This manual provides general, ongoing use and safety information for the VTA20S Stereo Amplifier also
known at the Black Magic 20 Stereo Amplifier.
GENERAL
The Black Magic 20 stereo amplifier is the perfect blend of form and function and the ideal choice for
serious music listeners. It is conservatively rated at 20 watts per channel in stereo mode and 40 watts in
monoblock mode.
This stereo amplifier offers outstanding performance that is difficult to believe, with a high impedance
input, an automatic DC restorer and bias circuit for each channel. Output tube idle current is very low,
which greatly increases tube life. It has ultra-wide bandwidth output transformers with interleaved wind-
ings capable of the most nuanced voice as well as huge peak output capacity.
From a listening perspective these amplifiers provide a warm, rich sound with a sumptuous and envelop-
ing sound stage, a great front to back depth of field, and very tight, pin-point imaging within that larger
acoustic. A special current feedback circuit allows the amplifier to “listen to the room” via feedback from
the speakers acting as microphones (using the law of reciprocity). The room-speaker-amplifier interac-
tion provides a sense of believable ambience and acoustic space that is thoroughly realistic and quite
enjoyable. Additionally, the transformer output impedance allows the signal to follow the impedance
curve of the speaker system, allowing more voltage to be delivered to the loudspeaker at very low fre-
quencies – providing an exceptional and satisfying low end response.
SAFE OPERATING CONDITIONS
Before connecting the amplifier up please read the following safe operating conditions.
1. Be cautious when lifting the amplifier. It weighs 19 pounds. Make certain that what it is placed
on can support the weight.
2. The amplifier should be situated so that its location or position does not interfere with its proper
ventilation. The amplifier should never be placed near or over a radiator or heat register. The
amplifier should not be placed in a built-in installation such as a bookcase or cabinet that may
impede the flow of air around the unit. Do not place this amplifier directly on carpeted floors.
3. Do not operate the amplifier plugged into an ordinary extension cord. Heavy duty extension
cords (16 gauge or heavier) have adequate wire size and will not overheat.
4. If you plan on plugging a pair of these amplifier into a switched outlet on a preamplifier be sure
that preamp outlets can handle 100 watts total.
5.
Never connect or disconnect inputs or outputs while the amplifier is turned on. Loudspeakers
can be damaged or destroyed by the high power available from the amplifier.
6. The output tubes do get hot when the amplifier power switch is on. Do not touch the output
tubes when the unit is on. If you need to change an output tube, wait 10 minutes after powering
the unit down before you touch the tubes.
7. Turn the amplifier off when not in use to save energy and extend the life of the tubes.
8. Additional safety information is located at the back of this manual.
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