NAD C420 User Manual

NAD C 420 stereo AM/FM tuner.
NAD Electronics International, 633
Granite Court, Pickering, Ontario,
Canada L1W 3K1, [phone],
www.NADelectronics.com. $249
U.S. Dimensions: 435mm W

×

70mm H ×285mm D. Net weight:

8.8 lbs (4kg). Warranty: two years
parts and labor.

Parasound TDQ-150 stereo tuner.
Parasound Products, Inc., 950
Battery St., San Francisco,
CA 94111, [phone],
www.parasound.com. $269 U.S.
Dimensions: 9.5” W

×

1.75” H

×

7” D. Net weight: 4 lbs. Ten-year
limited warranty.

The NAD C 420 and Parasound TDQ­150 AM/FM stereo tuners repre-

sent the budget end for high-end
tuners. These two manufacturers’
higher-priced tuners (NAD C 440,
$349; and the full-size Parasound
TDQ-1600, $400) offer better FM
sensitivity and lower audio distor­tion specifications. However, if
you don’t require fringe area re­ception, these two tuners repre­sent excellent values.

NAD C 420

Photo 1

shows the C 420 front
panel. Just above the power switch
on the left is a small green LED in­dicator, which turns amber in
Standby mode. A row of six push
buttons selects Blend, Memory, FM
Mute/Mono, AM/FM, Display
modes, and Preset/Tune functions.
The white fluorescent display

screen shows the band and fre­quency of the station being tuned,
FM stereo, whether the station is a
memory preset, and whether Blend
and FM Mute are engaged. It also
has a vertical seven-bar-graph sig­nal strength indicator.

Pressing the display button cy­cles the display to RDS program
service. Another push cycles it to
RDS text. The display then returns
to the default mode after a few
seconds. The infrared sensor is lo­cated on the left side of the dis­play window. A rocker switch on
the right side of the unit is for the
Preset/Tune functions.

The tuner chassis is black paint­ed steel, and the cover is held on
with five screws. The front bezel is
plastic and the unit sits on four

plastic feet with elastomer
rings on the bottom. There is
adequate finger space under
the unit to easily lift it.

The rear panel (not shown)

has the attached two-prong
polarized AC line cord, a +12V
trigger jack, the “NAD-Link”
input and output jacks,
stereo audio jacks with gold­plated shells and tin center
contacts, a two-conductor AM

antenna connector, and a threaded
75Ω F-type FM antenna jack.

The C 420 provides up to 30 sta­tion presets, which you can use in
any combination of AM and FM
stations. FM Mute and FM Blend
status information is stored with
each FM preset. Empty presets are
skipped over during tuning to pro­vide quicker access to the stored
stations.

The preset information is stored
in non-volatile EEPROM memory,
which provides permanent power­off storage. Many tuners use
“super capacitors” to hold the pre­set memory in CMOS chips for a
limited time—maybe a month or
so. My own NAD 4155 uses a now­tired super cap, and it must be
powered up at least once a week to
maintain all the presets.

FM Mute/Mode switches the C
420 to mono and disengages the
muting circuitry so you can manu­ally tune weak stations. FM Blend
provides a means to automatically
reduce noise and hiss on weak sta­tions while still retaining some
stereo separation. Once the signal
level drops below a certain thresh­old, it will revert to mono. The
tuning increments for FM are in

FM Tuners:
NAD and Parasound

Reviewed by Charles Hansen and Nancy and Duncan MacArthur

PHOTO 2: Front view of Parasound TDQ-150.

PHOTO 1:

The NAD C 420

stereo tuner.

60 audioXpress 6/02 www.audioXpress.com

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 informa­tion broadcast by the radio sta­tion, such as program format, song
titles, and so on.

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

Eight pages of the 43-page man­ual are devoted to instructions in
English. Other languages are
French, German, Spanish, Italian,
Portuguese, and Swedish. Pro­gramming 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 di­pole 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 remote­zone use in a custom sound system
installation where space is at a
premium. The unit sits on four
plastic feet with foam-rubber in­serts. 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 se­lected station preset, and a
stereo/mono indicator.

The rear panel (not shown) has
an IEC power receptacle with inte­gral fuse holder, external IR con­trol port, +12V trigger jack, audio
output jacks with gold-plated
shells and tin center contacts, a
two-conductor AM antenna con­nector, 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 full­function remote control with sep­arate 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 opera­tion 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 sec­onds, voilà, you’re done!

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

FM mono is automatically en­gaged 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-adhe­sive 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 chas­sis is the large single-sided pheno­lic tuner board. A schematic was
not furnished with the unit.

The display board connects to
the tuner board through three rib­bon cables, and the power trans­former 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 2.2µV, IHF 22dBf, 3.4µV (75Ω)
Usable sensitivity, stereo 16µV, IHF 36dBf, 17µV (75Ω)
Mono quieting @ 50dB 23.3dBf, 4.0µV 25dBf, 5µV (75Ω)

(75Ω)
Stereo muting/blend 37dBf
Stereo quieting @ 50dB 40.2dBf, 28µV 38dBf, 22µV (75Ω)

(75Ω)
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 420Ω, 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