NOTE: MATCHLESS amplifiers are biased
hot
and should not be allowed to idle with no
input signal for long periods of time. Use the STAND-BY function or shut the amplifier off
during prolonged rest periods.
3. Tube type amplifiers are inherently sensitive to speaker impedance matching.
This is due to the relationship of the internal resistance's of the output transformer, the
output tubes, and the load they are required to drive. A load imbalance can cause loss of
power, self oscillation, or excessive current to flow in the output stage. In severe cases this
condition can cause the output transformer to run hot and may damage or destroy the
output tubes. This kind of damage is not covered by a warranty. The impedance switch,
located at the rear of the chassis, is used to match the amplifier to the speaker load. This
rotary switch has three positions and can match the amplifier to four, eight, or sixteen
ohm loads. This switch should be set before the amplifier is turned on. MATCHLESS
single and four-ten cabinets are normally eight ohms. Dual speaker models are normally
four ohms.
When it is desired to use additional speakers with an amplifier, or multiple
speakers with an amp head, it is necessary to calculate the proper impedance
setting. This is easily accomplished using a simple Ohm's law formula:
The correct setting for two 8 ohm cabinets connected in
parallel
should be the four ohm
setting at the amplifier. It is also possible to connect speaker systems of unequal
impedance values using this same formula, simply set the impedance switch to the value
closest to the result. Remember that volume output may also be unequal, as the lower
impedance speaker is likely to be slightly louder because it demands most of the power
from the amplifier. Also be sure the power handling capacity is adequate.
POWER SOAK DEVICES
The use of "power-soak" devices is not recommended on your amplifier. These
devices can severely shorten the life of the output tubes which
should be replaced as a
matched quartet.
Replacing vacuum tubes can be quite expensive. If however one of
these devices is an integral part of
your
sound, choose one that is well designed and built
by a reputable company. When the amplifier starts to sound
dull
, it's time to replace the
output tubes.
Always replace tubes with premium quality
tubes
only!
Cheap tubes will
not sound good and will not last. MATCHLESS sells replacement tubes for all models.
Please contact your dealer or call the factory.
3
