National Horizon 20 Instruction Book

INSTRUCTION BOOK FOR
The
National
The latest in audio engineering techniques, plus
careful attention to design details, make the Hqrizon
20 an instrument unparalleled for superb performance
and operating efficiency. Its excellent characteris-
tics are due, in large measure, to the unique output
stage in which the coupling between the output tubes
is unity, independent of the output transformer. This
permits the use of high efficiency class ABj operation
without the impulse distortion commonly associated
with conventional circuits which rely upon the output
transformer for coupling between the tubes. Unity
coupling has the additional advantage of requiring a
TWENTY WATT
AMPLIFIER
far lower impedance ratio between the output tubes
and the load with attendant reduction in leakage in-
ductance and increased power bandwidth.
In addition to its superlative performance, the Na-
tional Horizon 20 incorporates the unique plug-in faci-
lity for the accommodation of the Horizon 5 Preampli-
fier — Control Unit. This feature alone exemplifies
the advanced design of the National high fidelity line
resulting in optimum flexibility of installation and
operation. The following specifications indicate some
of the other outstanding features of the Horizon 20.
Please use this manual. It has been prepare*/ with the prime p urpose of enabling the user to obtain
full satisfaction from this product.
NATIONAL COMPANY, INC., MAIDEN & MELROSE, MASS.