DA-BM15A
OWNERS MANUAL
Congratulations on your purchase of the Dynaudio Acoustics BM15A monitor system. With
the right care and attention it will give you many years of trouble free audio reproduction. It is
most important, however, that you take a few minutes at this early stage in your BM15A’s life
to read the following paragraphs. They contain essential information to enable you to get the
best from your monitors.
Electrical Safety Warning
This unit is supplied with a 3 wire power cord. Under no circumstances should the
earth wire be disconnected.
To prevent possibility of shock hazard do not expose the unit to moisture
There are no user serviceable parts inside. Do not open cover. Refer servicing to
qualified personnel only
Ensure correct mains voltage and fuse are selected before connection to mains
Operation
Controls
Level switch.
This sets the input sensitivity of the unit. The +4 position is intended for
professional use and means that full power is reached with an input level of
+4dBm (balanced). The -10 position is intended for semi-professional or
domestic use and means that full power is reached with an input level of
-10dBm (unbalanced).
HF Trim
LF Trim.
This control allows the high frequency level to be adjusted. The HF Trim
circuit is a low-Q equaliser which reaches a maximum range of 6dB @ 15kHz
(see graph).
This control allows the low frequency level to be adjusted. The LF Trim circuit
is a low-Q equaliser which reaches a maximum range of 6dB @ 50Hz (see
graph).
The trim controls are intended to allow the user to make some adjustment of the speaker
response to accommodate personal tastes and variations in acoustic environment.
Trim Control Response
Indicators
There are two LED indicators on the front baffle of the BM15A.
The right hand one is the power/fault indicator. On switching the unit on this will shine red for
about five seconds and then turn green to indicate normal operation. If for any reason the
amplifier protection circuitry is engaged the LED will turn back to red.
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November 1997
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The left indicator is a 'true-clip' indicator and lights if the low frequency amplifier clips, or runs
into overload. It is acceptable to run the system with this lighting occasionally on peaks, but
avoid running the system with it lighting most of the time
Running-In
The drivers in your BM15A must be run-in before optimum performance is achieved. Avoid
using the system at high levels for the first 24 hours of operation. Full run-in is usually
achieved after about one week of normal operation.
Protection
The BM15A has a comprehensive electronic protection system. Thermal overload or dc
voltage on the outputs will cause the system to engage. This will disconnect the drive units
from the amplifiers and change the power LED to it’s red/fault condition. In addition the HF
amplifier has an optical limiter in circuit which prevents excessive long term power reaching
the tweeter whilst allowing transients to pass uncompressed.
Troubleshooting
If the speaker stops working and the power LED turns red (fault condition) switch the mains
power off and leave it for a moment. If the unit fails to operate again when you switch back on
the fault may be due to overheating, switch off again and allow it to fully cool down before
powering up. Ensure the heatsink is clear of obstruction and has free air circulation around it.
If however the fault condition persists the unit should be inspected by qualified personnel
(your DA dealer).
If the speaker stops working and no LED’s are alight then the mains fuse on the back panel
should be checked and replaced if necessary. If this does not rectify the problem the unit
should be inspected by qualified personnel (your DA dealer).
Care
Components of the highest quality are used in the BM15A. and should give a long trouble free
life. Here are a few hints to help them on their way.
Avoid running the system into more than very brief clipping or distortion. When an amplifier
clips it can send potentially damaging d.c. components to the drive units. They may not fail at
once but prolonged exposure to this will result in eventual failure.
Avoid unplugging or switching off any equipment that is connected to the monitor system
without first turning off the BM15A. Large voltage spikes are often generated when equipment
is switched off which will be amplified to a potentially damaging level.
Do not touch the drive units. The tweeter especially uses a very fine fabric diaphragm which
is easily damaged.
Options
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November 1997
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The BM15A may be used in conjunction with the Dynaudio Acoustics Active Bass Extension
System. The ABES comprises a single 2 x 12" Bass cabinet, with an integrated crossover
and amplifier mounted on the rear. The ABES will extend the frequency response of the
BM15A down to 35Hz. Please consult your local dealer for a demonstration.
Service
There are no user serviceable parts inside the BM15A so consult your dealer if service is
required or contact one of the addresses below.
Dynaudio Acoustics A/S
Sverigesvej 15
DK-8660 Skanderborg
Denmark
Tel: +45 86 52 34 11
Fax: +45 86 52 31 16
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November 1997
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Warranty
This product is guaranteed against defects in materials and workmanship for 1 year from date
of purchase. This warranty is void if the unit has been tampered with or modified in any way,
or in our opinion has not been used in accordance with the instructions above.
Technical Specifications
Type:
2 way active near/midfield monitor
Frequency Response: 40 Hz to 22 kHz (-3dB).
SPL (Peak/Cont.):
Drive units:
119dB / 109dB one cabinet @ 1m.
240 mm bass driver, 26 mm high frequency driver
200W + 100W discrete MOSFET power amps.
Convection cooled.
Internal amplifiers:
1.7 kHz electronic crossover, 5th order phase aligned.
Instrumentation type balanced input section, with input overload
protection.
Protection:
DC, Thermal on both channels, opto-electronic limiter on HF
Variable HF and LF trim, Input sensitivity
455 x 290 x 387 millimetres (h x w x d)
User Controls:
Dimensions:
(Allow 35 mm for rear connectors clearance)
Free standing near/mid-field, desktop mounting.
Rigid high performance stands recommended.
Power cable supplied.
Positioning:
Accessories:
Schematic Diagram
100W Hexfet Amplifier
HF limiter
Instrumentation type
electronically balanced
input stage
DA D260
Fixed eq
LF and HF trim
5th order
crossover
Driver
protection
DA 24W100
Clip indicator
200W Hexfet amplifier
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November 1997
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