Tube Preamp Reviews

Two August 2021 FollowUp Reviews

John Atkinson  |  Aug 2, 2021

Stereophile's August 2021 issue contained further looks and listens to two high-performance products: the Audio Research REF 6SE line preamplifier and the AudioQuest Niagara 3000 Low-Z Power Noise-Dissipation System.

In his November 2020 review, Jason Victor Serinus found that Audio Research's REF 6SE tubed preamplifier $17,000 was very sensitive to system tuning. John Atkinson took a listen to the REF 6SE and compared it with three topnotch preamplifiers: the MBL N11 ($14,600), the Pass Labs XP-32 ($17,500), and the Benchmark LA4 ($2599). He decided that the Audio Research was indeed a superb-measuring and superb-sounding preamplifier, but noted that its sonic signature would work best with systems that were a little laid-back in the upper midrange and that didn't have underdamped or poorly defined low frequencies.

"But, as to why the REF 6SE sounded the way it did in Jason's system, I don't have a measured clue," he concluded!

AudioQuest's Niagara range of AC power conditioners, designed by Garth Powell, have consistently impressed Stereophile's reviewers and the Niagara 3000 was no exception when Tom Gibbs reviewed it in January 2021. Fred Kaplan had felt for a long time that he didn't have a need for power conditioning but after trying the $2995 Niagara 3000, he experienced an epiphany: he learned from his experience with a conditioner that was in his budget ballpark was that "AC power is a nightmare, grounding is a nightmare, noise from anything and everything that's plugged into a socket is a nightmare. The Niagara 3000 or any of these other devices won't make your stereo system better than it already is, but to make it sound as good as it's capable of sounding, you probably need something that clears out the electronic gremlins, unless your power is already pristine, which isn't likely." Fred bought the review sample!

COMMENTS
Old Audiophile's picture
Submitted by Old Audiophile on August 2, 2021 - 1:59pm

Always a pleasure reading your reviews and perusing the measurements!

Line hash, as I think it's sometimes referred to, has always been an intriguing subject, to me. I've been using and old (i.e. circa 2001 or thereabouts) modestly-priced (i.e. about 2 or 3 hundred U.S. dollars, back then) Monster power conditioner for a long time. Occasionally, I wonder about replacing or upgrading it. However, any step in that direction would mean a significant cash outlay for something that, to me, might not result in an audible improvement or, at best, a very slightly noticeable improvement. This would be money I would ordinarily spend on music. Is it reasonable (or not, as the case may be) to assume that if one lives in a sparsely populated rural area (i.e. 1,800 souls) with well cared for power lines, faithful electrical service and in a dwelling built in 1985, that sophisticated power conditioning would produce a significant cost-effective return on investment? My nearest neighbors are a quarter mile away. My house is not festooned with all manner of electric or electronic gizmos; just the basic appliances, most of which aren't in use when music is playing, anyway. I'm wondering if, comparatively speaking, line conditioning might be more of an issue for city dwellers or larger sub-urban settings. We hardly ever experience power surges or drops out here in the boonies and that generally only happens during thunder & lightening storms when the stereo gets shut down, anyway. Just curious.

John Atkinson's picture
Submitted by John Atkinson on August 3, 2021 - 3:51pm
Old Audiophile wrote:
Always a pleasure reading your reviews and perusing the measurements!

Thank you.

Old Audiophile wrote:
Is it reasonable (or not, as the case may be) to assume that if one lives in a sparsely populated rural area (i.e. 1,800 souls) with well cared for power lines, faithful electrical service and in a dwelling built in 1985, that sophisticated power conditioning would produce a significant cost-effective return on investment?

Reasonable, yes, especially if your audio system is provided AC power by a dedicated line from the breaker box. I would also recommend making sure that the AC ground in your system is as low-impedance as possible.

Michael Fremer will be writing about this in his November 2021 Analog Corner column.

John Atkinson
Technical Editor, Stereophile

Charles E Flynn's picture
Submitted by Charles E Flynn on August 3, 2021 - 5:41pm

I would like to see Mr. Fremer or another of Stereophile's authors investigate whether there is anything we should know about service entrance cables and main electrical panels. Are there any developments in either of these areas that we should know about, either from an audiophile perspective, or just one that appreciates good engineering?

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on August 5, 2021 - 10:42am

I do not know of upgraded electrical panels - I'd love to know if they exist - but we did change to fresh circuit breakers when we installed an 8 gauge dedicated line to the music room. Alas, because the music room is in a detached building, WA state requires two circuit breakers, one in the house itself and one in the music room. We minimized noise on the line by moving the circuit breaker in the house panel to the top of its row. We also spoke with the city, had the transformer that feeds five houses including ours checked, and ended up with a new and more powerful transformer. All this has made a difference.

Charles E Flynn's picture
Submitted by Charles E Flynn on August 5, 2021 - 11:10am

Mr. Serinus,

Thanks for the interesting details about your installation. The 8 gauge wiring should help with instantaneous peak current. I have seen no other mention of having the circuit breaker for the dedicated line at the top of the panel. It does make sense.

I hope you will be able to review this new recording:

https://www.psaudio.com/products/bach-cello-suites/

Jason Victor Serinus's picture
Submitted by Jason Victor Serinus on August 5, 2021 - 2:10pm

Hi Charles,

Thanks to Frank Doris, I do have the DSD files. In addition, Thomas Moore, whose Five/Four Productions team worked on the recording, is sending the SACD. Whether I will be drawn to review it is unknown at this time. Lots on my plate... But your request is important. Thank you for it.

jason

Charles E Flynn's picture
Submitted by Charles E Flynn on August 5, 2021 - 2:17pm

Mr. Serinus,

You are welcome, and it is good to know that this recording will get the attention it deserves from Stereophile.

MauriceRon's picture
Submitted by MauriceRon on August 4, 2021 - 2:46am

i have a connected coment...if we see noise is a problem on AC power lines why do so meny stereophile fans (like archimaralago) say this same problem canot be found inside PC's used for streeming ?

hb72's picture
Submitted by hb72 on August 7, 2021 - 11:55pm

I guess this is the fundamental difference between digital and analog: digital equipment is somewhat less susceptible to noise except for some forms of noise (jitter comes to mind) and as long as we consider only digital domain - which in itself is abstracted, or, to be more precise, interpreted from electric domain (which clearly is susceptible to all sorts of noise).
Whether or not this suggest to best shift the digital/analog boundaries (speakers work analog) right into the speakers I cannot say. Active speakers with D-class amps are successful (think of KEF LS50 W, or some super expensive B&Os reviewed here), but its perhaps less fun with tinkering.

TNtransplant's picture
Submitted by TNtransplant on August 9, 2021 - 9:56pm

Ironic that these two follow-ups are together as I found that the combination of ARC REF6 Pre (not SE upgraded) and the AQ Niagara 7000 had a hum issue that was not present with power conditioners from Shunyata or Vibex.

Not sure why -- and admittedly have heard the pairing at shows with fine sound -- but for some reason in my system the two components did not play well together regardless if the ARC was plugged into High Current or Ultra-Linear banks.

(Should note that using exclusively the HC banks on an AQ Niagara 5000 for my back-end tube power amp & powered Vandersteen speakers is working well.)

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