Bryston BP-20 User manual

setup Recommendations:
Congratulations on your purchase of a Bryston
preamplifier. We are confident it will provide you with
many years of musical enjoyment.
You may place your preamplifier in any conive-
mient location, with two possible exceptions. If you own
the Bryston BP-25 remote-control version, position the
preamplifier to maintain a direct line-of-sight between the
hand-held remote and the remote sensor eye located on
the left side of the preamplifier’s front panel.
If you purchased the BP-25P or BP-25MC,
which includes a Phono section, avoid placing the pream-
plifier directly on top of your power amplifier.. Power
amplifiers usually employ large power supplies and the
transformer(s) in the power supplies can cause interfer-—
ence (hum) with the sensitive phono section inside the
preamp. |
BP-PS Power Supply:
The BP-PS outboard power supply provides AC
power for the BP-20 and BP-25 preamplifiers. It has a
slide power switch located on the front and a green LED
to indicate power on.
On the rear of the unit is a three-position con-
nector which provides a control voltage for remote turn
on/off of your Bryston THX amplifier(s) or other ampli-
fiers so equipped. This feature can be used in two ways
depending on the wiring arrangement utilized:
Option one provides for the preamplifier and
power amplifier to be turned on or off when you
operate the power switch located on the front of the
external power supply. Turning the power off with the
switch on the outboard power supply removes AC power
Connections:
Connect the preamplifier’s left and right outputs
from either the RCA or Balanced XLR connectors to the
appropriate left and nght input jacks on your power
amplifier. Balanced cables are an advan if you are
using long runs of cable, (greater than 20 feet), between
your preamplifier and power amplifier.
~ Connect your CD player, tuner, tape deck, video
recorder, or laser disc, etc. to the specific left/right pream-
plifier inputs. With phono-equipped models, (BP-25P or
BP-25MC), connect your phono cables to the phono
input jacks. If your turntable leads have a separate ground
wire, it may be connected to the ground lug adjacent to
the phono inputs on the rear panel.
Next, insert the 5-pin din cable from the out-
board power supply into the input connector located on
the rear of the preamplifier. Then plug the power supply
into an appropriate AC power outlet. The preamplifier 1s
powered up by engaging the slide switch located on the
front of the extemal power supply. The “green” LED on
the outboard power supply and the preamplifier front
panel indicates power-on.
If the preamplifier has been placed in the “mute”
position operating the volume up button on the
remote will automatically un-mute the BP-25 pream-
plifier, turning the LED from red to green. On the
BP-20 you must manually activate the mute toggle
on the front panel. Both the Mute switch and the
Polarity Invert switch are momentary-toggle types, oper-
ated by push-and-telease.
from both the preamplifier and the power amplifier(s) for
complete system shut-down.
Option two allows the power amplifier(s) to
be turned on or off with the mute button on the
hand-held remote control unit or the mute toggle on
the front panel of the preamplifier. This will shut down
your systern “for the mght’, completely removing power
from the amplifiers, but leaving the preamp in the Mute/
standby mode, indicated by the red LED on the prearpli-
fier’s front panel.
Please refer to the diagram on the included
separate instruction sheet for further clarity and optional
wiring afrangements.
The Bryston BP-20 and BP-25 preamps also
feature two pairs of balanced XLR input jacks. Many
signal sources, including CD-players and separate D/A
converters are now available with Balanced outputs for
munimum noise pickup on the cables.
The tape loop may be used to insert a surround
sound processor, cassette tape deck or video tape recorder
into your system. Plug your tape deck or extemal proces-
sor’s imput cables into the “To Tape’ jacks, and the proces-
sor or deck’s output cables into the ‘From Tape’ jacks at
the rear of the preamp. The tape or processor loop may
be operated via the toggle switch located on the front
panel of the preamplifier.
Page 2

Input and Output Connectors:
Bryston preamplifiers are equipped with five
paits of RCA input connectors, two pairs of balanced
XLR input connectors and one pair of RCA tape input
jacks. The balanced inputs, (pin-1 ground, pin-2 post-
tive and pin-3 negative). All inputs employ fully dis-
crete active input circuitry. Two pairs of RCA main
outputs, one pair of RCA tape outputs and one pair of
balanced XLR outputs are also provided.
All input and output connectors on the BP-20
Bryston BP-25 Remote Control:
The Bryston model BP-25 is supplied with a
hand-held remote control unit. The remote features in-
clude Volume control, Mute, and Polarity Invert. All
remote control functions may be operated manually from
the front panel of the preamplifier 1f desired.
The Volume Control is a motor-driven design.
This approach ensures the lowest distortion with maxt-
mum long term reliability.
The Polarity-Invert switch allows you to reverse
the absolute phase of the audio signal, (not to be confused
with left-versus-right channel phase), because polarity
reversal can occur in the recording chain. (In fact, our
investigations show that polarity is not consistently main-
tained in commercial recordings). It is desirable to main-
tain absolute phase as originally played in the recording
Bryston MMM and MC Phono Section:
Bryston’s Phono section 1s available in the BP-20
or BP-25 preamplifiers. It features state-of-the-art accu-
racy in equalization, extremely low noise and distortion,
and provides headroom margins sufficient to prevent
overload from any known phono source.
| The Phono section may be ordered in either of
two versions: Moving-Coil, (Model BP-20MC or BP-
25MC), or Moving-Magnet, (Model BP-20P or BP-25P).
The BP-20MC and the BP-25MC provides a front panel
switch to choose the additional gain required for moving
coil cartridges Gee diagram page 4).
To access the Phono section on theBP-20MC or
BP-25MC, simply plug your tumtable interconnect leads
into the Phono ‘inputs on the rear panel of the preampli-
fier . Engage the MM/MC Phono togple-switch located
on the front panel of the preamplifier to the appropriate
moving-magnet or moving-coil position and tum the
“Source” rotary selector knob on the front panel to
and BP-25 are gold-plated. Only cables with high
quality gold plated connectors should be used with
your pteamp to avoid noise and distortion from the
corrosion which will eventually appear on poorly
plated cable connectors.
Bryston offers RCA or XLR cables with con-
nectors gold-plated to 20 microinches, (up to 30 times
heavier than standard gold-flashed cables). Standard 1
and 2 meter, or custom-length cables, are available.
hall, as that will provide the most accurate representation
of the original wavefront. This may be audible in some
cases as a more realistic rendition of musical transients
when the proper polarity for that recording is selected.
The Bryston BP-20/BP-25 preamplifiers maintain non-
inverting polarity at the Main output for all inputs when
the pilot light is green, and inverting polarity for all inputs
when the LED 1s yellow. The “lo Tape’ outputs are
always non-inverting.
The Mute control mutes the output of the
preamplifier to allow for interruptions without affecting
the volume control setting. (Refer also to the Power
Supply section of this instruction sheet for information
regarding remote Amplifier control via the Mute switch).
Phono. (Please ensure the MM/MC switch is in the
correct position for your cartridge, or your system will
display audible problems, such as poor frequency te-
sponse, low output, or both). If your turntable provides a
separate ground lead, system noise may be minimized by
connecting it to the ground lug adjacent to the phono
inputs on the rear panel. |
The BP-20P and BP-25P hookup procedure 1s
similar, with the exception that there is no front panel
switch between MM and MC. (This is replaced with the
Stereo/Mono switch).
The Bryston BP-20 and BP-25 are line-level
preamplifiers only. You may acquire Moving-Magnet or
Moving, Coil phono capability by returing it to the factory
for updating. We also offer the Moving-Coil setup stage,
as an outboard unit (IF-1), if your preamplifier already
contains a Moving-Magnet phono section.
Page 3

BP-20 Front Panel
VOLUME
OUT
BP-25 Froni Panel
VOLUME
BPRES

BRYSTON PREAMPLIFIERS
BP-25 and BP-20 Functions:
MPS-1 POWER SUPPLY : LED indicates GREEN when
power on. Provides 12-Volt supply for remote turn-on of
Bryston THX power amplifier(s) or others so equipped.
PREAMPLIFIER LED: Indicates RED when output muted.
GREEN indicates output is non-inverting polarity. YELLOW
indicates output has inverted polarity.
HEADPHONE OUTPUT (BP-25):
Allows monitoring of any input source with the use of head-
phones. It is recommended that you use headphones with input
impedances greater than 50 ohms for optimal performance. If
you wish to mute your loudspeakers while listening to your
headphones simply engage the MUTE switch on the preamphi-
fier (LED turns red). Be sure #of to use your remote control
(use the front panel volume control) to adjust the volume while
listening to your headphones, as the remote will ‘unmute’ the
preamplifier on ‘volume up’.
FRONT PANEL CONTROLS:
MUTE/NORMAL TOGGLE: Mutes or releases mute at
the main outputs, (not “To Tape’ outputs), without changing
the volume control setting, each time pushed.
POLARITY/INVERT ‘TOGGLE: Reverses polarity at main
outputs each time pushed. (GREEN LED indicates positive
polarity, YELLOW LED indicates inverse polarity).
VOLUME: Rotary control varies the output level to the
‘MAIN OUTPUTS’, (does not effect “TO TAPE’ outputs).
BALANCE: Rotary control adjusts the left-versus-nght chan-
nel levels. The Balance Control is a tailored-inflection type
which has very gradual action near the center of rotation
allowing fine adjustments to the stereo mage. For convenience
the electncal center of the control is detented.
SOURCE: Rotary knob, determines which input will appear at
the “TO TAPE’ outputs for recording or processing, as well as
determining which program is available at the Main outputs.
(When the “TAPE/SOURCE’ switch is in ‘Tape’ position,
“TAPE FROM? inputs appear at Main Outputs).
MONO/STEREO SWITCH: ‘Stereo’ position provides
two-channel stereo at the Main outputs. ‘Mono’ position sums
the main outputs to monaural. The “TO TAPE? outputs are
always stereo. (Switch not present on BP-25MC),
PHONO SWITCH (BP-25MC only): Allows the selection
of either Moving-Magnet or Moving-Coil phono. (BP-25MC
preamplifiers are equipped with a Phono MM/MC switch in
place of the Mono/Stereo switch).
TAPE/SOURCE SWITCH: Source (down) position moni-
tors whichever input is selected at the rotary SOURCE selector
knob. Tape (up) position provides monitoring of the ‘FROM
TAPE’ input for A/B comparison with the source. Should an
external processor or equalizer be connected in the TAPE
LOOP, the “TAPE/SOURCE” switch will act as an in/out
switch for the external equipment.
REAR PANEL CONNECTORS:
BALANCED OUTPUTS: Output is taken from the three-
pin “XLR” type connectors. Pin-1 is ground - Pin-2 is the
positive (+) output and Pin 3 is the inverted output. The
output is “ACTIVE BALANCED” (no transformer). Never
connect pin 2 or pin 3 to each other, to pin 1, or any
ground. ‘The outputs are capable of driving 30 volts to any
load 600 ohms or greater in balanced operation.
UNBALANCED OUTPUTS : There are two parallel unbal-
anced outputs for each channel available, utilizing gold-plated
RCA-style connectors. The output is always in-phase with the
input, and is capable of delivering 15 volts into any load of 600
ohms or greater.
TO-TAPE-FROM: The ‘TO TAPE’ outputs are selected by
the rotary “SOURCE” knob and are provided as a recording
output. This feed is unaffected by the operation of other front
panel controls. The ‘FROM TAPE’ (unbalanced RCA) input is
useful for monitoring tape playback or processed signals. Mov-
ing the “T'ape/Source” toggle to ‘Tape’ (up) position monitors
the recorded signal on recorders equipped with a separate
playback head, or the processed signal when using a signal
processor. Input sensitivity is 500mv, input impedance is 10K
ohms .
UNBALANCED INPUTS: Input connectors are gold plated
RCA Phono jacks. Input sensitivity is 500mv, input impedance
is 50K ohms. On BP-25P, Phono input impedance is 47K,
sensitivity is 5 mV. On BP-25MC, MMohms. Phono input is
as above, MC Phono input impedance is 180 Ohms, sensitivity
is 0.35 mV.
BALANCED INPUTS: Balanced input connectors are gold-
plated 3-pin “XLR” style connectors. Pin 1 is ground, Pin 2 is
positive input (+) and pin 3 is the inverting input (-). Input
sensitivity is 1 volt, input impedance is 15k
Page 5

BRYSTON LTD.
P.O. BOX 2176
677 NEAL DRIVE
PETERBOROUGH, ONTARIO
CANADA.
KSJ 7Y4.
Bryston products are warranted to be free from
manufacturing defects for a minimum of twenty
years from the original date of manufacture.
This includes parts, labour and return shipping
to the first owner and all subsequent owners.
Warranty coverage is automatic and com-
mences with the original date of manufacture
which is kept on file at Bryston.
In the event of a defect or malfunction, Bryston
will remedy the problem by repair or replace-
ment, as we deem necessary, to restore the
product to full performance.
This warranty is considered void if the defect,
malfunction or failure of the product or any
component part was caused by damage (not
resulting from a defect or malfunction) or
abuse while in the possession of the customer,
tampering by persons other than factory-
authorized service personnel, or failure to com-
ply with Bryston operating instructions.
This warranty gives you specific legal rights
and you may also have other rights which may —
vary from province to province and country to
country.
¢ BRYSTON SERVICE IN CANADA:
24 STEINWAY BLVD., UNIT 48
ETOBICOKE, ONTARIO
MSW 6T3
PHONE: [phone]
FAX: [phone]
e BRYSTON SERVICE USA:
79 COVENTRY STREET
NEWPORT, VERMONT
PHONE: [phone]
FAX: [phone]
° BRYSTON SERVICE OUTSIDE CANADA:
CONTACT YOUR LOCAL DISTRIBUTOR
: OR:
CALL BRYSTON DIRECTLY AT:
PHONE: [phone]
FAX: [phone]
www.bryston.ca