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Equipment Review
June 2007

Audio Research LS17 Preamplifier

by John Crossett



"… a benchmark in its price class."

Reviewers' Choice Logo

 


 

Review Summary
Sound "There was a tactile realness and a distinct sense of the recording venue, along with deep, tight bass. Its highs seemed to extend into the stratosphere, allowing for great portrayal of space -- which showed ample layering and depth -- together with abundant detail. The LS17 does subtract one thing I’d become used to with the SP16: There’s less of that classic tube sound. The midrange is still richly reproduced -- after all, the LS17 still uses tubes -- but now it’s far more neutral."
Features "The LS17 is a [remote-controlled] hybrid [line-stage-only] preamp. It uses JFets in its input and gain stages and a pair of 6H30P tubes in its output stage…. The 6H30P (or 'super tube' as it's been unofficially dubbed) is supposed to be not only sonically superior but long lasting as well -- which sounds like a win-win situation to me. The LS17 has a solid-state power supply with separate electronically regulated low-and high-voltage supplies."
Use "I also used the LS17 both single-ended and balanced, and the results were clearly in favor of the latter…. In considering the LS17 as a potential upgrade, do not discount having the option of going balanced, especially if your source is balanced. Balanced connection can improve the sound of your audio system in ways that a mere equipment upgrade can't."
Value "While using the word 'bargain' to describe a $4000 preamp may be a tad presumptuous, within its price range, the LS17 is exactly that. You’ll find yourself having to pay more money for less than what the LS17 offers."

There is an old saw that runs: "You never know what you’ve got till it’s gone." The use of this expression is usually in the field of romance, but it has its application in the audio arena as well. There are many times when we replace a long-cherished part of our system with what is supposed to be an upgrade, only to rue the day we did it, discovering that we didn’t really appreciate what we had.

On the flip side of this same coin is discovering that what we had long considered excellent sound was, in reality, ape waste in comparison to the sense of sonic bliss we achieve with a new component. We may find that aspects that are now gone -- things like noise, frequency-response aberrations, and the masking of micro or macro detail -- had a greater effect on the sonic outcome than we thought, and that new preamp, CD player, cartridge, speaker or whatever works audio miracles.

So it was when I began to listen to the Audio Research LS17 line-stage preamp. I had been living in blissful happiness with the ARC SP16 for many years. I thoroughly enjoyed the manner in which it reproduced music in my system. I thought I knew what I had -- and was happily groovin’ on the music it reproduced. But after inserting the LS17 into my system -- right out of the box and stone cold -- I was aghast at how much more musical information was coming through the speakers. I know, I know -- I should have given the LS17 proper burn-in before giving it a serious listen. But even we so-called "audio professionals" have been known to be tempted by the new, the updated, the upgrade. The LS17 demonstrated to me quite quickly that what I thought I’d been hearing was not all that my LPs, CDs and SACDs were capable of delivering. All of a sudden, my audio system took a giant step forward on that mythical journey of reproducing the sound of live music at home. Talk about teaching an old dog a new trick!

The devil in the details

The $3995 USD LS17 looks like the classic Audio Research preamps of yore with its silver faceplate, black rack handles and twin knobs. It is the latest in a long line of "LS" -- "line-stage" -- preamps from the Minnesota-based bastion of tube audio, joining the LS26 as a current product. It stands 19" wide, 5 1/4" high and 12" deep and weighs a decent 13 pounds. It can be ordered in either ARC classic silver or basic black, with or without handles. (Why anyone would want an Audio Research product in black and without the handles is beyond me.) The two knobs control volume -- in 104 steps -- and input. Below these and along the bottom of the faceplate are four pushbuttons for Power, Monitor, Processor, and Mute. All functions are duplicated on the nicely sized remote control. There is a larger rectangular area above with a green linear LED display to indicate the preamp's operating status -- input chosen, volume level and the like.

Around back the LS17 has two sets of balanced and five sets of single-ended inputs -- though two of the latter are for the processor loop and tape monitor. There are also twin balanced and single-ended outputs, so using a subwoofer with the LS17 will be a walk in the proverbial park. There is also a fuse holder (note the fuse's orientation if you remove it -- ARC pays attention to such things), a 12-volt trigger input, and an IEC power-cord receptacle.

The LS17 is a hybrid preamp. It uses JFets in its input and gain stages and a pair of 6H30P tubes in its output stage. The 6H30P (or "super tube" as it's been unofficially dubbed) is supposed to be not only sonically superior but long lasting as well -- which sounds like a win-win situation to me. The LS17 has a solid-state power supply with separate electronically regulated low-and high-voltage supplies.

Voltage gain is 18dB balanced and 12dB single-ended, indicating that the LS17 is indeed fully balanced. The LS17 does not invert polarity -- no futzing with speaker cables required.

What I heard

The LS17 was like John Wayne: unflappable, cocksure, authoritative and quietly powerful. There was a tactile realness and a distinct sense of the recording venue, along with deep, tight bass. Its highs seemed to extend into the stratosphere, allowing for great portrayal of space -- which showed ample layering and depth -- together with abundant detail. The LS17 does subtract one thing I’d become used to with the SP16: There’s less of that classic tube sound. The midrange is still richly reproduced -- after all, the LS17 still uses tubes -- but now it’s far more neutral. If I’m going to have to lose something in the exchange, that loss of tubey colorations would be what I would have chosen.

One of my favorite jazz recordings is the soundtrack to Robert Altman’s movie Kansas City [Verve 314 529 554-2], and it's beautifully recorded. Through the LS17, I felt as though I understood the soundstage for the first time. I wasn't just peering into it from the outside. I could sit back, close my eyes and revel in the honest sound of all the instruments -- not only in their placement, though that was possible, but in their individual sonic signatures. I also had a solid sense of each instrument in a very spacious soundstage, yet all of this was only the opening epiphany.

With the LS17, there was real bite to trumpets and body to brass. Bass and drums had power, and piano was realistically sized. With the SACD of Ray Brown’s Soular Energy [Groove Note/Concord GRV1015-3], Brown’s big acoustic bass -- the star of this particular show -- was tight, full, big, and seemed to go a few Hertz deeper than I was used to. Pitch definition took a giant step forward. I felt like I was in the company of a real standup acoustic bass being caressed into life by one of the true jazz masters of the instrument, not listening to a mere reproduction.

Associated Equipment

Loudspeakers – Magnepan MG1.6/QR.

Power amplifier – Bryston 4B SST.

Preamplifier - Audio Research SP16 with internal phono stage, Conrad-Johnson PV15.

Analog - VPI HW-19 Mk IV turntable with TNT platter and bearing, Super Arm Board, VPI/Rega VTA adjuster, and VPI dropped counterweight; Butternut Audio-Modified Rega RB300 tonearm; Clearaudio Maestro cartridge.

Digital sources – Marantz SA8260 CD/SACD player, Stello CDA320 CD player/DAC, Panasonic DVD-F65 CD/DVD-V/DVD-A player, Yamaha DVD-S657 universal player, Oppo DV-981HD universal player.

Interconnects – Analysis Plus Solo Crystal Oval and Copper Oval-In, Alpha-Core/Goertz TQ2.

Speaker cables – Analysis Plus Solo Crystal Oval and Oval 9, Alpha Core MI2.

Digital cables – DH Labs D-75 coaxial cable, Monster Cable and DH Labs TosLink cables.

Power cords  – Harmonic Technology Pro AC-11.

Power conditioner – Monster HTS-1000.

Accessories - Salamander Archetype racks; Symposium Roller Blocks, Ultra Platform, Svelte Shelves, Isis shelf, Fat Padz and Roller Block Jr.

If you want to hear what an audiophile means when he says a singer is "in the room" then pluck Holly Cole’s Don’t Smoke In Bed CD [Alert Z2 81020] from your collection and play it through the LS17. Right from David Piltch’s opening bass line you can close your eyes and hear everything, especially Cole’s voice, right there in front of you all dimensional and real. This was, without a doubt, the finest playback of this disc I’ve ever heard in my listening room.

Dynamics are another strong point of the LS17. When Roy Orbison sings from soft and gentle to full throttle on the final verse of "Mean Woman Blues" from the LP The All Time Greatest Hits of Roy Orbison [S&P (2) 507], it brought me right out of my seat. The LS17 never skipped a beat, sailing right on through. This bears testimony to both the size and quality of the LS17’s beef-up power supply. You don’t get thrills like these from components with poorly designed power supplies, and Audio Research certainly didn’t skimp on the one inside the LS17. This is one of those hidden assets that you get for your money. It goes unnoticed until you start listening.

You might conclude from everything I've noted so far that the LS17 is nigh-on perfect. Like so many of its peers, it has its share of limitations -- you can't expect everything for its price. For instance, it doesn't offer the widest or deepest soundstage I've heard, nor does it sound as three-dimensional as the best preamps on the market. It also lacks the ultimate sparkle and extension on top as well as the fullest authority on the bottom. While it is very quiet, it does not have the purest, blackest, most silent background, nor does it dredge up every last scrap of detail. Despite all of this, the LS17 is so cannily balanced, so well conceived, you may fail to notice what it doesn't do in an ultimate sense. Like John Wayne, its faults only make it more human, and therefore more easily taken to heart. If you want only the very best from Audio Research, it’s out there. They call it the Reference 3, and it will give you everything the LS17 lacks. It will also cost you more than twice as much.

There is room for improving the LS17 with well-chosen tweaks. The folks at ARC stress the quality of the power cord they include with their products, claiming that using an aftermarket may not necessarily be an upgrade. True? Yep, at least for some of the LS17’s potential customer base. Audiophile that I am, though, I couldn’t help but try my power cord of choice, the Harmonic Technology Pro AC-11. Did I hear an improvement? Yep, though it wasn't nearly as significant as when I replaced the stock cord of the SP16 with the AC-11. But listening to the mix of acoustic and electric instruments on the Soul Farm CD Scream of the Crop [Desert Rock Records 26-6] with the AC-11, I heard the LS17 more easily sort out the instruments in the mix.

Audio Research also put some thought into what's beneath the LS17 -- its squishy black footers, which ideally exclude the need for aftermarket footers. ARC suggests that setting the LS17 on a good, solid surface will get the best out of it. I discovered that I could hear most of what the LS17 offered when it was used just as ARC suggested -- au natural. But when I slipped Symposium Roller Block Series 2+ footers and a Svelte Shelf below, the LS17 improved noticeably -- enough that I wanted to keep it all together. With Mobile Fidelity's very first SACD, Duke Ellington’s Blues In Orbit [UDCD 757], there was more weight to Ellington’s piano and more of that tinkly sound Ellington mastered when the Symposium products were under the LS17. The rhythm section had more definition and heft, and the orchestra more weight and power. The entire presentation took on a richer, more detailed and clearer picture than without the Symposium goodies. If you can’t afford the LS17 and all the added accoutrements, fear not -- your money will not be misspent on only the LS17. It’s just that you’ll squeeze out every last iota of performance should you judiciously add some aftermarket accessories.

I also used the LS17 both single-ended and balanced, and the results were clearly in favor of the latter. I can't lay all of the praise on the LS17, though. My Stello CDA320 CD player is fully balanced, which gives it a distinct advantage when connected via its XLR outputs. Indeed, with levels matched as closely as possible, single-ended connection sounded slightly softer -- perhaps the better word would be "muffled" -- in comparison to balanced use. In considering the LS17 as a potential upgrade, do not discount having the option of going balanced, especially if your source is balanced. Balanced connection can improve the sound of your audio system in ways that a mere equipment upgrade can't.

Comparisons

In sonic terms, the LS17 is head and shoulders above my beloved Audio Research SP16 ($2495 in line-stage version). It did everything the SP16 did and bettered it by a considerable margin. Now that statement may raise a few eyebrows; for the $1500 price difference, one should expect the LS17 to be better. But there’s better and then there’s better. The LS17 is better.

At both frequency extremes the LS17 has it all over the SP16. Through the midrange the SP16, with its tubier sound, was delightful to listen to, but the LS17 offered a touch of lush, creamy tube sound while managing to remain far more neutral, honest and even-handed. It also extracted more macro and micro detail. Width and depth were both far more realistically reproduced via the LS17 as well. Finally, the SP16 is single ended only, and having the option of both balanced input and output is a far bigger deal than many of us used to only single-ended connection can fathom.

I also had the Conrad-Johnson PV15 ($3000) during part of the review period. This provided me with yet another option for comparison to the LS17. Yes, the PV15 is also a less costly piece, and it is also single ended only. But its strengths are such that it was more competitive with the LS17 in some ways than the SP16. The PV15 is also a tube design that does not revert to sounding tubey. It does a better job at the frequency extremes than the SP16 while still coming up short of the extension and weight of the LS17. There’s simply more detail, definition and extension, and a tactile sense of realness with the LS17. The PV15 gets you part of the way there, but the LS17 takes you the rest of the way home.

The Audio Research SP16 and the Conrad-Johnson PV15 are both fine preamps, especially at their prices. The SP16 was a Reviewers' Choice and the Exceptional Value award winner for 2002. But comparing these two fine preamps to the LS17 is truly a case of more and better: more dollars spent and better sound quality as the result. The LS17 was the superior music reproducer and more than simply an evolutionary step forward from the SP16. Given my experience, it’s an entirely new species of ARC music-making machine.

Conclusion

Audio Research calls the LS17 its "Baby Ref" line-stage preamp, and I believe there's some truth here. While I’ve not heard the Reference 3 in my system, with the LS17 ARC has packaged quite a bit of sonic punch into what is a mid-priced preamp. Plus, just try to find another tube line stage that offers truly balanced inputs and outputs along with the LS17’s sonic strengths for the same price. That’s not going to be an easy task. While using the word "bargain" to describe a $4000 preamp may be a tad presumptuous, within its price range, the LS17 is exactly that. You’ll find yourself having to pay more money for less than what the LS17 offers.

So while the LS17 is inherently better than its less costly stable-mate and more than likely not its big brother's sonic equal, it is still a benchmark in its price class. Its attributes are addictive and its limitations pass almost unnoticed. Once you’ve heard its siren's song, you’ll find yourself drawn unerringly to its beguiling presentation. And best of all, "You never know what you’ve got till it’s gone" won't apply to the LS17 -- it's certainly not leaving my equipment rack.

...John Crossett
johnc@soundstage.com

Audio Research LS17 Preamplifier
Price:
$3995 USD.
Warranty: Three years parts and labor.

Audio Research Corporation
3900 Annapolis Lane North
Plymouth, Minnesota 55447
Phone: (763) 577-9700
Fax: (763) 577-0323

Website: www.audioresearch.com

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