Luxman R-117 Stereo Receiver
I was beginning to think there was something wrong with my FM stereo generator-until I measured the FM performance of this top-of-the-line Luxman AM/FM receiver. It not only restored my faith in my lab equipment, but renewed my belief in the ability of some companies to produce all-in-one receivers that equal some of the finest separate tuners and amplifiers I have ever measured or listened to.
I have been following Luxman's somewhat erratic history from the time they first introduced a few amplifiers, tuners, and receivers in the early 1970s. The then-independent company was often referred to as "the McIntosh of Japan." Indeed, Japanese audiophiles that I've met recently still think of Luxman in those terms. When the relatively small company became a division of the much larger Alpine Electronics in the early 1980s, some of the products introduced by the new management were not up to the standards of the original Lux Corporation. The new division seemed to be groping for a place in the highly competitive audio electronics field without having a clear design philosophy. Happily, the "new" Luxman management has brought the company back on track. They have allowed its dedicated and innovative engineers (many of whom have been with Luxman for a decade or more) to do what they do best: Design and produce superlative audio components that sound as good as they measure on the lab bench.
Among the special features of the R-117 is the ability to route signals from a CD player directly to the input of the power amplifier section, bypassing the input selector, record-out selector, dubbing switches, signal processor, subsonic filter, and balance control.
The power amplifier section uses a differentially connected, dual FET input stage and push-pull driver and output stages. It uses power transistors as drivers and has dual paralleled output transistors. The high dynamic headroom of the amplifier section is achieved through the use of signal-controlled Darlington switches that increase output-stage voltages by two-thirds for 30-mS intervals when output power reaches 175 watts per channel. The high-current emitter resistors for the output devices are monolithic, not wire-wound, to eliminate any possible inductive distortion components. A triple-shielded power transformer and fast-recovery diode rectifiers help to maintain steady supply voltages under widely varying load conditions. Speaker selection and protection relays are rated for 60-ampere peak currents.
The FM tuner section employs dual-gate MOS-FET devices for pre-selector r.f. and mixer stages, and uses five-gang varactor tuning. Separate buffer transistors for the PLL and mixer outputs are used for increased oscillator stability. There are three wide-band ceramic filters in the i.f. section, and an additional amplifier stage and ceramic filter are inserted in the signal path when the narrow-band mode is employed for increased selectivity. Quadrature FM detection is used for audio recovery, and a PLL multiplex decoder is used for stereo. An automatic high-blend circuit reduces noise during weak-signal reception, though at some sacrifice in stereo separation.
The infrared remote control supplied with this receiver will also control other Luxman components, such as a CD player, cassette deck, or turntable, and will work with Luxman's multi-room remote systems as well. Two sets of preamp-out jacks and one set of main-amp input jacks allow connection of additional amplifiers or other audio equipment at a point beyond the receiver's tone controls and signal processors. Extra signal-processing input and output jacks are provided in addition to the two sets of tape monitor loops.
A total of 20 station frequencies can be memorized by the tuner circuitry. A switch inside the receiver allows you to tune in 25- or 50-kHz increments, if you wish, to avoid interference when receiving those cable FM transmissions that shift frequencies away from the standard 200-kFlz multiples. Video signal sources can be connected to the receiver, and a video output terminal permits connection of a TV monitor. Wide-band video buffer amplifiers handle these video signals.
Control Layout
At the left edge of the R-117's all-black front panel are a power switch and a stereo phone jack. A display area near the power switch indicates tuned-to frequency, station preset number, stereo reception, signal strength, tuning mode, and "memory mode" when storing a preset station frequency. A multipath interference indicator, also found here, lights when the appropriate button is pressed-if and when multi-path interference is present.
Ten numbered buttons below the display are used in tandem with an additional "shift" button to store the 20 preset stations. Nine buttons to the right of the display select desired program sources (FM, AM, tape 1 or 2, phono, CD, videodisc, and video 1 or video 2). If the "CD Straight" button (also located in this area) is pressed, the CD input is connected directly to the power amplifier section, and no other program sources can be selected. Four buttons below the program selectors and their associated indicator lights are used to choose among four possible program sources for record-output assignment: Tuner, phono, CD, and videodisc. Two additional buttons in the same row control video 2-to-1 and tape 2-to-1 dubbing.
Two speaker selector buttons are in the lower left corner of the front panel. Nearby are an "FM Muting" button, the "Multipath" button mentioned above, a two-position i.f. bandwidth selector, an "Auto Seek" button for selecting the automatic signal-seeking tuning mode, a "Memory Scan" button that lets you listen to each preset station for 5 S, the "shift" button previously mentioned, the preset "Store" button, and small rotary bass and treble control knobs. Farther to the right, along the bottom section of the panel, are a "Tone Defeat" button, a subsonic filter button, a three-position loudness compensation switch ("Off" plus two levels of compensation), a balance control, and an MM/MC phono cartridge selector. A massive volume control with an inset illuminated indicator is at the upper right corner of this feature-laden front panel.
As you might expect, the rear panel is crammed full of jacks and terminals. The FM antenna terminal is a 75-ohm coaxial type, but Luxman provides a 300-to-75-ohm matching transformer in case you prefer to use a flat-ribbon transmission line. An AM loopstick is packed separately and snaps into place in a rear-panel clamp. There are 38 audio and video input and output jacks, twin sets of speaker output terminals, six convenience a.c. receptacles, and a chassis ground terminal. Also provided are DIN connectors for a unified remote-control system (if you use the R-117 with other Luxman components) and for an external remote sensor. A signal processor on/off switch opens the signal path so that an external device, such as a graphic equalizer, can be connected to the separate signal processor jacks.
Use and Listening Tests
I spent much of my auditioning time with this receiver listening to FM broadcasts. In my area, the FM dial is fairly densely populated, but rarely am I able to receive more than 45 or so signals with sufficient quieting to justify listening to them. In the case of the Luxman R-117, the satisfactory station count rose to 51! (I would hasten to add that in these FM listening tests, I use a rotatable multi-element outdoor antenna.) Despite the fact that I was able to listen in the wide i.f. mode during most of my tests, I found that I was able to use the narrow setting without sacrificing much separation and without noticing any audible increase in distortion.
Most of the remainder of my listening experiments were conducted using recently acquired CDs, including a couple of Delos releases featuring Flaydn symphonies and concertos (D/CD 3061 and 3062). Thanks to the Luxman's excellent electronics and to Delos' superb recording techniques, the sounds of cello and piano were truly magnificent, with dynamics and transient response that were almost indistinguishable, at times, from those of a live performance. For "bigger" sound, I played the two-disc Verdi Requiem recently released by Telarc (CD-80152). The clarity of the solo vocalists and the chorus, and the ease with which I was able to focus on specific voices against the full force of the Atlanta Symphony Orchestra, attest to the absence of dynamic distortion, which is not easily measured on the test bench.
All in all, Luxman has come up with an all-in-one receiver which, in terms of quality, is reminiscent of the separate amplifiers and preamplifiers for which the company earned its initial high marks.
