Stereo Amplifier

Review: Luxman LV-103 Stereo Amplifier

Extreme as it may seem in these days of the fantastically complex and capable integrated circuit technology which has put solid-state time on our wrists and sent men to the moon, the good old 'steam' valve still holds a place dear to the hearts of a small, but by no means insignificant, minority of audio enthusiasts. One might write-off this loyalty as a refusal to be realistic and move with the times were it not for the fact that for whatever reasons systems based around valve amplifiers regularly demonstrate that elusive, ear-warming, 'sing-along' quality that hi-fi fanatics somewhat unfortunately term "musicality" (unfortunate because it is hard to accept that any piece of hardware can be possessed of such inherently animate characteristics). The effect may owe less to complete accuracy and more to the inclusion of small amounts of innocuous-sounding even-harmonic distortion, to the more graceful overload characteristics of valve amplification stages, to the impedance matching control exerted by optimally-designed output transformers or whatever, but few who have heard a good valve-based system will argue with its more ingratiating qualities.

One thing which remains true after all these years is that it is easier to design a respectable sounding valve amplifier of modest power rating than an equivalent using transistors. Valves are inherently more linear than transistors, headroom limitations more or less disappear and because they are voltage rather than current operated they pose less signal-related demands on the power supply. All in all, valve circuits can be very much simpler, which is usually a good thing, and if loudspeakers were also voltage rather than current driven the case for using valves would be pretty well un answerable. But because they are not, expensive impedance matching output transformers have to be employed to juggle with Ohms law and manage the final voltage-to-current conversion.

On the face of it, then, Luxman's Brid integrated amplifiers (Brid being short for hybrid) would seem to offer the best of both worlds. Their socalled pre-driver (or line level) stages are valve based with the speaker output muscle provided by Mosfet solidstate devices, which are very effective voltage to current devices. The hyper-critical phono inputs also use FET transistors in their gain and equalization circuitry.

There are two amplifiers in the Brid range at present, this LV-103 model which offers some 65 Watts per channel (for 8 Ohm loading) and a bigger brother, the LV-105 which gives 85 Wpc (again for 8 Ohm loading). Matching these are an AM/FM tuner, the T-105 and a Compact Disc player, the D-105, although I can't really imagine that the latter sport s much in the way or a valve complement!

Facilities and construction

The LV-103 has inputs labelled for phono (switchable between moving-magnet and moving-coil), tuner, CD, AV/aux and two audio tape machines with full dubbing. AV/aux simply means that the audio channels (play and record) of a video machine can be connected here or that the input can be used alternatively as another spare line-level input for some other audio device. (The LV-105 caters additionally for the video signals and also for a second Audio/ visual set-up.) Two sets of speakers can be connected and a socket for headphones is provided. Bass and treble controls give a useful kind of response shaping centred on about 900Hz and a defeat switch is included for purists or to enable ready comparison of a chosen setting with the 'straight line' reference. Very properly, an output muting relay gives the amplifier several seconds to settle on power-up before the speakers are connected.

Input selection is managed via a row or six push-buttons, with a seventh to select between the MM and MC input circuitry. A further six buttons operate the record-out options, this arrangement offering the maximum flexibility, as is becoming increasingly popular, to enable the user to listen to one source whilst recording from another. The large (5 cm) volume control knob is calibrated in Decibels and is of the continuous rotation type, not stepped. A balance control is fitted and has a centre indent. Speaker outputs are via substantial binding posts of the type which take bare wire ends and all the other signal socketry is via phono sockets. A ground screw for the turntable earth is provided. The AV/aux input sockets are duplicated on the front panel with an adjacent switch to select between front and rear. This allows the temporary connection of an ancillary item without the need for a sortie amongst the spaghetti of cables which will have been installed at the back of the amplifier.

The valve complement is in fact just two triodes and having gone to the trouble of incorporating them Lux have decided to put them on show through a small Perspex window on the fascia so that listening is enhanced by the warm glow of the filaments. To the left of this window is a "pre-heating" switch which, when selected, keeps a proportion of the valve's heater voltage flowing while the amplifier itself is switched off (provided of course that it is left plugged into the mains); this overcomes the warm-up time usually associated with valve equipment and also prevents what the booklet terms rush current. The valves are significantly 'under run' and are expected to last almost indefinitely. Input selection, MM/MC, tone control selection and pre-heating 'on' are shown by illuminated legends.

Internally the amplifier is well laid out using several circuit boards. The veritable nest of wiring looms is not uncommon in Japanese hi-fi components, but again these are well arranged and grouped. Two mains transformers are employed, one for the solid-state devices and the other to power the valves. High quality components are used throughout; indeed the whole unit has a quality feel to it. The UK models come fitted with a captive two-core mains lead, which is no doubt safe enough although some innocuous 'leakage' current can be felt on the cabinet as a result. I would suggest running an earth lead up to the ground screw in any event as this cures the effect and the amplifier can then become the earth reference for the entire system. Performance

"Feel every piece of the aftertastes of glittering sound by whole of your body, and your listening pleasure is further enhanced" the presentation brochure suggests, which is taking hi-fi a bit far in my view, but no doubt something was lost in the Japanese-to- English translation. I used this amplifier as the centre-piece of two separate set-ups, one using Quad ESL-63 loudspeakers and the other Mordaunt-Short MS300s. Headphones were also employed, albeit briefly. My Linn/Rega turntable/ pickup arm combination was fitted alternately with a Grace F9-E moving-magnet cartridge and the new Ortofon MC20 Super Me. Compact Disc, FM radio and high quality cassette tape sources were also employed.

With the various permutations these items allow the impression gained was one of the generally euphonious nature of the sound; there is an almost velvety quality to this amplifier which is extremely pleasant on the ear. Only the MC input affected this to any negative degree, introducing a very slightly coarse edge in comparison with MM. While one has to be extremely careful in such comparisons-since it is quite possible for two outwardly identical cartridges to sound different let alone two using different operational modes - I was left with the feeling that the amplifier produced a more grateful and transparent sound via MM.

There is excellent stability to the stereo soundstage projected and this remains unaffected by even the most dynamically energetic and demanding musical material. (With less good amplifiers the image is often pulled about under such conditions.) To me this suggests that the power supply is both very capable and well matched to the circuitry it feeds. As usual the CD input is the same sensitivity as the other line-level inputs so some adjustment of the volume control when switching from source to source is required to achieve the same kind of overall level. The facilities incorporated are sensible (for once here is a Japanese amplifier that goes without the ubiquitous 'loudness' control) and well tailored.

Idiosyncratic it certainly is, but the Luxman LV-103 offers very good sound and a high standard of build quality and finish. It seems largely indifferent to various speaker loadings and so is unlikely to suffer any compatibility problems. Moving-coil devotees might like to investigate the possibility of using a separate head amplifier and feeding this into the MM input. £395 may seem expensive but what it gives you will not disappoint and I can think of no other integrated amplifier at the price which would cause it any significant embarrassment.