|230,000 yen(June, 1987 release)
Channel dividers which added the balance input-and-output circuit and have
improved over details as part of the formation of balance transmission which the
Accuphase was promoting based on F-15.
The input-and-output circuit for
balance transmission is carried, the object form signal of negative phase is
made from the same voltage for the signal transmission between apparatus, and it
transmits by 3 core cable.
The multichannel divider consists of
combination of an active filter and buffer amplifier, and seven buffer amplifier
has protected the interference before and behind a circuit in F-15L.
Moreover, in F-15L, all the unit amplifier is the amplifier of the identical
configuration by the gain 1, and the active filter amplifier which makes the
crossover characteristic is 2-5, and has made the expected characteristic with
combination with CR element.
Unit amplifier has composition of the
complimentary push pull according [ the source follower of low noise high gmFET
complimentary and an output ] to a broadband transistor in an input in the push
The feature of this circuit does not have a loop return, the
element was selected carefully, it is being able to acquire the characteristic
which was excellent with the push pull system and the local feedback system, and
the low distortion is secured over a large zone.
With output unit
amplifier, in order to prevent generating of direct-current ingredient and to
attain stabilization, direct-current servo is given.
The basic structure of
a circuit is the same as unit amplifier, with output unit amplifier, servo
amplifier is added further and the damping time constant is decided by C and R.
With this cure, all the unit amplifier operates as direct-current amplifier
without a coupling condenser, and serves as a design focused on sound quality.
The level control of mid [ a right-and-left independent type low / ] /
high is carried in the front panel, it cannot be dependent on power amplifier
and the level control of each compass can be intensively performed in respect of
the panel of F-15L.
The Attenuator is a precision 1dB step type, and also
since it carries the 0.5dB shift switch, control of a 0.5dB step is possible for
it by combination.
An adjustable range is 41 points of 0dB--20.5dB and
A change of crossover frequency is made by substituting the
crossover board only for each frequency.
For the element which has big influence on sound quality, it constituted
centering on precision metal tunic resistance and a good silvered mica
condenser, and degradation and coloration of sound quality are prevented for it to the minimum.
Since a crossover
board changed cost with frequency, it had become option treatment.
since it is the same as that of the crossover board F-5 and for F-15, it can
The cutoff attenuation slope can choose two kinds, 12 dB/oct and
18 dB/oct, with a changeover switch.
3D system is supported and the
switch for it is carried in the rear panel.
If a crossover board is
substituted by an operating state, a speaker may be damaged for a shocking
In F-15L, in order to protect a speaker, just before a board
separates from a socket electrode, muting carries out differential, and the
protection circuit which intercepts an output is built in.
When using in
two ways (by amplifier system), 2 way-ization can be performed by inserting
attached 2 way board in inside and a loud-sound board socket.
When using as
four ways or five ways, it is possible by adding one more set of F-15L.
The rosewood cabinet for exclusive use was an option.
|The maximum input (distortion 0.01% or less,
20Hz - 20kHz)
||0.003% (20Hz - 20kHz, output 2.0V)
||20Hz-20kHz+0 -0.2 dB
(Single channel equivalent zone)
||It changes by substitution of a crossover
Standard frequency: 21 points
||- 12 dB/oct and -18 dB/oct Change type
|Output load impedance
||Unbalanced: 100ohms (Low/Mid/High)
Balanced: 50ohms (Low/Mid/High)
|Minimum load impedance
||100dB (Output 0.5V, A-compensation)
||0dB--20.5dB, a 0.5dB step
|The semiconductor used
||Transistor: 100 pieces
FET: 56 pieces
IC: 22 pieces
Diode: 58 pieces
|Power supply voltage
||Width 445x height 109x depth of 373mm
||Exclusive wood cabinet A-12 (\16,000)