Page 2
1970 Tandberg series 3000 X
At 1 ips we are still within specification with a remarkably flat curve, whi\
ch, interestingly enough, is rising
between 8,000 and 10,000 Hz to give plus 3.5 dB at the latter frequency.\
Good as these figures are, they become even more meaningful when examine\
d in relation to the overall
response curves, in the production of which we used the 7-inch spool of \
Tandberg long-play low-noise tape
provided with the machine.
These results indicate a very, very, high standard of performance, guara\
nteeing the reproduction of
commercially pre-recorded material to professional limits of accuracy an\
d ensuring that recordings made on
the machine itself will be equally good at 7½ ips, while still retain\
ing an excellent quality potential at half that
speed. Even at 1
ips the frequency response curve indicates that on the 3000X this highl\
y economical
running speed could be considered for some kinds of musical repertoire.
But, as we have said so often, frequency response is by no means the beg\
inning and end of the matter.
Equally important are distortion and noise and so, as usual, we examined\
these two aspects together.
Firstly we confirmed that the distortion levels on both channels are vir\
tually identical, and at 7½ ips the record-
to-playback distortion at reference level (which coincides with a zero \
reading on the two built-in record level
meters) was exactly 3%, conforming to our own standard for tape recorde\
r high fidelity reproduction. When
working at the slower speeds it was found that at both 3¾ and 1
ips 5% distortion was reached when the
input signal was increased by 4.5 dB.
Measuring noise levels against these distortion parameters, we found tha\
t on the low noise tape provided, and
working with tape erased on the machine itself, the unweighted value at \
7½ ips was 52.7 dB, while the A scale
measurement was 60.7 dB. Working to 5% distortion at the slower speeds, \
the figures at 3¾ ips were 55 dB
unweighted and 63.5 to the A scale, at 1
ips 56.5 dB unweighted and 63.2 to the A scale.
Published specification figures refer noise to 5% distortion at 7½ ip\
s and therefore cannot be related directly to
our own measurements, which in conformity with other reviews have been r\
eferred to the 3% distortion level
at the tape speed. We believe this to be far more realistic. A notorious\
attribute of figures is their ability to
prove anything, depending on how they are expressed, so we can best summ\
arize our noise and distortion
findings by describing them quite unequivocally as representing some of \
the best performance standards we
have ever encountered in equipment of this kind and price.
Speed stability is the next important requirement and here it was found \
that when running at 7½ ips a 1,000
Hz tone was counted out electronically at 998. This represents a degree \
of accuracy so close to the absolute
that it could be regarded as 100%. At both slower speeds our readings we\
re 1.2% slow, a figure well within
the specified plus or minus 1.5%.
As usual, we checked wow and flutter at the beginning, middle, and end o\
f a 7-inch spool of tape and were
delighted to find that substantially the same readings were obtained at \
each of the three test points. The RMS
readings were found to be: at 7½ ips 0.1%; at 3¾ ips 0.125%; and a\
t 1
ips 0.21%. When measured
according to the DIN standard 45 511, the equivalents are at 7½ ips 0\
.08%; at 3¾ ips 0.12%; and at 1
ips
0.20%. No better tribute could be paid to the efficiency of this well-tr\
ied Tandberg tape transport mechanism
than the evidence of these consistently excellent figures.
We must here refer to the presentation of the manufacturer's specificati\
on, which clearly sets out his
statements of the machine's performance capabilities. It was commented i\
n the laboratory that one could
summarize the efficiency of the sample submitted for review by merely gl\
ancing at the specification and then
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