March 2005

ASL Phono LUX DT Tubed Phono Fun
Review By Jeff Rabin
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  On the face of it, a tubed phonostage makes about as much sense as the latest Christo installation in New York City's Central Park.

Tubes, as we all know, are inherently noisier and less suited to raising the vanishingly small signals that a cartridge makes to a level that a modern pre-amp wants than transistors. Moreover, tubes age far more quickly than anything made of silicon and with such aging tight tolerances are often thrown to the wind when they are asked to apply the following bit of RIAA math (or Comité Consultatif International des Radiocommunications for you Europeans out there) to the weensy-bitsy signal derived form trailing a rock through plastic:

Where:

N=level in dB
f=frequency
t1=treble time constant, 75uS
t2=medium time constant, 318uS
t3=bass time constant, 3180uS

And we know how much better silicon is at (digital) math. But here we're talking analog math, where amounts are never one or zero but somewhere in between. As such, while tubed phono-stages are easy to build, they are fiendishly hard to execute, but when properly made can sound glorious. The same invidious comparisons that I just made can of course be made between record players and vinyl and CD players and CDs. But I like vinyl and record players. I like tube based phonostages too. And when you combine the two, a certain vinyl-tubey magic — even if everything active down the line is solid-state and even if a tube phonostage is not the last word in accuracy or resolution — can bring a certain smile to my face almost unlike anything else in hi-fi. And in this, the ASL Phono LUX DT is no smiley-souled laggard.

For many years, my 'reference' (what I mean is, the one I like most and the one I use the most and the one I own) has been an EAR834P. Thanks MM. I have tried a few other outboard phono stages, from DACT, Musical Fidelity and NAD, and a few inboard of those vanishing species the pre-amp with a built in phono-stage, but it is tubed phono-stages that I always come back to.

My Beloved SW301: Two Arms, No Waiting!

Indeed, when my Garrard was out of commission getting a new arm and plinth, only the EAR would make my Revox even passably listenable. And for that to be true, something fishy had to be going on within its cookie-cutter box. The 'better' and more 'accurate' phono-stages simply revealed the Revox as the poor sounding, but built like a tank, linear tracker that it really is. The tube phono stage somehow enhanced that miserable table. And that can't be right, but sounded nice nonetheless.

Moreover, a valve phono-stage is probably about the most cost effective and inherently fuss-free way you can get that tubed sound that the hi-fi hacks wax so nostalgic about into your room. The tubes run forever, they are generally caged from prying, little fingers, you can swap tubes to your hearts content without picking up a soldering iron, and have little or no trouble driving inefficient or hard to drive speakers, because they don't. It was, therefore, with some glee that I opened the boxes on Antique Sound Labs (ASL) two cracking new phono-stages. I had already heard good things on the local Toronto Audiophile list about Antique Sound Lab's previous phono-stage The Mini Phono II, but photogenic it was not.

The latest iteration of the ASL phono-stage, the Phono LUX DT, is not quite the ugly duckling its predecessor was. The design is, indeed, something that I can see Darth Vader liking: two black metal boxes, the larger the phono-stage, the smaller the power supply connected by a locking umbilical cord. Round back there are a pair of quality gold plated RCA inputs and outputs and a decent binding post between. A rocker switch on the power supply lets there be light — so much LED blue light that I ended up turning the lights to face the wall with the jacks facing me. Can we please stop with the blue LEDs?

As Tash Gorka, head honcho at Divergent Technologies, the North American Importer of Antique Sound Labs, explained, the new ASL comes in two new flavors: a deluxe version which includes an extra tube as a buffer stage for those using passive pre-amps, and a less expensive version without the buffer stage for those with active pre-amps. Aside from tube count, they are by and large, identical. The manual is comprehensive in a way that a phono-stage manual can be and helpfully includes a full schematic with values, should repair or modification be desired, and is not without a few choice Sinologisms:

Trouble shooting: 

1. Power light not light — Check IEC power connector, Is it plug in to back Phono Lux DT and other connect to wall power socket? Check the fuse. [sic.]

However with these phono-preamps, if you should have a moving magnet cartridge, you are basically out of business unless you have a separate step up transformer. I imagine it will not be long before ASL offers one.

Luckily, I have been having great fun with an inexpensive moving magnet Goldring on my recently returned Garrard. The Goldring and the ASL got along like a pig in muck. Inevitably, there was some noise. It is tubed after all. But the noise was never intrusive.

With my pre-amp turned half way up driving a half a kilowatt solid-state amp into 93dB efficient speakers, not only could I hear the expected tube rush but I also seemed to be picking up the CBC. Someday I will star earth myself, but such conditions, however, are unlikely to be experienced under normal use and at normal listening levels. Only if I listened very closely could I hear any untoward noise and such noise is part and parcel of the valve game. So after spending about 3 quarters of a G of words of your reading life, how does the ASL phonostage sound? Thank you for asking. Very nice, actually.

Listen...

Out of the box and fired up from cold for, it had a very clear, lithe, quick, and not overly tube-like sound, though it was obviously hollow state.  In no way, however, could you say it sounded Vintage, as it is isn't and in no way could you mistake it for being solid-state either. It had that certain tube magic. Somewhat brighter than my dark sounding EAR, the ASL did not sound in any way that I would say was clinical, though it did appear to deliver everything on the record without unduly emphasizing the bad bits. The tight bass seemed a factor of the new Rega 300B arm I was using. The odd imaging a feature of the less than ideal temporary room setup. The black silence a function of my properly damped plinth with the bearing rumble a feature of my old turntable.

What I was hearing were, basically, the goods on offer in a nicely, replicable and coherent way. Limitations were more a function of the rest of my kit and room than of the phonostage. Bad eighties vinyl sounded like bad eighties vinyl. Overpriced audiophile reissues usually, but not always, sounded glorious. A change of mat and an addition of a heavy record clamp improved things, as expected.

This is not too say that the phono-stage was of the warts and all kind as their seemed to be a slightly, dare I say, soft focus to the proceedings. The Phono LUX DT is for playing Billie Holiday, not the Bad Brains. Comparison between Muddy Water's Folksinger on SACD and Vinyl showed the vinyl to throw a wider and more immersive soundstage. Whether or not this was an artifact of the phonostage artifact or due to a better-pressed record, I do not know. It was pleasant nonetheless and confirmed my faith in vinyl.

An audiophile reissue of Jimi Hendrix's Electric Ladyland, sadly with the second cover, sounded glorious in all its out of phase, weird imaging glory.  A nice find at a local flea market was an unplayed copy of the Risky Business soundtrack, which showed Tangerine Dream to be hypnotic as ever. Porsche, there is no substitute.

A lot of fun was had in this review by listening to an early eighties NAD/Unicorn test LP, complete with liner notes telling you what to listen for. Sure enough, I heard everything they asked. I then played this same LP with a NAD PP1 and the EAR, just to see where the ASL would slot in. I did not level match, so results would be conclusive, but I did find that the ASL (on purely subjective grounds) neatly slotted between the two, unusually reflecting their respective prices. Perhaps you do get what you pay for with phono-stages, an unusual circumstance in this hobby, and if that is the case, the ASL Phono LUX DT is good value.

One thing I did find a little odd was that I found the three-tube version of the phonostage slightly light in the bass, something my system usually delivers in spades. I had thought over time this might change, but it never did. I brought out some bass heavy EPs such as Yello's signature Ferris Bueller soundtrack song "Oh Yeah." What was nice, however, was how the ASL did not paint over the raunchy Led Zeppelin's Physical Graffiti, but at the same time preserved the grace of the Dead's Workingman's Dead with each drummer clearly heard and placed in a wide and immersive soundstage.

Rounding It Out

I suspect that the owner of an ASL would have a great deal of fun trying out different makes of tubes, listening for the difference, and choosing on the basis of taste. She could sweeten the top, extend the bottom, or enhance to an already nice midrange. Some particularly 'new old stock' (NOS) might even have it sounding vintage — particularly if the tubes were knackered and ready for the pull box.  I did not tube roll with the ASL but if I were to buy this phonostage it was certainly something I would do. Mil spec GE 5751s anyone?

I think the ASL phonostage would be a nice introduction to any system and particularly those who were interested in giving tubes a first try. And for those who are already smitten by tubes, the ASL will neither gild the lily nor sound out of place. It will not make badly recorded or pressed vinyl sound good, but when the vinyl going is good, this phono-stage will get going. My only real complaint has to do the startling bright blue LEDs and that's not much to complain about at all.

Specifications

Type: Moving magnet (MM) phono stage

Frequency Response: 20 Hz to 20kHz

Phono Input Sensitivity: 8.3mv

Phono Input Impedance: 47Kohms

Nominal Voltage Gain: 41dB

Output Impedance: 15Kohms

Signal To Noise: 74dB (2mv)

Total Harmonic Distortion: 0.2% (at 1V output)

Chassis Finishing: Black

Shipping Dimensions: 330 x 200 x 250 (HxWxD in mm)

Weight: 3 kgs.

Price: Phono Lux DT $445

Company Information

Divergent Technologies
342 Frederick Street
Kitchener, Ontario
CANADA N2H 2N9

Voice: (519) 749-1565
Fax: (519) 749-2863
Website: www.divertech.com