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INTRODUCTION
This new Citation basic amplifier kit represents the culmination of extensive research and experimentation in
the technique of kit design. It is meant to satisfy the aspirations of those who insist on nothing short of
perfection itself. The keynote is unparalleled performance and there has been no compromise made in the design
of this magnificent instrument. Although the Citation II will perform satisfactorily with any high quality
preamplifier, it is strongly recommended it be used with the Citation I or Citation IV stereo preamplifiers
control center for optimum performance. The Citation I and IV match the superb frequency res ponse and
distortion specifications of the Citation II resulting in uncompromising performance.
This instruction manual is written in simple, nontechnical language and if you will take the time to read it
thoroughly before starting the actual construction of this kit, your work will be easier and far more accurate.
Additional information may be obtained by carefully studying the large fold-out diagrams supplied with this
manual. These may be attached to the wall opposite your workbench for easy reference.
After studying the manual, work slowly and carefully. After every ten or fifteen steps, go back over your
work to check for possible errors. This will insure proper construction and will afford you the feeling of satis -
faction upon completing an amplifier that performs perfectly the first time it is connected.
KEEP THIS INSTRUCTION MANUAL AVAILABLE AT ALL TIMES FOR IT CONTAINS IN-
DISPENSABLE TECHNICAL AND SERVICE INFORMATION.
TECHNICAL DESCRIPTION
Extensive listening studies reveal that the behavior of a high fidelity amplifier several octaves above and
below the normal range of human hearing distinctly colors the reproduced sound. It has been determined that an
amplifier having a wide frequency response at useable power levels below 5 cycles has a tight and clearly defined
low end, particularly in the 40-100 cycles region.
A similar condition applies to the performance of an amplifier in the high frequency spectrum. If an am-
plifier limits its high frequency response to slightly above the limit of audibili ty, it may have a tendency toward
strident reproduction and poor differentiation of instruments in the high overtones. Conversely, an amplifier
which has a frequency response beyond 100,000 cycles without evidence of ringing or instability with reactive
loads will offer clean, transparent tone qualities in the higher frequencies with excellent instrument separation.
It is for this reason as well as other considerations that conventional power amplifier design has been by -
passed in the general design concept of this basic amplifier.
Current power amplifier design is based upon “single loop” feedback techniques, and linearization is ob-
tained by overall feedback from the voice coil terminals to the cathode of the input tube. Stability problems limit
this application to 20- 26 db of useable feedback, which represents a 101 to 201 reduction in distortion.
Careful listening evaluation of amplifier performance proves conclusively that extremely stable amplifiers
with higher degrees of feedback provide a noticeable improvement in sound quality and a definite reduction in
listening fatigue. This improvement can be attributed to lower harmonic and intermodulation distortion prod -
ucts, more linear phase characteristics, and improved transient response.
A “multiple loop” approach toward increasing the degree of useable feedback is the most logical approach to
lower distortion without sacrificing stability. These “multiple loops” become additive if their ratio is adjusted to
the relative degree of distortion produced. Thus, if one stage has twice the distortion of another, it should have
twice as much feedback around it. Experiment has shown that the equivalent of 30 db overall feedback is safely
reached by this approach.
It is essential to have a well regulated power supply in order to maintain clean transient response. The power
supply of this amplifier incorporates four Silicon Rectifier Diodes, which together with extremely low copper
loss in the power transformer provides regulation equivalent to that of a regulated supply. Leakage inductance in
the output transformers has been kept to an absolute minimum, and the distributed capacitance of the primary
halves have been carefully balanced against each other to maintain the natural resonances of the output
