Denon TU-600 Tuner Review

Denon has applied the philosophy of “the simplest is the best” in the design of its new TU-600 AM/FM tuner. This approach is immediately apparent from the front panel, where most of the controls (all pushbuttons) form a single row for preset station and band selection. The ten preset buttons can be switched to store and recall a second group of ten station frequencies, giving the TU-600 a total of twenty memories. Each memory can be assigned to either an AM or an FM station, and pressing a button switches the tuner to the appropriate band as well as the specific station frequency. Small lights above the buttons identify the selected preset.

Like most current tuners, the TU-600 has digital-synthesis tuning, with the station frequency and band visible in a display window. Next to the frequency readout, a group of led’s indicate stereo reception, IF bandwidth, relative signal strength (in ten segments), and the status of the auto-tuning mode. In its automatic mode, the tuner mutes the output and searches for the next receivable signal up or down, depending on which of the tuning buttons is pressed, switching automatically between mono and stereo. Disabling the auto tuning switches the tuner to mono reception, disables the muting circuit, and changes the frequency by a single increment (200 kHz for FM, and 10 kHz for am) for each touch on the tuning button. Holding a tuning button in produces a rapid scan in the selected direction. Wide or narrow if bandwidth is also selected by a button on the front panel.

In spite of the TU-600’s compact size, simple appearance, and modest price, its specifications suggest that it is far from being a “basic” tuner. Although all its specs are good or better, those for harmonic distortion (0.03 and 0.04 percent for mono and stereo, respectively) and signal-to-noise ratio (92 and 86 dB for mono and stereo) are quite literally “state of the art,” simply unheard of in a tuner at the TU-600’s $350 list price.

The Denon TU-600 measures 18-1/4 inches wide (including the plastic-covered wood-grain end plates), 11 inches deep, and only 2-3/4 inches high. It weighs just over 8 pounds.

Lab Tests

We repeated most measurements of the TU-600 using both the narrow and wide IF bandwidths. With the wide bandwidth, the altemate-channel selectivity was an acceptable 43 dB, and the adjacent-channel selectivity was 3 dB. Switching to the narrow bandwidth changed these measurements to 76 and 5.5 dB, respectively. The chief performance difference between these two settings was the tuner’s stereo distortion, which was 0.5 to 1.5 percent over a wide range of signal strengths with the narrow bandwidth. Although this level of distortion is not likely to be audible on most program material—it is comparable to the distortion of the FM tuner section of a good automobile radio— the distortion was so much less in the wide-bandwidth mode that we would strongly urge using that mode at all times unless a specific interference problem is encountered. Like a few other tuners, this one requires a strong signal for its best performance, but at 85 dBf (10,000 microvolts, or μV) the mono distortion was just under 0.02 percent, the lowest figure we have ever measured from an FM tuner. Even in stereo, the wide-bandwidth distortion was an impressive 0.046 percent.

The TU-600 also rivaled the best tuners we have tested in its noise quieting. At 85 dBf it measured 92 dB in mono and 86 dB in stereo, essentially as rated, and it was not affected by the choice of IF bandwidth. The sensitivity measurements were not particularly notable, though more than adequate for any but the most extreme fringe-area installations. The am rejection was excellent, the capture ratio good. The 19-kHz pilot-carrier leakage was a very low —80 dB, and hum was nearly unmeasurable at —90 dB. The FM frequency response was flat from 30 to 10,000 Hz and down 1.3 dB at 15,000 Hz. Channel separation (wide-band) was a maximum of 56 dB at 2,000 Hz, narrowing to 28 dB at 30 Hz and 32.5 dB at 15.000 Hz. The narrow-band mode reduced the separation to a nearly uniform 24 to 27 dB between 30 and 9.000 Hz, improving to about 35 dB at 15,000 Hz. In sharp contrast to the exceptional FM performance, but like virtually every other tuner we have tested, the am section’s frequency response was poor. The Denon TU-600 produced one of the most restricted AM response curves we have ever seen, down 6 dB at 45 and 1,700 Hz from its maximum at 400 Hz.

Comments

The unassuming Denon TU-600 is one of the finest FM tuners we have had the pleasure of using. Before the availability of our Panasonic signal generator, we would have been unable to measure its noise level and distortion. Although the usable sensitivity was not noteworthy, most of its other measurements were. Even at the 65-dBf signal level used for most tuner ratings, its noise and distortion readings were outstandingly low, and for those listeners able to supply it with an 85-dBf signal, this tuner should handily surpass the performance qualities of almost any FM broadcast station. From a practical (audible) standpoint, it even approaches the noise and distortion levels of a compact disc.

This is the sort of performance one might expect (but almost never gets) from a “supertuner” selling at a premium price. In its moderate price range, the Denon TU-600 stands alone, providing convincing proof that the simplest can indeed be the best.

Read all

Denon reviews

Read all