Dynamic Precision BPC 7.3 User manual

USERS GUIDE
PASSIVE BALANCED STEREO
CONTROL UNIT
BPC 7.3

BPC 7.3
INDEX
UNPACKING page 2
GENERAL INFORMATION page 3
SWITCHES AND INDICATORS page 4
CABLES AND CONNECTIONS page 5
ADJUSTMENTS AND OPTIMALIZATIONS page 7
TROUBLESHOOTING page 8
TECHNICAL SPECIFICATIONS page 9
WARRANTY page 10
Page 1

BPC 7.3
UNPACKING
Please read the User Guide carefully before attempting to use this apparatus. The User Guide comprises
general and specific information on adaptations/adjustments to give you the best possible performance of
the apparatus.
Please store the packing materials for later use.
When the apparatus is unpacked, please check that it has not been exposed to any damage and that the
package contains the following items:
1 pcs Dynamic Precision BPC 7.3.
1 pcs users guide for BPC 7.3.
Note: Please reports immediately any damage, defects or shortcomings to your dealer.
Page 2

BPC 7.3
GENERAL INFORMATION
We congratulate you on your choice of the Dynamic Precision BPC 7.3.
The technical solutions are all based upon the best high quality switches, connectors and discrete
components available, and the company’s unique knowledge to achieve the best possible reproduction of
musical signals.
The BPC 7.3 is fully balanced and DC-coupled from input to output. BPC 7.3 is designed to be able to drive
relatively long cables, normally a problem what passive controllers concern. To achieve this we had to
reduced the output impedance to a level lower than 2.4 kΩ.
BPC 7.3 has a minimum input impedance of 5.5 kΩ. Please observe that valve equipped D/A converters
and/or MC-amplifiers equipped with coupling capacitors smaller than 0.1 µF may suffer from a bass level
reduction because of the low level input impedance of BPC 7.3. Consult the signal source users manual to
find out if the signal source is able to work with loads as low as 5 kΩ. It is equally important to be aware of
the fact that the input impedance of BPC 7.3 will rise to 10.5 kΩ. when the "LEVEL STEP -1dB" is in the
position marked -10 dB. The latter will lower the load of the signal source output and may in turn cause an
increase of the sub-bass level.
Dynamic Precision power amplifiers is designed to accommodate passive balanced configurations by
keeping the input capacitance between 100 pF and 200 pF (please consult the Users Guide for that
particular power amplifier). As a result of this, the cable length between BPC 7.3 and the power amplifier
can be extended compared to other power amplifiers normally having a higher input capacitance (500 pF to
1000 pF). The inter conductor capacitance for balanced cables is normally 100 pF - 120 pF per meter, and
this gives a combination of BPC 7.3 and a Dynamic Precision power amplifier the advantage to be
interconnected with cables as long as 9 meters and still achieve the similar affect on the treble level as
power amplifiers with an input capacitance of 1000 pF.
The resistive part of the input impedance, for power amplifiers is of minor importance.
From an audible point of view, it does not matter if the resistive input impedance for a power amplifier is
10 kΩor 100 kΩ, but what really matters when using passive controllers is to keep the capacitive load as
low as possible. The latter is achieved using interconnect cables as short as possible (between the pre-
amplifier and the power amplifier), and have the lowest possible input capacitance on the power amplifier.
Page 3

BPC 7.3
SWITCHES AND INDICATORS
Figure A. BPC 7.3 front panel.
SWITCHES
PROGRAM SELECTOR:
OFF: All inputs disconnected, and the output terminated in 100 Ω.
CD: Signal from the CD-player.
DAT: Signal from the DAT-player.
Phono: Signal from the turntable (NB! this input require a separate MC or MM amplifier).
AUX 1: Auxiliary input 1.
AUX 2: Auxiliary input 2.
LEVEL STEP -1dB
Fine volume control that attenuates the signal level for both channels from 0 to 10 dB in
steps of 1 dB
Switches marked «LEVEL STEP -1dB» is primarily fine-tuning of the signal levels fed to
the power amplifier.
LEVEL STEP -10dB:
Master volume control that attenuates the signal level for both channels from 0 to 50 dB in
steps of 10 dB.
Maximum level attenuation is 60-dB pr. channel.
INDICATORS
BPC 7.3 is not equipped with any indicators.
Page 4

BPC 7.3
CABLES AND CONNECTIONS
Figure B. BPC 7.3 back panel.
CONNECTIONS
BALANCED OUTPUT
R OUTPUT: Balanced output right channel, XLR male connector.
L OUTPUT: Balanced output left channel, XLR male connector.
BALANCED INPUTS:
CD L and R: Balanced input left and right channel for the CD-player, XLR female
connector.
DAT L and R: Balanced input left and right channel for the DAT-player, XLR female
connector.
Phono L and R: Balanced input left and right channel for the phono amplifier, XLR female
connector.
AUX1 L and R: Auxiliary input 1, right and left channel, XLR female connector.
AUX2 L and R: Auxiliary input 2, right and left channel, XLR female connector.
Page 5

BPC 7.3
CABLES AND CONNECTIONS
AUDIOCABLES
Balanced cables
BPC 7.3 is fully balanced from input to output. Balanced signal sources shall always be connected using
balanced cables as shown in figure 3. The benefit of a totally balanced system is that any noise
superimposed on the signal paths will be cancelled on the input. On the other hand, when using an
unbalanced system there is no control of the noise in the system. This may cause high level of out-band,
high frequency signals to be applied on the input terminals. Such high frequency signals could causes the
amplifier to be loaded by high output currents which may increase the inter-modulation and result in an
audible reduction of the overall sound quality.
Ubalanced cables
BPC 7.3 can not be used with unbalanced power amplifiers. Unbalanced signal sources may be connected
to BPC 7.3 using a "special cable" comprising two inner conductors and a shield. All conductors shall be
terminated in both ends as shown in figure 4.
Authorised dealers of Dynamic Precision’s products can help and advice you how to choose the
proper cables to be used.
11
22
33
XLR-Female XLR-Male
Figure 3. Balanced to balanced XLR-cable.
1
2
3
RCA-Male XLR-Male
Figure 4. Unbalanced to balanced cable.
Page 6

BPC 7.3
ADJUSTMENTS AND OPTIMALIZATIONS
ADJUSTMENTS
BPC 7.3 does not have any user operated adjustments.
OPTIMALIZATIONS
BPC 7.3 is equipped with an aluminium chassis to avoid electromagnetic influence from the internal signal
flow, a solution which makes it sensitive to external electromagnetic fields eg. power amplifier transformers
and the loudspeaker cables. Because of this we advice you to locate the BPC 7.3 at least 30 to 50
centimetres away from the power amplifier or other electromagnetic fields.
Page 7

BPC 7.3
TROUBLESHOOTING
SYMPTOM POSSIBLE CAUSE POSSIBLE SOLUTION
Noise when adjusting listening
volume.
RF-noise. Mains filter/ferrite core.
Noise when adjusting listening
volume.
DC voltage present on signal
source output.
Check if a DC voltage is present
on the signal source output.
Noise when changing signal
source.
RF-noise. Mains filter/ferrite core.
Noise when changing signal
source.
DC voltage present on signal
source output.
Check if a DC voltage is present
on the signal source output.
Hum. Faulty signal cable, the shield is
either broken or not connected.
Change the cable or connect the
shield. Please observe figure 3
and 4 at page 6.
Page 8

BPC 7.3
TECHNICAL SPECIFICATIONS
BPC 7.3
PROGRAM SELECTOR: 5 INPUTS, stereo balanced, CD-DAT-PHONO-AUX1-AUX2, and OFF-position.
LEVEL STEP-1dB: Fine adjustments for volume. Level change in steps of 1 dB.
LEVEL STEP-10dB: Master volume switch «LEVEL STEP -10dB» in steps of 10 dB.
LEVEL LINEARITY: < 0,1% for all level steps.
COMMON MODE
REJECTION RATIO:
< 60 dB @ 20 Hz-20 kHz
INPUT IMPEDANCE: 5,5 kΩwith switch «LEVEL STEP -1 dB» in position 0 dB.
10,5 kΩwith switch «LEVEL STEP -1dB» in position -10 dB.
OUTPUT IMPEDANCE: Max. 2,4 kΩwith switch «LEVEL STEP -10dB» in position -10 dB. (Inputs short
circuited).
Dynamic Precision reserves the rights to change or alter the specifications and/or the technical
solutions without prior notice.
Page 9

BPC 7.3
WARRANTY
DURING THE WARRANTY PERIOD
The warranty and purchasers/vendors contractual obligations are in accordance
with the Sale of Goods Act.
All warranties shall be void if any carelessness, misuse and/or unacceptable handling of the apparatus or
any other conditions, which may be ascribed to the negligence of the purchaser of this product.
If a claim is raised concerning the operation of this product, please return it to the authorised dealer
accompanied by a copy of the original purchase receipt and a brief description of the fault symptoms. The
purchaser is requested to leave their telephone number and/or address in the event the manufacturer needs
further information to resolve the problem to the purchaser’s satisfaction.
Manufacturer
Dynamic Precision AS
Industriveien 3
N-2020 SKEDSMOKORSET
NORWAY
Telephone: +47 95870959
Facsimile: +47 63877911
Web site: http://www.dynamicprecision.no/
Dynamic Precision
is the registered trademark of Dynamic Precision.
Page 10
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