B&K Reference 220M User manual
Reference 220M
Sin
g
le Channel Amplifier
OWNER’S MANUAL
B & K Components Ltd.
13005 rev 0004
13005 rev 0004
B&K Components, Ltd., 2100 Old Union Road, Buffalo, New York 14227
Page 1 13005 rev 0004
Table of contents
Safety Precautions Page 2
Purpose and function Page 3
Design and construction Page 3
Features Page 3
Rear panel view Page 4
Rear panel description Page 4 - 5
Control muting Page 5 - 6
Level controls Page 6
Outputs Page 7
Inputs Page 8
System installation Page 9
Making the connection Page 9 - 10
Troubleshooting Page 11
Care and cleaning Page 11
Specifications Page 12
Warranty page 13
Accessories included: Manual and Power cord
Page 2 13005 rev 0004
SAFETY PRECAUTIONS
PLEASE READ BEFORE INSTALLING
WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS UNIT
TO RAIN OR MOISTURE.
The li
g
htnin
g
flash with arrowhead, within an equilateral trian
g
le, is intended to alert the
user of the presence of uninsulated “dan
g
erous volta
g
e” within the product’s enclosure
that may be sufficient ma
g
nitude to constitute a risk of electric shock to you.
The exclamation point within an equilateral trian
g
le is intended to alert the user of the
presence of important operatin
g
and maintenance (servicin
g
) instructions in the
literature accompanyin
g
the unit.
Observance of polarity is essential. Double-check connections before turning the
amplifier on. The amplifier can be damaged if polarities are incorrect.
Damage can occur to your speakers if the power rating* of each individual driver
is exceeded by the amplifier. Ensure that all the drivers in your speaker system
are capable of handling not only the power being delivered by the amplifier, but
the energy that is likely to be generated during strong passages.
Turn amplifier ‘off’ when plugging in or unplugging input and speaker cables!!!
The Reference 220M is equipped with raised feet so that continuous ventilation
can be maintained. They help to maintain acoustic feedback into the amplifier at
a minimum. They also provide a measure of protection against scratching any
surface the unit might be resting on. Do not alter or remove them.
Do not stack anything on top of the amplifier (preamplifier, processor,
source...etc.).
Leave at least 2-3 inches clearance from the top of the amplifier to the next shelf,
component, etc., to ensure proper ventilation.
* If you are at all unsure of what the speaker ‘ratin
g
s’ are, contact your dealer.
Page 3 13005 rev 0004
The Reference 220M's purpose and function
The Reference 220M is a compact, very efficient, single channel power amplifier. It is
designed to be used in all types of audio or audio/video systems.
Design and construction
The Reference 220M utilizes high quality electronic circuitry to achieve an environment
wherein a detailed, transparent, and highly musical sound can be realized. The high
quality parts complement include state-of-the-art solid state devices, 1% metal film
resistors, computer grade electrolytic power supply capacitors, and a high capacity
toroidal transformer.
The Reference 220M operates class A predriver and AB high current MOSFET power
output stages. It is capable of reproducing the most demanding audio signals at rated
power levels. Features
Toroidal Transformers - Efficient high current transformer for improved dynamics.
Discrete Circuitry - More accurate and three dimensional reproduction of source
material.
Class A Predriver - Improves low level detail for smoother, more musical sound.
AB MOSFET Output Stage - For efficient and linear power delivery.
Limited Protection - Provides short term protection from accidental shorting of output
devices and protection from thermal overload.
Gold Plated Connectors - Improve connections for better sound and minimized signal
loss and degradation.
1% Metal Film Resistors - Low noise resistors for better sound and a greater degree of
repeatability.
High Current - Ability to reproduce demanding recordings.
Computer Grade Capacitors - Large capacity computer grade electrolytic capacitors
for extended low frequency control and improved dynamics.
Page 4 13005 rev 0004
Rear Panel View
1. AC fuse holder 5. RCA input (unbalanced)
2. AC Input receptacle 6. Level controls**
3. Speaker outputs 7. Amplifier control muting input/output
4. Balanced Inputs
** OPTIONS AVAILABLE FOR THE Reference 220M AMPLIFIER
Rear panel description
1. AC fuse holder - Holds the AC Line fuse. This fuse is an 12 Amp / 250 Volt
Slow Blow fuse. Replace with same type and value fuse
only.
2. AC Input receptacle - For attaching the supplied AC power cord to the
amplifier.
3. Speaker outputs - For connecting the speakers to the amplifier. Explained
further on page 7.
4. Balanced inputs - For connecting Balanced signal patch cables (XLR).
Explained further on page 8.
Page 5 13005 rev 0004
5. RCA inputs- For connecting signal patch cables (interconnects) from the
preamplifier to the amplifier to pass signal.
6. Level controls - Option available for the Reference 220M amplifier. For
adjusting the input level to the amplifier. Explained further
on page 6.
7. Amplifier control muting input/output -
To provide remote switching of mute on/off of the amplifier.
Explained further below.
Control muting
A control is provided on each Reference 220M amplifier to allow remote switching of
mute on/off. The preamplifier’s control output, such as is provided with B&K series
preamplifiers, can be utilized to provide a control signal to the Reference 220M. If more
than one amplifier is being controlled, the control signal can be extended to include
each successive unit by simply running a 3.5mm mini-jack cable from the CTRL OUT
connector of the first amplifier to the CTRL IN connector of the next unit (commonly
referred to as ‘daisy chaining’). An example of how to connect two amplifiers is
illustrated in figure B.
If a source other than a B&K series preamplifier is used to control multiple amplifiers,
only the control output voltage from the source is critical. It must be within the range, as
indicated on the rear panel, 5-24 volts DC is required. The amplifier will provide each
successive amplifier with a control voltage of 12 volts DC for reliable operation. The
amplifiers control output may be used as a source of 12 VDC @ 125 mA for other user
applications as well. DO NOT POWER MOTORS WITH THIS CIRCUIT.
Page 6 13005 rev 0004
)LJXUH&
If the control function is desired, each unit in the system must remain connected at all
times and the control must be enabled. To enable the control function, the CTRL
ENABLE button must be out for each controllable amplifier in the system. For more
information on the amplifiers output status under various control conditions, refer to the
table below.
@ CTRL IN Button position Output status @ CTRL OUT
Signal OUT Sound Signal
Signal IN Sound Signal
No Signal OUT Mute No Signal
No Signal IN Sound Signal
*Note: The control volta
g
e is for mutin
g
control only. Each amplifier must be connected
to its own source of AC power in order for it to operate.
Level controls
The level controls are an option that can be added to the amplifier. If your amplifier has
this option, the balanced inputs are not present. You can not have level controls and
balanced inputs on an amplifier.
There is one level control on the back of the amplifier.
When using the level controls, first start with them turned all the way up (clockwise).
Then adjust them according to your system requirements to match the sound level
coming from each speaker.
Page 7 13005 rev 0004
)LJXUH'
Outputs
Five wa
y
bindin
g
posts are provided. One pair for each channel. The
y
are desi
g
ned to
accept a banana-t
y
pe plu
g
or spade lu
g
connector (shown below) and are color coded
for eas
y
identification. The red (+) post should alwa
y
s be connected to the speakers (+)
jack. The black (-) post should alwa
y
s be connected to the speakers (-) jack.
Spade connector Banana
j
ack
Here is a t
y
pical amplifier setup
The Reference 220M amplifier has two sets of bindin
g
posts on it. The
y
are paralleled
inside the amplifier. The Channel 3 output is used for normal operation.
The amplifier comes standard with a Channel 1 and Channel 3 output. The Channel 3
output is used for normal operation, but
y
ou can use the Channel 1 output to connect to
another speaker in parallel.
Page 8 13005 rev 0004
Inputs
Unbalanced - RCA type connectors accept line input from the preamplifier’s
unbalanced output connectors. There are two input connectors, that
may be used to connect the amplifier to the preamplifier. The Channel
3 input is used for normal operation.
RCA cable connector -
Operation - For unbalanced operation, ensure the balanced switch between the
balanced inputs on the rear of the amplifier is in the ‘off’ (out) position. If
the amplifier does not have balanced inputs then it is always in
unbalanced mode.
Balanced - XLR type connectors accept line input from the preamplifier’s balanced
output connectors. The Reference 220M has balanced line inputs.
Balanced cable connector -
Operation - For balanced operation, ensure the balanced switch between the
balanced inputs on the rear of the amplifier is in the ‘on’ (in) position.
The Channel 3 input is used for normal operation.
If the amplifier is
equipped with level controls, the balanced inputs will not be
present.
Here is a typical input setup:
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