The transformer is housed in a Mu-
metal shielding can that measures
51 mm in diameter x 60 mm in
height, excluding the connecting
leads. The input and output connec-
tions are made via mil. spec. silver
plated Teflon insulated copper wire.
The secondary (output) winding of-
fers 23 taps allowing the following
attenuation values:
0 dB, -3 dB, -6 dB, -8 dB, -10 dB,
-12 dB, -14 dB, -16 dB, -18 dB, -20 dB, -22 dB, -24 db, -26 dB, -28 dB, -30 dB,
-32 dB, -34 dB, -36 dB, -38 dB, -40 dB, -44 dB and -48 dB. The primary (input)
winding has a 0 dB and +1 dB taps. Combining the switching of primary and
secondary taps with the built in microprocessor firmware and the miniature reed
relays (50 pcs) we get the volume range b1 and -48 dB in altogether 45
steps! With this smart, new method the volume step is only 1 dB over the major-
ity of the range which is much smaller than the commonly acknowledged limit of
audibility (3dB), giving a su
ffi
ciently fine control over the volume, when com-
pared to continuous controls. Obviously, any attenuation is reliably repeatable.
The full primary has around 400 Ohm DC winding resistance. The resistance of
full secondary is 530 Ohm. The primary inductive reactance at 20 Hz is in ex-
cess of 100 kOhm (1100 H primary inductance) and thus provides an input im-
pedance of more than 138 kOhm across the audio band if the secondary load is
infinite.
The primary winding has a +1 dB tap which allows the very smooth 1 dB step of
volume control.
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TECHNICAL DETAILS
icOn Smart TVC preamplifier
