A Fisher "Digital" Receiver
Fisher RS-250 AM/FM receiver, in metal case. Dimensions: 17 1/4 by 5 1/4 inches (front panel), 14 inches deep plus clearance for controls and connections.
AC convenience outlets: one switched (60 watts max.), one unswitched (120 watts max.).
Price: $430. Warranty: "limited," two years parts and labor.
Manufacturer: made in Japan for Fisher Corp., 21314 Lassen St., Chatsworth, Calif. 91311.
A newcomer to componentry, viewing this receiver without predisposition or prejudice, might find it capable, sensibly designed, and not particularly distinctive in any material respect: very much in the mainstream of today's receivers, in fact. We begin with this statement because more experienced eyes-including some on our staff-look for some trace of the "old" Fisher whenever they hear the name. They won't find any here, nor should they expect to; to judge the products of Fisher Corporation by the standards of Fisher Radio (and therefore of its founder and president, Avery Fisher) is unfair to both. Circuits, markets, production economics, and life styles have changed, and the Fisher name along with them. At the same time, the RS-250 vividly documents Fisher's liveliness, it has not been consigned to that mid-fi graveyard in which lie so many once-great audio names.
Take, for example, the digital frequency display. In Fisher Radio's last days there were a few ultra-expensive "digital tuners"; today's micro-technology puts them only a chip away and-together with the RS-250's LED signal-strength display-makes them too cost-effective to be ignored in a competitive market. The Fisher design includes only these two elements plus pilots for stereo reception and servo lock on the station: There is no analog tuning scale or multipath indicator or channel-center display. This last would make no sense in any event, because the servo keeps the station centered and cannot be defeated for manual second-guessing. As a result, tuning "clings" to any station it is locked to; if you turn the tuning knob (and hence the main tuning capacitors) with a gentle enough hand, the servo will follow you, compensating for the basic mis-tuning, for 0.5 megahertz or more--that is, better than two channels away. Throughout the process, the digital display, as well as the sound, will confirm that the station remains locked in, despite the movement of the tuning knob. And, predictably with such a design, the actual FM performance is very good indeed.
The design is otherwise quite straightforward. There is provision for two tape decks (and Tape 1 can avail itself of either standard pin jacks or a DIN socket) but without dubbing switching; you must reconnect one deck to copy tapes. The tone controls do not influence response at all at their detented center positions. At other settings, they shelve toward the frequency extremes, with maximum actions of about +15 to-12 dB. The infrasonic filter is quite efficient; the high filter has a gentle slope and relatively low hinge frequency, dulling musical sparkle along with any hiss. The loudness action provides some compensation in the extreme highs as well as a broad bass boost relative to 1-kHz response. The volume control detents deliver increments of about 1-2 dB over most of the control range, only exceeding 3 dB at more than 50 dB of attenuation, and thus are more consistent and fine-grained than might be expected in this price range.
The measurements from Diversified Science Laboratories demonstrate a consistent excellence of technical performance, in fact. The dynamic headroom is unusually generous and means that, with 8-ohm loads, the amplifier will handle music transients to the equivalent of 85 watts per channel. Distortion not only is Fisher RS-250 amplifier section
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Fisher RS-250 tuner section
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RATED POWER
17 08W 150 watts(/channel
OUTPUT AT CLIPPING
8-ohm load 4-ohm load 16-ohm load
181 08W 167 watts(/channel 19 dBW (79 watts)/channel 161 08W 145 watts)/channel
DYNAMIC HEADROOM (8 ohms)
FREQUENCY RESPONSE
+0,-108, < 10 Hz to 20.8 kHz;
-3 dB at 66.4 kHz
RIAA EQUALIZATION x %d8, 20 Hz to 20 kHz;
-2% dB at 5 Hz 21/4 dB
INPUT CHARACTERISTICS
Ire 0 dBW; A-weighting)
sensitivity S/N ratio
HARMONIC DISTORTION
1THD; 20 Hz to 20 kHz)
at 17 dBW 150 watts)
<0.017% at 0 dBW (1 watt)
<0.01% aux fixed-coil phono moving-coil phono 19.5 mV
0.36 mV 9.1 IN 82dB 77dB 801 d8
PHONO OVERLOAD (1-kHz clipping)
fixed cod 260 mV moving coil 5.8 mV
PRONO IMPEDANCE fixed coil moving coil 51k ohms; 100 pF 20 ohms
DAMPING FACTOR (at 50 Hz) 80
HIGH FILTER-3 dB at 2.9 kHz, 6 dB/octave
INFRASONIC FILTER-3 dB at 15 Hz: 12 dB/octave
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very low, but consists of no significant harmonics beyond the relatively benign second. Though the resistive loading from fixed-coil phono pickups is a hair above the normally specified 47,000 ohms, the difference is not large and the "classic" nature of the loading-with clear-cut capacitive and resistive values-helps prevent unpleasant surprises even with a "fussy" cartridge.
Unfortunately, for both Fisher and its competitors, even a receiver this good is not really out of the ordinary these days. That is, we can cite no pre-emptive reason either for buying or for not buying the RS-250. There are minor differences, to be sure; but the plateau on which receiver design finds itself is both elevated and relatively featureless. If the latter characterization sounds boring, just remind yourself that you're the beneficiary of the former.
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[Preparation supervised by Robert Long, Peter Dobbin, and Edward J. Foster. Laboratory data (unless otherwise noted) supplied by CBS Technology Center or Diversified Science Laboratories.]
(High Fidelity, May 1981)
Also see:
Audio-Technica AT-155LC phono pickup