A Supertuner for a Medium Price
Phase Linear Model 5100 Series II tuner
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MONO FM FREQUENCY RESPONSE
5.00.m 001 HZ 20 DB
0-5 50 100 200 500 1K 2K 5K 10K
+1/4,-11/4 dB, 20 Hz to 15 kHz
STEREO FM FREQUENCY RESPONSE
20K 51 W 5ene,1111 HZ 20 DB 10 20
-30
-40 50
-60 50 100 200 500 1K 2K 5K 10K
+44,-11/4 dB, 20 Hz to 15 kHz
CHANNEL SEPARATION dB, 60 Hz to 9.5 kHz
>40 dB, 20 Hz to 15 kHz
FM SENSITIVITY & QUIETING 20K
5100 131 DBF 0 10 20 30 40 50 60 stereo noise (quieting)
----- mono noise (quieting)
Stereo sensitivity (for 50-dB noise suppression) 36 dBf at 98 MHz, with 0.34% THD+N 1371/4 dBf at 90 MHz; 36 1/4 dBf at 106 MHz)
Mono sensitivity (for 50-dB noise suppression) 12 1/4 dBf at 98 MHz
Muting threshold 27 dBf
Stereo threshold 27 dBf
Stereo S/N ratio (at 65 dBf) 69% dB
Mono S/N ratio fat 65 dElf) 7444 dB 70 80 90 CAPTURE RATIO 1 dB ALTERNATE-CHANNEL SELECTIVITY 48 1/4 dB 100 411M AC POWER REC. LEVEL CHECK ( ON/OFF) FM MUTING ION/OFF) & MODE (AUTO/MONO) FUNCTION (FM/AM) TUNING MODE (AUTO/MANUAL) MEMORY SELECTORS MEMORY TUNE UP TUNE DOWN
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Phase Linear Model 5100 Series II stereo FM/AM tuner, in metal case.
Dimensions: 19 by 3 1/2 inches (front panel), 12 inches deep plus clearance for "handles" and connections. Price: $449.95; optional SPO (oak) or SPW (walnut) side panels, $49.95.
Warranty: "limited," three years parts and labor. Manufacturer: made in Japan for Phase Linear Corp., 20121 48th Ave. W., Lynnwood, Wash. 98036.
Precision is the raison d'etre of digitally synthesized tuning. Although such designs made an appearance some years ago, early models had the golden touch: They were more suited to Midas' pocketbook than Everyman's. With the advent of large-scale integrated circuits, this tuning precision has become available to somewhat less affluent audiophiles. One tuner that has taken advantage of these economies is Phase Linear's 5100 Series II, which leapfrogs its forebears by affording digitally synthesized AM as well as FM and a more convenient means of providing station presets.
In the 5100, the allowable FM reception frequencies lie at 100-kHz intervals. Since current U.S. practice requires FM stations to be precisely 200 kHz apart, all possibilities are covered. In the AM band, stations are 10 kHz apart, and the tuner aligns in like manner. There is discussion within the FCC of crowding more AM stations onto the band by tightening the spacing to 9 kHz; should this happen, the 5100 will accommodate the change via a back-panel switch. (Another back-panel switch chooses between standard 75-microsecond FM de-emphasis and the 25-microsecond standard for Dolby broadcasts.) The FCC also has discussed tightening the FM spacing to 150 kHz. This change (which HF strongly opposes, and which seems less likely to come about at this writing) could not be accommodated by this or most other digitally synthesized tuners on the market. So, while the synthesis approach implies virtually perfect tuning, it also entails some gamble that its discrete frequencies will remain those of the broadcast channels.
The 5100 will scan the band automatically, stopping at each relatively strong station--above 40 dBf or so. To get it to move on, you merely press one of the tuning switches (uP or DOWN). At the end of the band, the scan direction reverses automatically. If you put the tuning-mode switch in MANUAL and touch one of these tuning switches, the tuner shifts one increment (100 kHz) for each touch; if you hold the switch down, it steps increment by increment in the appropriate direction. The received frequency appears on the digital readout, which, being unambiguous, requires no channel-center indicator. A five-light signal-strength indicator replaces the traditional meter and covers a range from 19 dBf (first light) to 59 dBf (the threshold of the fifth). Six favorite stations (in both AM and FM) can be preset with a technique that seems to us simpler, more logical, and more foolproof than average for such a feature: You tune the station, press MEMORY, and (within three seconds) press one of the six station-selector buttons. Only during the three-second period can an old memorization be destroyed or replaced; even a power failure will leave the presets intact. And, as with a conventional tuner or receiver, the 5100 comes on at the frequency to which it was tuned when it was switched off.
Diversified Science Laboratories' data show the 5100 to be among the most sensitive tuners to have ever crossed its bench: A mere 12 3/4 dBf of input in mono or 36 dBf in stereo produces 50 dB of noise suppression at midband, and the sensitivity is reasonably uniform throughout the band. The muting and stereo thresholds are identical, typical of tuners that combine the muting and mono in one switch, as this one does. (The mute is defeated in mono and always active in the auto stereo/mono mode.) A reasonable amount of hysteresis has been built into the threshold to minimize annoying switchovers during fading, and the threshold is relatively high-equivalent to about 65 dB of quieting in mono, 42 dB in stereo.
The ultimate signal-to-noise ratios are very good in both modes, as are the figures for distortion (especially in stereo), pilot cancellation, AM suppression, and capture ratio (suggesting good ability to handle multipath-contaminated signals). Frequency response is exceptionally uniform, even beyond the 15-kHz maximum of broadcast audio, and the stereo separation is essentially total. A REC LEVEL CHECK replaces the audio with a 370-Hz tone that corresponds to approximately 55% modulation, close to the 50% Dolby-calibration level.
There is one weak point among the superlatives. Especially in view of the 5100's exceptional sensitivity, which tempts us to receive distant weak stations at frequencies close to those of strong local ones, the alternate-channel selectivity seems less than optimum. Under such conditions, the stronger (alternate-channel) station can break through when it is modulated heavily. Of less importance is the fact that the 5100's auto-scan mode occasionally will stop at the sidebands 100 kHz above or below a very strong station. (One tap on the appropriate tuning switch sets the matter right.) And we consider the panel markings very difficult to read.
But this Phase Linear is a pleasure to use. It is extraordinarily sensitive and produces wonderfully clean sound on the majority of stations, perhaps because of its multipath-rejection ability. There's no need to worry about how well it is tuned: You can't make a mistake. The foolproof convenience of the presets extends to the AM band as well as the FM-an exceptional feature in a high-performance tuner. And (perhaps best of all in today's economy) it costs about half the price of the super-tuners in which digital synthesis first claimed audiophiles' attention.
HARMONIC DISTORTION
[THD+N] stereo mono at 100 Hz 0.22% 0.19% at 1 kHz 0.097% 0.13% at 6 kHz 0.13% 0.27%
STEREO PILOT INTERMODULATION 0.13%
IM DISTORTION (mono) 0.061%
AM SUPPRESSION 60'/.dB PILOT (19 kHz) SUPPRESSION 80 dB SUBCARRIER (38 kHz) SUPPRESSION 83 dB
(High Fidelity, Jan. 1980)
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