NAD C420 Inside The Nad C, PARASOUND TDQ-150, audioXpress June, PHOTO 3 Interior view of NAD C

steps of 50kHz. The AM tuning steps are 10kHz (9kHz for the 230V version).

The RDS PS (Program Service) automatically displays the name of the radio station you are listening to. The RDS RT (Radio Text) button displays any additional informa- tion broadcast by the radio sta- tion, such as program format, song titles, and so on.

You can operate the C 420 with one of NAD’s system remote con- trols via the front panel IR sensor, or through the rear panel NAD- Link jacks. You can also switch tuner AC power from amps, pre- amps, and AV processors that use the 12V-trigger system.

unit is very light and easy to move. The front panel has six push buttons: On-Off, FM-AM, Preset Up/Down, and Tune Up/Down. The yellow backlit LCD display shows band and frequency, the se- lected station preset, and a

stereo/mono indicator.

The rear panel (not shown) has an IEC power receptacle with inte- gral fuse holder, external IR con- trol port, +12V trigger jack, audio output jacks with gold-plated shells and tin center contacts, a two-conductor AM antenna con- nector, and a threaded 75Ω F-type FM antenna jack. The third pin of the AC receptacle is not connected to the chassis.

The ten-page manual is entirely in English. Ancillary equipment includes the remote control with batteries, power cord, FM dipole antenna, 300Ω-to-75Ω balun, and AM loop antenna with self-adhe- sive bracket.

INSIDE THE NAD C 420

Photo 3 shows the NAD C 420 with the cover removed. The power transformer occupies the left rear

of the chassis, and connects to the switch/LED board in the left front. The display/control PC board sits behind the front panel. Occupying most of the right side of the chas- sis is the large single-sided pheno- lic tuner board. A schematic was not furnished with the unit.

The display board connects to the tuner board through three rib- bon cables, and the power trans- former secondary connects via

Eight pages of the 43-page man- ual are devoted to instructions in English. Other languages are French, German, Spanish, Italian, Portuguese, and Swedish. Pro- gramming isn’t all that intuitive, so there is a two-page section on storing, recalling, and labeling presets. Ancillary items include an AM loop antenna, the usual FM di- pole antenna, and a set of generic RCA audio interconnects.

PARASOUND TDQ-150

The TDQ-150 (Photo 2) is half the width, height, and depth of most conventional audio components. It is designed for main or remote- zone use in a custom sound system installation where space is at a premium. The unit sits on four plastic feet with foam-rubber in- serts. Holes are provided on the front plate for rack mounting. The

The TDQ-150 comes with a full- function remote control with sep- arate on and off codes, “Zpre” Zone Preamplifier control, and AC line and DC triggering capabilities. To store memory presets you must use the remote. While the opera- tion is a bit more intuitive than the NAD C 420, I still prefer the car radio method: tune the station, press the preset button for 5 sec- onds, voilà, you’re done!

You can assign up to 30 presets to any AM or FM stations. The CMOS memory retains preset sta- tions by means of a super-capaci- tor for up to 30 days without AC power. RDS program service data or text is not displayed.

FM mono is automatically en- gaged below 15µV RF signal level. The tuning increments for FM are the odd 200kHz U.S. spacings. The AM tuning steps are 10kHz.

PHOTO 3: Interior view of NAD C 420.

A-2091-1

FIGURE 1: Frequency response—FM tuners.

TABLE 1

NAD C 420 SPECIFICATIONS AND MEASURED RESULTS

FM SECTION SPECIFICATIONS	NAD C 420	MEASURED RESULTS
Usable sensitivity, mono	2.2∝V, IHF	22dBf, 3.4∝V (75Ω)
Usable sensitivity, stereo	16∝V, IHF	36dBf, 17∝V (75Ω)
Mono quieting @ 50dB	23.3dBf, 4.0∝V	25dBf, 5∝V (75Ω)
Stereo muting/blend	(75Ω)	37dBf
Stereo quieting @ 50dB	40.2dBf, 28∝V	38dBf, 22∝V (75Ω)
S/N, A-wtd, 65dBf, mono	(75Ω)	71dB
S/N, A-wtd, 65dBf, stereo		69dB
Frequency response	30−15kHz, ±1.5dB	20−15kHz, +1.2, −0.5dB
THD, 1kHz mono	0.20%	0.087%
THD, 1kHz stereo	0.30%	0.29%
THD, 100–10kHz, mono	>45dB	0.22%
Separation, 1kHz		54dB
Capture ratio, 45dBf	2.4dB
Image rejection, 400kHz	>60dB
Auto search threshold		27dBf
Output impedance		420Ω, 1kHz
Output level		550mV, 1kHz

A-2091-2

FIGURE 2: FM quieting—NAD C 420.

A-2091-3

FIGURE 3: FM quieting—Parasound TDQ-150.

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