I was the proud owner of an LS15. It was just fine, but I needed a balance control for the psychoacoustics of my imperfect hearing. The LS25 fit the bill. If you LS 15 fans can possibly imagine better sound staging and "tube feel" that's the LS25 in a nut shell.
I've discussed this feeling with ARC and other audiophile compulsives. They all concur that this model is more a watered down Ref One rather than an enhanced LS 15. Regardless, they all sound great or ridiculously great. I guess you might read into my short and sweet review that I am a real advocate of tubed preamps. I believe there is less freedom of choice in power amps. Power amps are more closely determined by your speakers.

accurate, neutral,deep soundstage,fast bass

nothing

Best preamp what i have ever own.very fast and accurate,neutral, my system is sphinx project 32 cd player, ar ls 25 preamp and gamut amazing d 250 monoblocks,siltech gold-silver cables and very accurate and neutral acapella campanile horn speakers with plasma tweeter.AR ls 25 sound very good this compination.ar is i think best

Similar Products Used:

ls 16,sphinx project 8

Very dynamic, extended frequency extremes but not fatiguing or etched on the top end.

Slight hardness in the upper mid-range compared to the best traditional tubed electronics.

I purchased the LS-25 about two months ago after auditoning the Herron, Hoveland, BAT and Pass preamps in my home. I had owned the Michael Yee unit for many years. First let me say that I think it is stupid to give a component a rating of "5 stars." So my take my 4 star rating in that context. The LS-25 met my criteria for accuracy, dynamics and soundstaging. It produces a terrifically wide and deep soundstage and the images on that stage have great body and weight. This was also true of the Herron and the Hoveland units, but they softened transients more than I thought was accurate. The Herron and Hoveland units were VERY pleasing to listen to, but I just felt that they were more euphonic than I cared for. The LS-25 also "rounds" out the sound and images more than the BAT, Pass or Michael Yee preamps, but only just slightly so. Trumpet, french horn, trombone have have just that perfect bite to them. Back to the soundstage/imaging... the ability to get layers of depth in the soundstage was the best of the units that I auditioned. On good recordings this aspect of the LS-25s performance is tremendously satisfying. In my room, the images don't extend forward in front of the speakers, but none of the units that I auditoned were able to create that illusion. More likely due to my speakers and room.

The LS-25 remote works perfectly, and the unit has been utterly reliable. Also, Audio Research is likely to be around for ever. Over all, a great product at the price point. Much better value than some others in this price range, but not cheap. Certainly not a cost no object effort, but a significant step toward that end at a sensible price.

BTW - speakers are custom dynamic speakers made by Brian Daley, bi-wired and bi-amped with Michael Yee Audio PA-2s. Front end is SOTA Millennia, Graham, Grado Statement and Herron Audio phono preamp. CD source is Rega Jupiter CD transport and Michael Yee Audio D to A.

Similar Products Used:

Herron, Hoveland, Pass X-1, BAT VK-50 & Michael Yee preamps.

Midrange Detail, silky smooth top end, quiet, remote

I'm still looking

Detailed, slightly dry midrange with a wide 3D soundstage, excellent transients, spectacular top end that's not rolled off with a quick tight bass response. Typical Audio research look and feel, attention to detail, built like a tank, will probably live forever. Midrange tones such as vocals are top dead center accurate. Bass is tight and well extended, but a touch dry or lean at the higher bass frequencies. The most transparent, silky smooth top end I've ever heard. The detail is above approach, if there's a weak link in your system or in the source material the LS25 MII is ruthless in revealing these shortcomings. I recommend a slightly warm and rich sounding speakers such as Vandersteens. Stay away from dry detailed speakers such as Thiels.
My equipment consists of; Counterpoint SA-20 Amp, AR LS25 MII preamp, AR PH3 Phono stage, Nakamichi OMS 7II CD player, Vandersteen 3A Signatures w/2WQ Sub. Denon 62L T/T with Denon 103MC and Wire World interconnects.

Similar Products Used:

LS17, Hovland

After almost 20 years of search, I finally made my dream come true: I brought back home an ARC LS 25 with a VT 100 MK II.
What can I tell except that I now have real live music at home and that all my components disapeared behind it...

These two components are really magical and you can't decide yourself to stop theim even after hours of listening. Thanks to the Audio Research team, hoping they will make us come our dream alive for a long time.

My current system:
ARC VT 100 MK II amplifier
ARC LS 25 preamplifier
STAX Quattro II CD Player
JEAN MARIE REYNAUD OFFRANDE speakers

Sweet mids and highs

A barely noticeable loss in the bottom end

I had for more than a year been using a Wadia850 straight to a Mark Levinson 333.5 amp to Aerial 10T's. The sound in this setup is very detailed and analytical. The punch across the whole sound spectrum is amayzing. But because of having the direct connect the system was very unflexible for new media so I decided to checkout a good preamp.

Without a doubt the ML No.32 Reference is just unbelievable in quality but at $15k a little out of reach. I tested the Audio Research LS25 at suggestion of the dealer. He mentioned that a new model of the LS25 with only 2 tubes was out and that the sound rivaled the Ref.2.

Took it home for a demo. This was a difficult thing to compare to a Wadia850 direct to AMP ( to match volume levels). So I had to use a SPL meter to get the right setup. After getting this done, It was a pleasureable couple of days of listening to music.

All in all, what was amayzing of the LS25 was the sweet liquid tube sound surrounded in the mids and highs. It stripped away a harshness in the upper region in the direct to amp setup I had. The mids became also very musical and had a sweetness to them that was enchanting. The lower end was a little more muddy than the direct setup, but that was expected. Also the system didn't have the same slam to it as before. But that is something I will correct latter.

If you haven't checked out the new LS25 two tube version, take it for a spin. It's relativly new and there web site as of today still only mentions the 4 tube version.

The people at the dealer say that the difference between the 4 tube version and the 3 tube version is incredible and the sound is rivaling the Ref.2 for wich AR is actually supposedly working on revamping the Ref.2 for this new tube design.

A must try and for me it was certainly a must BUY.

The ARC LS 25 fits seamlessly into my professional studio environment! The unit is liquid and transparent, perfect for my Reference Playback requirements.
Ironically, I have been using Solid State at this stage, purely from a reliability standpoint. When I found this fully balanced beauty, I auditioned it at my studio and was immediately aware of the "veil" lifting and the sound being reproduced as it was originally perceived at the point of capture.
All this for less than the price of one Neumann 149 tube microphone (let alone a standard matched pair)!
Amazing.