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.
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
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 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.
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
FIGURE 1: Frequency response—FM tuners.
FIGURE 2: FM quieting—NAD C 420.
FIGURE 3: FM quieting—Parasound TDQ-150.
TABLE 1
NAD C 420 SPECIFICATIONS AND MEASURED RESULTS
FM SECTION SPECIFICATIONS NAD C 420 MEASURED RESULTS
Usable sensitivity, mono 2.2
µ
V, IHF 22dBf, 3.4
µ
V (75
Ω
)
Usable sensitivity, stereo 16
µ
V, IHF 36dBf, 17
µ
V (75
Ω
)
Mono quieting @ 50dB 23.3dBf, 4.0
µ
V 25dBf, 5
µ
V (75
Ω
)
(75
Ω
)
Stereo muting/blend 37dBf
Stereo quieting @ 50dB 40.2dBf, 28
µ
V 38dBf, 22
µ
V (75
Ω
)
(75
Ω
)
S/N, A-wtd, 65dBf, mono 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 0.22%
Separation, 1kHz
>
45dB 54dB
Capture ratio, 45dBf 2.4dB
Image rejection, 400kHz
>
60dB
Auto search threshold 27dBf
Output impedance 420
Ω
, 1kHz
Output level 550mV, 1kHz
PHOTO 3: Interior view of NAD C 420.
A-2091-2
A-2091-3
A-2091-1
audioXpress June 2002 61
