Audio Research LS15 Review

by James Leahy

                                                                     Introduction

 

The LS15 was introduced in 1996 by Audio Research. It is a line level pre-amplifier only and features remote control function as standard. There are two Balanced outputs and two Balanced inputs included also along with Single Ended input and outputs for all sources. The LS15 features Audio Research's trade mark slim line handles on the unit's front face and it's appearance is timeless.

There is no Balance Control on the LS15 which might make it a deal breaker for some but in my listening room I have never felt I needed to compensate for acoustical inadequacies.

 

 

My testing has shown the Balanced circuitry in the LS15 to add considerable benefits if your components have the capacity to do so. The LS15 uses solid metal RCA connectors that are of excellent quality just like every other Audio Research product in their line-up.

This pre-amplifier is a 'direct path' unit without tone controls like some many other Audio Research pre-amplifiers before and after this model. Discrete circuitry, including polypropylene capacitors and metal-film resistors, are used throughout.

 

Most Audiophiles have noticed by now that the first stages in a system seem to be the most important as far as distortion is concerned. A tiny amount of distortion that would be virtually undetectable in the latter stages of a power amplifier appears to add entirely disproportionate amounts of hardness and edge to string tone and mis-tracking distortion when it originates in the preamp stages. This is why the LS15 circuit is so critical.

 

 

As can be seen, (pic left) the LS15 features four 6922 tubes and it's circuit is an uncluttered well laid out affair with a well built and carefully selected power supply with extensive filtering. Prior to any testing I re-tubes this pre-amplifier with the afore mentioned tubes and let warm up for 60 minutes.

I have found that the stock Electro-Harmonix 6922's to be the best for the LS15 and these are the factory tubes that Audio Research use in this pre-amplifier. I have had many customers switching brands with inferior results.

 

 

                                     Sonic Evaluations

The review record of choice today is Fleetwood Mac's - Heroes Are Hard To Find (WEA Records, 1974). The LS15 is perhaps a bit too rich and warm in the transition area between bass and midrange for my VT200 Mk.I, and also it was just a bit short in the highs. Not really doing anything right. The sound is slightly soft and with a definite lack of drive. This pre-amplifier is very laid back with a hazy presentation. Probably why it matched up very well with my VT100 Mk.III. They even each other out nicely. This pre-amplifier would suit amplifiers that are more on the detailed side of warm rather then lush. The soundstage has less apparent depth and certainly width with most records then I had expected. It has  transparency and dynamic life in soft passages but a lack of dynamics on a whole and and weak bass extension. The top end also didn't sound completely neutral, but it didn't get in the way of the music.

If I had to guess, I'd say that it was way down at the very top end, and that the lower treble was maybe a touch elevated with respect to the upper midrange. Cymbals were clear, and their overtones seemed to go on forever, eventually fading breathily into the hall's far reaches. On the other hand, perhaps their metallic shimmer wasn't quite as airy as it can be, and didn't permeate the surrounding air to the same degree as I have heard on my reference Audio Research LS26 pre-amplifier. The LS15 is no where near what the new LS26 can produce in terms of the three D's. Namely, definition, dynamics and drive. Do not let anyone fool you into thinking it is. I have had to listen to more Audiophiles than I care to remember ring me up and rap on about how much better the early Audio Research pre-amplifiers sound in relation to the new current models and I must say I disagree 100%. Most of these guys haven't heard the new models for a start so how they can give an unbiased opinion is beyond me. Let alone done any A-B testing.

Audio Research have made quantum leaps in regards to soundstage dynamics and definition in the last few years. The difference is quite frightening to anyone who has heard both on their system and is willing to give an honest review.

 

 

Associated review Equipment

  • Amplifiers:         Audio Research VT200 Mk.I
                            Audio Research VT100 Mk.III

  • Phono Stage:      Audio Research PH5

  • Speakers:           ScanSpeak & Vifa Custom

  • Cables:              Neotech

  • Cartridge:           Ortofon MC Jubilee

  • Subwoofer:         Velodyne HGS-15

  • CP Player:          Sony SCD-XA777ES