2.5B
3
Amplifier
5
Gold plated locking banana plugs are available from
Bryston.
Spade lugs provide high contact area and secure
fastening. Lugs should be gold plated. Post
diameter is 5/16” (8mm ), lug width 5/8” (16 mm).
Gold plated spade lugs are available from Bryston.
Stripped bare wire up to 3 gauge can be inserted
through the hole in the binding post and held
in place by tightening the post knob. Additional
tightening pressure can be achieved using a coin
in the slots of the knob. Do not over tighten or the
binding post may become damaged. Note that
copper wire is malleable and may require further
tightening after the initial installation.
Connecting Audio Inputs
The Bryston Cubed amplifier can receive analog
audio from any preamp or surround processor with
volume controlled line-level outputs. Balanced XLR
and TRS as well as singled ended RCA inputs are
both available and can be selected using the Input
Select switch on the rear panel of the amplifier.
Balanced vs. Single Ended Input
The balanced input requires a balanced pre-amp
source. Balanced systems provide noise rejection
from external electrical interference, so cable
length can be very long—50 meters or longer. The
single ended or unbalanced input is provided for
pre-amps without balanced output. Single-ended
cables should be kept to 20 feet (6 meters) or less.
In general never use longer cables than necessary,
never coil excess cable length, and keep signal wires
away from AC power or speaker cables.
Power Conditioners
Bryston urges caution in choosing a power
conditioner for your audio/video system. Large
power amplifiers can draw very substantial current
from the wall plug, and many so-called power
conditioners can in fact hinder the supply of current
by inserting resistances in series with the line cord.
However, there are now power conditioners that
can reduce or eliminate RF and ‘hash’ from the
AC supply and may actually
improve current delivery to
your system. This type of power
conditioner (exemplified by
Bryston BIT products) uses
the energy storage in a large toroidal transformer
to provide high instantaneous power and reduce
the substantial AC output resistance of the wall
socket and house wiring. This resistance can be in
the range of 0.5 to 1 Ohm and is typically reduced
to only a few milliohms by the power conditioner.
That in turn considerably reduces voltage drop in
the power line on high current surges and quite
substantially increases the stability of the power line
improving audio (and video) focus, precision and
clarity.
External Control Voltage
To power-up the amplifier using an external control
voltage, supply a 5V to 12V (AC or DC) control
voltage to the ‘IN’ terminals of connector (
fig. 1
). Use
paired wire of 22 to 18 gauge between the source
device and the Bryston Cubed series amplifier. The
appropriate mating connector is supplied with each
amplifier.
Place the front panel switch in the OFF position. The
amplifier will now power-up only when the control
voltage is present (on). Immediately following
power-up, the control voltage will appear at the
’OUT’ terminals of connector for the control of other
equipment. The removal of the control voltage (0v)
causes the amplifier to turn ‘off’, and the control
voltage at the ‘OUT’ terminals is interrupted.
When the front panel power switch is pressed in,
the amplifier will remain powered on regardless
of voltage present at the connector. If a control
voltage is present at the ‘IN’ terminals, it will still be
available at the ‘OUT’ terminals after the power-up
sequence.
Note: The ‘OUT’ terminals are connected to the
‘IN’ terminals once the amplifier has powered-up.
The control current is determined by the source
equipment. The carrying current of the ‘OUT’ relay
