Product Review -
Kit Number 1 - October, 1996
By John E. Johnson, Jr.
NAD Electronics |
633 Granite Court; Pickering, Ontario L1W 3K1 · Canada |
Phone 905-831-6555; Fax 905-837-6357 |
Weltronics Corporation, P.O. Box 80584 |
San Marino, California 91108 |
Phone 818-799-6396; Fax 818-799-6541 |
KEF Electronics of America, 89 Doug Brown Way |
Holliston, Massachusetts 01746 |
Phone 508-429-3600; Fax 508-429-3699 |
NAD 412 AM/FM Tuner; Input sensitivity 37
dBf; Capture ratio 1.6 dB; I.F. rejection 90 dB; THD 0.3%; S/N 74
dB; Output impedance 600 Ohms; Size 3 1/4"H x 17"W x
11"D; Weight 9 pounds; $299
NAD 613 Cassette Tape Deck; Frequency response 30 Hz - 18 kHz
plus or minus 3 dB; Wow and flutter 0.1% DIN wtd. peak, 0.07% JIS
wtd. rms; THD 1.0%; S/N 58 dB (Dolby NR off); Dolby B, C, HX Pro;
Size 5"H x 17"W x 11"D; Weight 11 pounds; $349
AMC-CD8 Compact Disc Player; DAC: 1 bit MASH, 18 bit resolution,
32 x oversampling; Analog filter 5 pole; Frequency response 5 Hz
- 20 kHz plus 0, minus 0.5dB; S/N 107 dB; Channel separation 90
dB; Output impedance 80 Ohms; Output level 2 Vrms; Remote
control; Outputs one pair analog RCA, one digital RCA; Size 3
1/4"H x 17"W x 11"d; Weight 9 pounds; $299
KEF Coda 8 Speakers; Two way ported; One 1" soft dome
tweeter, one 6 1/2" doped cone mid/bass driver; Frequency
response 45 Hz - 20 kHz plus or minus 3 dB; Crossover frequency
3.5 kHz; Sensitivity 91 dB/w/m; Power handling 10w - 100w per
channel; Size 13"H x 8"W x 11 1/2"D; Weight 6 1/2
pounds each; $300/pair - black vinyl finish
This is the first in our series of Kit Reviews, as per our
readers' requests. As often as we can, we will publish reviews of
complete "Turn key" systems at various price and
performance levels. Some will be audio-only, as this one is, and
others will be home theater. So, let's get on with it.
The present system could be defined as a mini, because of its
compact size in total (see
photo). It is not as mini as the
ones you see in the electronic supermarket chains, but oh what a
difference in the sound. The (essentially) one piece mini systems
one finds elsewhere for $300 - $700 have more features than one
can count (almost), but we think they sound a bit metallic, sort
of like a super boom box. The NAD/AMC/KEF package we put together
has separate power supplies for each of the components (toroidal
transformers), remote control for one of the components (CD
player), but not nearly as many features as the one piece minis.
The question is, what are you looking for in a mini? To me, sound
quality is utmost. To heck with features if they are at the
expense of the sound. So, we put together a "mini" that
sounds great at reasonable cost ($1500). If we added a larger amp
and speakers, one could classify this as a full sized system, so
"mini" is really semantics. The speaker size and
amplifier power, to us, make this an official mini.
The NAD 310 amplifier is probably the most shocking component in
this package in terms of what you get for the money. It is rated
at 20 watts rms/ch into 8 Ohms, but the power supply is designed
to deliver higher current, meaning that it will work with low
impedance loads. It has a toroidal transformer, is solidly built,
and supposed to be capable of delivering 20 amps peak (actual
current flow is determined by Ohm's law: Current =
Voltage/Resistance). There is a small, but noticeable turn-on
thump. Circuits that eliminate such thumps cost money, and NAD
has opted to keep the price way, way down. Each channel of the
output stage combines an N-MOSFET with a bipolar transistor . . .
very unusual. There are no triple emitter followers, which,
again, keeps the cost down. Local negative feedback around the
output transistors, together with output capacitors, keep the amp
stable and free of DC offset. Essentially the 310 is a dual mono
design. All the inputs are line-level (Video, Aux, Tuner, CD,
Tape Loop, and Portable CD). The Portable CD input, on the front,
allows you to connect your walkaround CD player (or portable tape
cassette player for that matter). Tone controls for treble and
bass can be defeated (bypassed), for those of you who are
purists. The KEF Coda 8s have received worldwide acclaim, and
they are 6 Ohm nominal. So, the 310 is just right for these
speakers. Indeed, we were able to get well over 90 dB with this
speaker and amplifier combination, with the sound being very
clean and not boomy. The KEFs have the woofer at the top and the
tweeter at the bottom. They know that these speakers will be on
shelves, and woofers close to other surfaces can result in bass
loading. They are also ported at the front, another feature that
is handy when they are probably going to end up very close to the
wall. We would also recommend using felt pads underneath the
speakers to reduce vibration transfer between the shelf and the
enclosures. The back of the speakers have binding posts, and we
recommend that you use higher grade (but entry level) cables for
this one connection, such as Nordost Flatline 2-Flat or their new
cable Octava. The RCA interconnects that come with the various
components are OK with this system (I never thought I would hear
myself say this). Save your high-end interconnect money for
component upgrades down the road.
The NAD 412 FM/AM tuner that we put with this kit is really nice.
Plain, and simple, but nice. None of the major FM stations that
we listen to had any extra sibilance, indicating that it is very
sensitive and locks right on. A "Blend" switch allows
tuning in to weaker stations, and reducing the stereo separation,
but not eliminating it. A "Mono" switch is used for the
really weak stations. The "Mode" button switches
between "Tune", "Preset", and
"Search". Tune allows manual tuning of stations down to
hundredths of a MHz (this is unusual), for example, 106.02. There
are 12 presets for FM and 12 for AM. A "Lock" button
fine tunes the station to the strongest region. The station
indicator is LCD, illuminated from behind, and easy to read in
the dark. The back panel has good connections for the antennae,
RCA jack outputs, and RCA input/output for linking with other NAD
components. (A new NAD product, the NAD 710, available in
December, 1996, will have the 310 and 412 combined into one
package, for $299.)
Even if you don't purchase pre-recorded cassette tapes, no system
would be complete without a cassette recorder/player, since we
all like to have copies of our favorite CD tracks to listen to in
the car. The NAD 613 Cassette Deck fills the bill here. The front
load open/close operation is very smooth, and all readouts,
including the tape counter, are electronic (rather than a
mechanical counter). The back panel has two RCA input and two RCA
output jacks, along with an in/out NAD link. Recording/playback
is calibrated in 2 dB steps from -10 dB through 0 dB, up to +8
dB. Dolby B and C Noise Reduction (NR) are included, along with
Dolby HX Pro. Dolby Noise Reduction (TM) works by increasing the
recording level of quiet high frequency portions of the signal.
Then during playback, the reverse occurs, reducing audible tape
hiss. Dolby B reduces noise by 10 dB and C by 20 dB. The newest
NR is Dolby S, which reduces noise in the lower frequency bands
as well, but S is not included on this deck. To use B or C NR,
the Dolby NR button on the front panel is pressed, selecting the
choice. The same NR scheme should be used for recording and
playback of any one tape (most likely B if the tape is for the
car). What I really like though, is the HX Pro. It uses a self
regulating bias which allows recording at higher levels than
would be possible otherwise. It is always in the circuit and
cannot be turned off, but there is no need to turn it off. We set
the recording level such that peaks occurred at +2 to +4 dB
rather than 0 dB, and it really works! With this setting, the
music bounces around -4 dB to 0 dB, with occasional peaks at +2
dB, and occasional lulls at - 10 dB. In a way, this reduces hiss
as well, because the playback level on the amplifier can be
turned down. Bias is a high frequency tone that is recorded onto
the tape along with the music (in the case of the 613, it is 107
kHz). Bias is necessary for tape recording to work. However, when
strong high frequencies are present in the music, they act as
bias in themselves, and along with the recorder's own bias, can
overbias the tape. The HX Pro circuit senses the amount of bias
and regulates it according to the high frequency content of the
music, thereby allowing higher recording levels to be set. There
is also a manual bias control, which allows the user to vary bias
according to personal preferences. With decreasing bias, the high
frequency response is extended, but the maximum recording level
is reduced accordingly. If you start from a typical bias point
and decrease bias, the high frequency sensitivity is increased,
and thus high frequency response is extended. The maximum
recording level will be reduced because the tape will become
underbiased, rather than because the bias is contributing to tape
saturation (overbiasing). Practically speaking, the increase in
distortion will limit the level that anyone would want to record
at. So, the amount of bias applied balances the frequency
response with recording level capability. "High Bias"
blank tapes are made of magnetic materials that will allow high
amounts of bias to be applied, yet still providing an extended
frequency response and high recording levels. Obviously, they are
the more expensive blank tapes. A "Play Trim" control
on the NAD 613 is used to adjust playback of tapes that are old
or otherwise improperly biased. This deck has a lot of features,
except for microphone inputs (most decks these days don't have
any), and is very easy to listen to (it has a headphone jack for
privacy). In fact, I liked it without any Dolby NR, and just set
the recording level a little higher than usual (with older decks,
the setting would have to be peaked at 0 dB, which is the
approximate maximum recording level without significant
distortion).
The system is rounded out with an AMC Weltronics CD-8 Compact
Disc Player. It has a front loading single CD transport
mechanism, with front panel function buttons for open/close,
play, pause, stop, program, repeat, time, track, and search. It
is very simple to operate, like the NAD components in this kit.
The remote control is also quite easy to use. This is one of the
reasons we included the CD-8 here (easy to use). It is not an
extraordinary unit, just a good solid one. There is a digital
coax output on the back, along with the standard analog RCA
output jacks, if you should decide to upgrade later. We tried
this out with an excellent outboard DAC, and the sound was
improved considerably (also meaning that the transport section is
a good one). But for a min-system, the inboard DAC is just fine.
In summary, if you are considering a mini-system for yourself, or
for your dormitory-bound college kids, this is a much better one
than you will find in the all-in-one-piece minis. Granted, they
do have loads of cute features (and cost less), but in the final
analysis, it is always how it sounds, not how many different
colors and readouts that shine from across the room. You won't
find an all-in-one that sounds like this kit. The components are
all good enough that upgrades can be made later, such as a more
powerful amp, outboard DAC, and so on . . . an idea that those
college kids might let you know about at graduation time.
John E. Johnson, Jr.
Editor
© Copyright 1995, 1996, 1997
Secrets of Home Theater & High Fidelity
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