cuit. The flat signal is passed
straight through, and only when
an adjustment is required, the
characteris-
tics created
at F1 and F2
are added to
the signal,
thereby pro-
ducing the
d e s i r e d
change. This
design pro-
vides efficient
control with-
out degrading signal purity.
Large toroidal power transformer and high fil-
tering capacity
The power supply section is a critical aspect of
any power amplifier. The E-407 features a large
toroidal power transformer with a rating of 600
VA. The transformer is housed in a non-resonant
aluminum enclosure filled with damping material
that has excellent heat transfer characteristics.
Toroidal transformers which use heavy-gauge
copper wiring on a ring-shaped core have vari-
ous advantages, such as very low impedance,
small size, and high conversion efficiency. The
toroidal type transformer used by Accuphase is
ideally suited for audio applications. It has the fol-
lowing characteristics:
a
Near-circular core caliber allows near-circular
coil windings with high packing density, result-
ing in low leakage flux and minimum vibrations.
b
Smaller ferrite core diameter and copper
windings with high specific gravity mean low
ferrite losses and low inrush current.
Two massive electrolytic capacitors, each rated
for 33,000 uF assure ample reserves also for re-
production of the most demanding passages.
Dedicated headphone amplifier for best sound
The E-407 provides a separate
amplifier for the phone jack de-
signed to provide superior sonic
performance. The speaker out-
put can be cut off by a switch,
and the main volume control
can be used to adjust the
headphone listening level.
Two sets of heavy-duty
speaker terminals
The oversize speaker
terminals are made of
extruded high-purity
brass material which
accept also heavy-gauge speaker cable. Two sets
of outputs with a
speaker selector
are provided, and
bi-wiring (supply-
ing the same sig-
nal via dual leads
to speakers with
separate high-fre-
quency and low-
frequency inputs)
is also possible.
Large analog peak power meters
The power meters use logarithmic compression
to cover a wide dynamic range, letting you easily
monitor the output level of the rapidly fluctuating
music signal. Meter illumination can be switched
off, which is conven-
ient for example in
a home theater
setup.
n
Supplied remote commander RC-20
Allows volume control and source
switching
Power amplifier
assembly with tri-
ple parallel push-
pull output devices
mounted to large
heat sink and cur-
rent feedback am-
plifier circuitry
Heavy-duty speaker terminals
Figure 4 Tone control circuit principle
(Summing active filter type)
Massive filtering capacitors and
large toroidal power transformer
