BMC Phono MCCI Manuale utente
Phono MCCI
Owner's Manual
B.M.C. audio GmbH
http://www.bmc-audio.com
1403‐EN
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Table of Content
Introduction, Content of Packing
Front Panel Functions
Rear Functions
Cartridge Selection
Balanced Phono Cable, Basics
Caution! Dangerous Connections!
Tonearm with Attached Balanced Cable
Tonearm with 5-Pin Tiffany Jack
Turntable / Tonearm with RCA Jack
Turntable / Tonearm with XLR Jack
Settings Inside Phono MCCI
Detailed Jumper Settings
Troubleshooting, Maintainance, Service
Important Safety Information
General Safety Precautions
CE / FCC declaration, Recycling
Technical Specifications
Quick Start
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B.M.C.AUDIO GmbH
WWW.BMC‐AUDIO.COM INFO@BMC‐AUDIO.COM
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Introduction
Thank you for purchasing this exceptional MC phono preamplier!Also thanks for supporting an
important step for the phono reproduction quality:The need of balanced operation for overcoming
traditional limitations in musical performance!Since phono cartridges by their nature are truly an earth‐
free signal source,balanced operation has obvious advantages which are known since longer time,but
so far balanced operation got rarely applied due to old conventions from the mass‐market.
The balanced "Current Injection"input truly sets new standards for the amplification of MC cartridge
signals.For the first time a balanced "Current Injection"circuitry has been developed specifically for the
purpose of use with MC cartridges.The outstanding signal‐to‐noise ratio allows the match with very low
output cartridges without the need of a transformer.
Due to the mandatory earth‐free operation mode there could be some incompatibilities with unbalanced
interconnections.
Take care of a truly earth‐free interconnection as described within this manual.You may ask your
retailer for help in case of any question.
Due to the very low‐noise current input of the PHONO MCCI the selection criteria for a moving coil
cartridge could be re‐evaluated,as the need for having a resonable voltage level is not that important
anymore.Low impedance is important for signal strength as well.
High‐Output MC cartridges always have multi‐layer‐coils and since with every coild layer the
geometrical precistion degrades,the performance might be affected.
Please have a look at "Cartridge Selection" (page 6).
Content of Packing
PHONO MCCI unit
AC Power Cable
Owner's Manual
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Front Panel Functions
POWER
Power on the units by turning right the wheel.
Power off the unit by turning left the wheel.
DIM
Reduce the illumination intensity.
MUTE
Press the knob for muting the output.
This function is recommended when using the tonearm lift.
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Rear Functions
INPUT XLR
Current‐Injection MC Phono‐Input
Terminal for an earth‐free balanced connection from a turntable with moving coil cartridge.
The signal lines must be exclusively connected to XLR Pin2 (+=Hot)and Pin 3 (‐=Cold). An
independend shield can be connected to Pin 1as well as the turntable chassis and the tonearm.
The shield must NOT be connected to any of the four signal lines.
OUTPUT XLR /RCA
Balanced (XLR) / unbalanced (RCA)Output
Balanced and unbalanced line level output terminals for connection to the B.M.C.DAC preamp module,
an integrated amplifier or a preamplifier.
XLR interconnection should always be the preference!
AC‐LINE
AC Line Terminal
For connecting the AC power line using the included power cable.
Please make sure your local AC line voltage matches to the voltage printed on the rear panel of the unit.
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Cartridge Selection
The selection for best performing moving‐coil cartridges changes if,instead of a conventional voltage
amplifier input,a current‐injection input proceeds the signal.
One difference is the much higher electro‐magnetic damping of the CI input,controlling cartridges with
less mechanical damping.Simultaneously,the outstanding electro‐magnetic damping of the cartridge is
not at the expense of dynamics ‐on the contrary:The current withdrawn from the Moving Coil is used
as the original music signal.
The output voltage of a pickup is not the only criteria for the expected volume and dynamics.Only in
correlation with the internal impedance of a Moving Coil,the corresponding current can be calculated.
Although due to different measurement methods,not perfectly comparable values,but a trend can be
clearly seen,as long as both electrical parameters are available:The output voltage of a pickup as well
as its internal resistance.
Based on Ohm's law the signal current can be calculated:
V: (Rmc +Rin) = I
V=defined output voltage
Rmc =internal resistance of the MC cartridge
Rin =input resistance of the phono amplifier
I=signal current
On the low side some MCs deliver 10μA or less,under CI‐Input conditions.
A wide middle range of cartridges deliver between 10 and 30μA.
High efficient Moving Coils exceed 30μA,some models deliver up to 100μA.
Extremely high efficient Moving Coils may need individual gain settings inside of BMC PHONO MCCI,
which is an easy job for any authorised BMC Service.
Phono amplifiers with current input stage are still rare,therefore some MC manufacturers didn't consider
the MC's efficiency so much.Nevertheless in recent years several brands did increased efforts of
improving their cartridge's efficiancy,due to significant quality improvement.
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The coaxial connection is a questionable compromise which might be useful for testing.An already
present RCA connection can just be connected to XLR plugs.This is not a balanced connection indeed
and this you may expect some noise interference.Concering sound quality we do not recommend this
solution either.
The best way to connect is a balanced "twisted pair"cable with additional shielding.The cartridge can
be dirctly connected to the balanced input this way and the shield is connected just one‐sided and
eventually to the turntable chassis.No cardridge pin is allowed to be shorted to the tonearm or chassis!
With this connection you can enjoy exellent sound quality results.
A balanced connection without any shielding might sound best as long as you don't experience any
noise by interferences.Twisted cables are mandatory for this type of connection!The CI‐input is not
very sensitive to capacitive noise and also has a high rejection of common‐mode noise.The cable
should generally be low‐inductive for CI‐connections.In case of any trouble you better use the above
suggestion.
In case of making a testing adaptor from RCA to XLR following point
should be considered:
1. The adaptor must be connected according to the above drawing.Pin
1of the XLR Plug must remain unnused!
2. None of the RCA grounds is allowed to be connected to the tonearm or chassis.
Better check the above suggestion by a multi‐meter for short circuits.
As this is indeed not a clean balanced interconnection you may expect some noise as well as reduced
sound quality.Such adaptor should be just a short‐term solution.
Any unbalanced cable at the Phono MCCI input is a waste of sound quality!
NEVER plug any cable while the unit is powered on!
Balanced Phono Interconnection
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Caution: Dangerous Connections
Wrong wiring from the turntable and Phono MCCI may lead to damages!
The magenta coloured dotted lines on the above drawings show the dangerous wiring that must be
avoided in any case.
∙Never connect pin 1and 3from the XLR input connector.
∙Never connect pin 1and 2from the XLR connector.
∙Never connect any of the four signal lines to pin 1.
∙Whenever using a coaxial interconnection take care the shields are never connected to the
turntable chassis or the tonearm.
∙Whenever using a coaxial interconnection take care the shields from left and right channel
are never connected to each other.
∙Cartridges with common ground do not match for the use with Phono MCCI
∙In case of question please consult your retailer
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Tonearm with Attached Balanced Cable
The attached direct wiring is generally the best interconnection with the least contact transitions.An
optimum sound quality requires an excellent sounding interconnection.
Coaxial cables are not balanced at all.They are sensitive to hum and RF interference and sound
inappropriate.An optimum musical experience requires the usa of balanced interconnections.
Twin cables per channel are fine,twisted or interwoven cables are best.
Shielding is not always required,but recommended in a turbulent electromagnetic environment.Without
shielding a more open sound may arise.
In many cases an existing internally balanced tonearmcable with
RCA connectors can be easily converted to balanced circuit with
XLR connectors according to the pattern shown here.
The shield should be connected only to pin 1, if there is not any
connection to any of the inner conductors.
Warning:Rega tonearms with no separate ground cables usually have a connection between the
tonearm mass and the blue wire of the left channel.This connection must be strictly separated by a
professional!
Thorens TP16 tone arms have a connection from the green cable to the headshell.This must be
removed from the pin to the head shell and isolated.The green wire in the headshell should be
connected exclusively to the Right Minus contact of the pickup.
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Tonearm with 5-Pin Tiffany Jack
For the 5‐Pin Tiffany to XLR connection is to be noted particularly that the tonearm ground is connected
from the middle pin of the Tiffany‐plug only to ONE channel XLR pin 1, otherwise risking hum noise due
to a ground loop.
The shield (if any)should however be separately connected to pin 1of the XLR connector for each
channel.
Indice
