feeding 6FQ7 dual triodes directly driving the output valves. Soft-start switch-on and shut-off prevent any unwanted thumping; you're reminded of this by the 30-second delay which allows the tube heaters to rise to the correct voltage while the bias supply stabilises. Then there's a two-second 'ramp up' of the B+ supply voltage for normal operation; the sequence operates in reverse at switch-off for negligible strain on the tubes.
User interaction with the V70 is minimal. The fascia bears an on-off switch, flanked by tell-tales for power-on indicators (one of which flashes while the switch-on delay occurs) and fuse caps. At the back are the XLR inputs and screw terminals for the speakers, which ARC continues to prefer over binding posts. Your only intimate moments with the V70 will occur when you unpack it, unless your dealer has enough class to install it for you. The tubes are packed separately, along with a basic toolkit. Unscrew the cage, fit the numbered valves, connect the cooling fans and you're ready to rock. That's it.
Well, not quite. Even the solid-state DAC and line amp benefitted from a reasonable warm-up period, a good 30 minutes being sufficient. Amusingly, the gains over that first half-hour are minimal, and even ice-cold this set-up sounds special. The DAC2 betters its predecessor in one key area, that of delicacy and all it implies. Its benefits include clearer resolution of fine detail and ambience and some of the best '3D' I've ever heard. But be warned: the DAC2 is not an in-your-face performer and other DACs may be preferred for their greater weight and impact. What makes the DAC2 a stand-out among similarly-priced converters is its overall coherence; transistions from bass to mid to treble were smooth and consistent, with no change of character. And it's a natural for the LS3B, which possesses a nearly identical personality.
Even though this collection of components is being assessed as a system, I had to employ other devices for comparison's sake. Transports included the Krell MD20, the Marantz CD12 and -- for a laugh -- the transport section of the budget Marantz CD52 Mk IISE. Which acquitted itself beautifully, by the way. Although the LS3B sounded most comfortable when fed by the DAC2, interesting 'tailoring' was possible with the Vimak DS1800 DAC (greater impact) or the Krell Studio (richer, smoother lower registers), which I used as necessary...according to speaker selection. And this is important in the context of the V70, because it has extremely limited operating parameters. Which means limited speaker selection.
In a nutshell, the V70 hates low impedances. I assumed that the 4ohm Sonus Faber Minima Amator would prove a perfect mate. I was wrong. When the V70 clips, it sounds spongy, the bottom end falling apart before the treble. And with powerful bass from pieces such as Mel & Tim's 'Carry Me', the limits were reached even though the listening levels were far from Wayne's World suitability. So I moved to the Apogee Stage. Another mistake. Then the JBL L1. Sweet as a nut, but not quite up to the mark for resolving the imaging I heard the V70 yield through the Minimas. What to do?
Hmm...the spec sheet said 16 ohms. There's even a tap for this rarely-used impedance. And there, not three feet from my desk, are the LS3/5As. Dare I audition a 10k-plus system, less CD transport, with a speaker selling for under 500? The NBS cables used throughout cost more than the baby Beebs. Aah, what the hell. Who's it gonna upset?
Put another way: anyone who doesn't grin in admiration from ear to ear upon hearing the V70-plus-LS3/5A should go buy a Sega. Talk about sweet soul music -- Arthur Conley, where are you in this hour of need? Despite cabinets small enough to stack in the stockroom with Nikes and Reeboks, despite a basic design nearing its majority, the LS3/5As let the V70 work without worry, like not asking a road car to compete in a Grand Prix.
Plenty of level for this non-headbanger. Sympathetic lower registers. A friendly impedance. So much for the practicalities. But the sound? The midband was simply gorgeous, working so well with male and female vocals that I left the Starting All Over Again CD on repeat play for three hours. The girl-group backing in 'Wheelin' and Dealin'' came through loud and clear and positioned behind the frontmen. Off at an angle, no less. Moving to B.B. King's 'Don't Get Around Much Anymore', the system dealt with the wide dynamics despite specs which say that it just can't happen. Are we talking about miracles when a 2x60W tube amp and some tiny monitors put B.B. King right in your room?
I think not. Miracles have nothing to do with it. We're talking,
instead, about a package you're unlikely ever to be offered by a
conventional, nervous, tradition-bound retailer, a combination as
bizarre as a peanut-butter-and-banana sandwich. Which anyone who's ever
tried it will tell you is absolutely delicious. What this system
represents is true high-end performance without size penalties,
superlative use of digital hardware dovetailing with the romance of
tubes. There are other ways to spend five figures, most of which will be
regarded as more 'sane'; I reckon this ARC set-up will become something
of a fave with users of 'easy' electrostatics. But an ARC set-up with
LS3/5As is one that's guaranteed to bring a glow to your cheeks. And I
don't mean by having you rest your chin on the tube cage.