(09-02-2013 00:10)black_13 писал(а): Схема выбрана, будет Моррисон micro на лампе 2A3
Спасибо triumph76 за предоставленную информацию, а также другим отзывчивым и не очень ;-)
P.S. Ушел в медитации по выбору комплектующих .....
Один из лучших на 2а3:
Audio Amplifier
Transient waveforms should be transmitted
without distortion since audible
sounds have very important transient
characteristics. Percussion instruments
and staccato scores on the brasses demand
good transient response. A square
wave introduced into an amplifier and
viewed on a scope is a good test for
transient responses. Fig. 3 shows a
5000-cycle square wave through this
amplifier.
Good transient response is accomplished
by extending the frequency range
and having negligible phase shift
between input and output of an
amplifier.
Transformer resonance can cause
slight oscillations well above the audible
range. If the phase shift at these
oscillation frequencies is sufficient to
cause the feedback to become positive,
regeneration will take place, resulting in
sustained oscillations and overloading
of the amplifier at super-audible frequencies.
This can be avoided by
reducing the gain of the amplifier
above the useful frequency range, or by
preventing the occurrence of these
oscillations by proper design of the
output transformer.
The transformers are completely free
from saturation or leakage reactance
effects from 25 to 20,000 cycles at any
power up to maximum output. The
low frequency response is flat within 2
dB to 3 cycles. The extremely low
frequency response in the amplifier is attenuated
in the first stage to eliminate
the effects of transients in tuning a radio
receiver, or phonograph turntable eccentricity,
or rumble. Some amplifiers
for industrial application have made use
of this good low frequency response.
The low-frequency attenuation is accomplished
by using a condenser in
series with the input to the grid of
the first tube. The complete schematic
is shown in Fig. 4.
The output transformer is largely responsible
for the fine performance of the
amplifier. It looks like a simple
end-bell type of transformer, but
with larger-than-the-usual output
transformers. The amount of iron in the
transformer and the unique, very complicated
wind structure gives the transformer
no frequency discrimination and
negligible phase shift over the entire
audio range.
Negative Feedback
Everything possible was done to produce
a perfect audio amplifier without
using feedback. After this was accomplished,
11 dB of feedback was added.
This amplifier without feedback has as
good a frequency response as usual
high-fidelity amplifiers with feedback. In
other words, it does not depend entirely
upon feedback
for its 0.2 dB variation from 20 to
20,000 cycles.
The input impedance to the amplifier
is normally 0.5 megohms. An input
transformer is hermetically sealed. It is
well shielded from magnetic pickup by
having three nickel alloy shields. The
leads pick up more hum than the transformer.
Power is available for operating additional
preamplifiers or a tuner. The
voltages available are 6.6 volts at 5.5
amps, and 300 volts at 90 ma, DC.
The distortion at full output of 30
watts is less than 2.5 per cent. The
intermodulation distortion, or doublefrequency
results, are extremely low.
Taken at 24 watts at 50 cycles and 1.5
watts at 1000 cycles, the
intermodulation distortion is 1.7 per
cent. Taken at 4.7 watts at 50 cycles
and 0.3 watts at 1000 cycles, the
intermodulation distortion is 0.2 per
cent, referred to the 1000-cycle signal.
Listening tests carried out in conjunction
with a wide-range loudspeaker system
have fully supported the measured
performance. We could not detect distortion
in reproducing organ music including
25-cycle pedal notes. It
provides an ideal amplifier for
sound-recording purposes, FM
monitoring or anywhere else where
distortionless amplification is necessary.
AUDIO ENGINEERING • JUNE, 1947
Естественных дел мастер...
"...обучение редко приносит плоды кому-либо, кроме тех, кто предрасположен к нему, но им оно почти не нужно..." (Гиббонс)
... Питание кенотронное, дроссели, куча МБГВ 100*1000, и т.д. Схема, считаю самая оптимальная, минимум деталей - максимум качество трансов (и всего остального). Уже 3 года о ней мечтаю 
, но, потихоньку воплощаю в жизнь.
Теперь все упирается во время
...
![[Изображение: post_91_1360402332_36a52a7e21ef14853629e..._thumb.jpg]](https://hi-fi-forum.net/uploads/post_91_1360402332_36a52a7e21ef14853629e937c49a5e0d_thumb.jpg)
для начинающего 
