Teac W-520R - Dolby Hx Pro; Specifications

DOLBY HX PRO
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Dolby HX Pro is an "active bias" technique that can
improve the quality of audio tape recordings. High-
level high frequencies can be recorded more
accurately, without sacrificing the signal-to-noise
ratio, while such side effects of tape saturation as
distortion are reduced.
What Is Bias?
Bias is a very high-frequency signal generated within
a tape deck and recorded on the tape simultaneously
with the program material. This inaudible signal
allows low noise, low distortion recording and a flat
frequency response. Different magnetic tape
formulations require differeent amounts of bias for
optimum performance. If the bias level is too high,
the high-frequency Maximum Output Level (MOL)
decreases.
The Problem of Self-Bias
Unfortunately, the bias level is often influenced by
the signal being recorded. The high frequency
components of some music act as bias. This
unpredictable source of bias is added to the existing
bias, resulting in a loss of high-frequency response.
As the high-frequency contents of the signal
increase, the ability of the recorder to record high
frequencies (MOL) decreases. This phenomenon is
called self-iasing.
The Dolby HX Pro Solution
Dolby HX Pro monitors the high-frequency contents
of the program and adjusts the recorder's bias
oscillator to maintain a constant total bias level. The
result is improved high-frequency response and
lower distortion. Depending on the type of tape, the
improvement in headroom (dynamic range) can be 6
dB or more.
The Benefits
With Dolby HX Pro, it is easier to make more
accurate recordings of music which contains high-
level high frequency components. The improvement
is similar to that of high-performance tape over
conventional tape, and regardless of the type of tape
used, the results will sound better.
Most important of all, Dolby HX Pro requires no
decoding process. Once a tape is recorded with it,
the improvement will be realized when playing the
tape back on any machine.
+10, |
250nWb/m
HX PRO on
HX PRO off
40
20Hz 50 100 200
500 1k 2 5 10 20k
Example of improved frequency response using Dolby HX Pro function
a Fo
SPECIFICATIONS
Track System : 4-Track, 2-Channel Stereo
Heads : 1 Playback (Rotary, DECK |) 1 Erase and
1 Record/Playback (Rotary, DECK I!)
Type of Tape :
Cassette tape C-60 and C-90
(Philips type)
Tape Speed :
4.76 cm/sec (1-7/8 ips), 9.5 cm/sec
(3-3/4 ips) (High speed dubbing only)
Motors : 4; 2 DC servo motors and 2 DC motors
(2 ea. deck)
Wow and Flutter (WRMS) : 0.06 %
Frequency Response (Overall, -20 dB) :
25 - 19,000 Hz, Metal
25 - 18,000 Hz, CrOz
25 - 17,000 Hz, Normal
Signal-to-Noise Ratio (Overall) :
59 dB (NR off, 3% THD level, Weighted)
69 dB (Dolby B NR on, over 5 kHz)
79 dB (Dolby C NR on, over 1 kHz)
Fast Winding Time :
Approximately 110 seconds for C-60
Line Input : 87 mV, 50 k ohms
Output : Line; 0.46 V for load impedance of 50 k
ohms or more
Headphones; 8 ohms
Power Requirements :
120 V AC, 60 Hz, 21 W (U.S.A./Canada
model)
240 V AC, 50 Hz, 25 W (Australian model)
Dimensions (W x H x D) :
435 x 147 x 277 mm
(17-1/8" x 5-13/16" x 10-7/8")
Weight (net) : 4.9 kg (10-13/16 Ibs.)
Standard Accessories:
Input-output connection cords
© Specifications were determined using metal tape
except as noted.
e Improvements may result in specification or
feature changing without notice.