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7

0.5 A fast-blow fuse will burn out. It is
accessible through the battery com-
partment; a spare fuse is provided
within the unit. The locations of both
the actual and the spare fuse are shown
in the drawing on the inside of the bat-
tery compartment lid. A pair of regular
pliers (not "needle-nose") can be used
to facilitate changing the fuse.

By maintaining separate grounds for

audio signals and for powering, the
supply regulation circuitry of the 
VMS 5 U permits the sharing of a com-
mon power source with other equip-
ment, without the risk of ground loops.

Notes on operation with an AC
power supply

Any AC power supply that will deliver

at least 7 V at 500 mA in actual use
and an open-circuit voltage of no more
than 16 V will be suitable. For exam-
ple, the SCHOEPS AC power supply
VMS 5 DC (input = 230 VAC, equipped
with "Euro plug") delivers a stabilized
12 Volts DC.

Please note:

Different countries use

different AC voltages. Always make
sure that your power supply is appro-
priate for the AC voltage where you are.

Notes on operation with exter-
nal batteries

The batteries should have a nominal

voltage of 6 to 12 Volts and a capacity
of at least 500 mAh. A 6-Volt set of
gelled lead-acid rechargeable batteries

Note the polarity of the DC power

connector: the positive pole of the
power supply must be connected to
the center contact of the external
powering socket (<18> on page 3).
The unit will not be harmed by reverse
polarity, but will not operate; a protec-
tive diode will prevent current from
flowing.

If a sufficient external DC voltage is

connected to the external powering
socket of the unit, the "EXT" LED (<13>
on page 3) will light, even if the unit is
turned off; it is strictly an indication of
available powering, not of the unit’s
on/off status. In this mode of opera-
tion, any batteries inside the unit will
neither be charged nor discharged.

If for any reason the external power-

ing should drop below the minimum
required voltage (e.g. loss or reduction
of AC power), the unit will immediately
switch over to battery power, assum-
ing of course that batteries of sufficient
voltage are in the unit; the yellow LED
will then go out. This automatic switch-
over will occur without any disturbance
in the audio signal.

The “LOW BAT” LED <13> will blink

when the input voltage is less than or
equal to about 7.5 Volts, but this can
be ignored unless the battery indicator
is at the low end of the red region.

The meter is calibrated with reference

to internal batteries and will “under-read”
slightly with external power sources.

If too high a voltage is applied to the

external powering socket, the internal

Содержание VMS 5 U

Страница 1: ...VMS 5 U User s Manual Microphone preamplifier with phantom powering M S matrix and headphone output with special input for Schoeps active Y cable...

Страница 2: ...ts 18 Input for external power supply 19 Input selector switch The connectors and labels on the rear of the VMS 5 U are upside down with respect to the front of the unit This simplifies its use since...

Страница 3: ...3 15 16 19 17 18 8 9 10 11 12 13 14 1 2 3 6 7 4 5...

Страница 4: ...tweight robust all metal housing 1 Inserting batteries The VMS 5 U operates from six AA LR 6 cells included Primary cells preferably alkaline can be used or rechargeables such as NiCd or NiMH To inser...

Страница 5: ...echarge ables should all be of the same type and capacity as one another all batter ies should be changed and or charged together as a set This is to avoid the risk of one or more cells those of lower...

Страница 6: ...neath the limit of proper functioning This avoids overly deep discharge of the batteries which could otherwise lead to chemical leakage or in the case of rechargeable batteries life shortening damage...

Страница 7: ...ble batteries Note the polarity of the DC power connector the positive pole of the power supply must be connected to the center contact of the external powering socket 18 on page 3 The unit will not b...

Страница 8: ...your headphones temporarily 8 Connecting 48 Volt phantom pow ered studio condenser microphones For the highest quality lowest noise recordings use condenser microphones with a sensitivity of at least...

Страница 9: ...ed only when needed since it has a distinctly audible effect position Now you can turn the unit on For ordinary stereo recordings not M S the cable marked in red should carry the right channel signal...

Страница 10: ...ible rejection of hum and radio frequency interference Not all recorders offer balanced inputs but with short cables less than a few meters this is generally not so critical If you need to connect the...

Страница 11: ...cording techniques A B X Y ORTF Blumlein etc two micro phones are used of which one the side or S channel must have a figure 8 directional pattern the other microphone the mid or M chan nel may have a...

Страница 12: ...ll become narrower Any sound sources located beyond that angle near the edges will be picked up out of phase and will seem to jump over to the channel opposite from where they were in reality The opti...

Страница 13: ...eard in a steadily decreasing degree in the left channel output signal But if that sound source crosses past the null in the polar diagram of the left channel virtual microphone see above its presence...

Страница 14: ...1 M MK4 CCM 4 Effect of the WIDTH control on the recording angle for various types of M channel microphones Effect of the WIDTH control on the gain applied to M and S signals S M M M S S 0 1 2 3 4 5 6...

Страница 15: ...find an optimal setting for the stereo image width as it would be reproduced through loudspeakers In addition to experimenting with various width settings it can some times be very useful to equalize...

Страница 16: ...alanced trans formerless and are switchable between the amplified microphone signals and the decoded M S stereo signals Output impedance 100 Ohm Maximum output level for 0 5 THD 18 dBV 8 Vrms Recommen...

Страница 17: ...ll blow See page 7 Coaxial socket 5 5 2 1 mm diameter Reverse polarity will not damage the unit though it will not operate If external powering is present any internal bat teries are automatically dis...

Страница 18: ...18 16 Block diagram...

Страница 19: ...19 Frequency response curves above without low cut filter below with low cut filter...

Страница 20: ...0 C to 50 C The headphone volume levels which can be achieved with this unit can with prolonged use cause lasting damage to one s hearing Please monitor only at the minimum necessary levels Cables Use...

Страница 21: ...to misuse e g incorrect operation mechanical damage abuse or acts of God This guarantee is nullified in the event of tampering by unauthorized persons or agencies To secure your rights under this guar...

Страница 22: ...22...

Страница 23: ...23...

Страница 24: ...24 Subject to change without notice 010102...

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