Schoeps VMS 5 U Microphone preamplifier with M/S matrix, incl. batteries

Schoeps VMS 5 U Microphone preamplifier with M/S matrix, incl. batteries

Battery-operated microphone preamplifiers sometimes have high noise figures because current consumption is kept limited in the interests of longer battery life. But the VMS 5 U places hardly any such limitation on the performance of the microphones. In addition, its frequency response leaves nothing to be desired.

with switchable phantom powering and M/S matrix
frequency response: 20 Hz – 80 kHz (-3 dB)
two low-cut filters: 20 Hz (permanent) and 150 Hz (switchable)
inputs: XLR-3F (balanced) and special socket for Active Y-Cable of the Colette modular system
outputs: XLR-3M (balanced); easy connection to unbalanced inputs without loss of signal level
headphone monitor output
gold-plated sockets and switch contacts for long service life
glitch-free, automatic switchover to internal batteries in the event of AC power loss
runs on six internal batteries (included) or external DC supply (accessory)
automatic shutoff if voltage gets too low
gold-plated sockets and switch contacts for long service life
black all-metal housing (aluminum)

Overview

One of the characteristics of high-quality equipment is durability. It may be several years before you find out whether the potentiometers and switches on a unit will become noisy when used. In the design of this product, SCHOEPS placed the primary emphasis on reliability and durability, choosing all its components (such as switches and sockets with gold-plated contacts) accordingly.

A special version (VMS 5 U lin.) without the fixed 20 Hz low-cut filter is available for measurement applications.
This version is not recommended for audio applications because of the possibility of infrasonic noise problems.

Application

Specifications

VMS 5 U
Frequency response	20 Hz – 80 kHz (-3 dB)
Input impedance	20 kΩ
Input	switchable between two XLR-3F sockets and a special input for the SCHOEPS KCY Active Cable
Input	recommended minimum sensitivity of microphones at XLR inputs: 8 mV/Pa
Maximum input level for 0.5% THD	at 4 dB gain setting: 14 dBV (5 Vrms) at 20 dB gain setting: -2.2 dBV (780 mVrms)
Preamplifier gain	can be set to 4, 10, 20, 30 or 40 dB
Maximum sound pressure level at 0.5% THD	with CMC 6 and MK 4 (cardioid) at a gain of 4 dB: 132 dB at 10 dB: 132 dB at 20 dB: 130 dB at 30 dB: 120 dB at 40 dB: 109 dB
Equivalent noise level	at a gain of 4 dB: 16.5 dB-A at 10 dB: 16 dB-A at 20 dB: 15.5 dB-A at 30 dB: 15.5 dB-A at 40 dB: 15.5 dB-A
Equivalent noise level (CCIR)	at a gain of 4 dB: 27.5 dB-CCIR at 10 dB: 26.5 dB-CCIR at 20 dB: 26 dB-CCIR at 30 dB: 26 dB-CCIR at 40 dB: 25.5dB-CCIR
Level indicators	-20 dB, -3 dB
Additional comments	The BALANCE potentiometer permits compensation for differences in microphone sensitivity up to 20 dB.
Additional comments	The polarity inversion switch permits rapid change of input channel assignments in M/S recording, as when changing between an upright stereo microphone and one that is hanging downwards.
Output	The outputs are impedance-balanced and transformerless, and are switchable between the amplified microphone signals and the decoded M/S stereo signals.
Output impedance	100 Ω
Maximum output level for 0.5% THD	18 dBV (8 Veff)
Minimum recommended load impedance	2kΩ
Headphone output	Switchable; either the amplified microphone signals (=left / right for A/B recordings, or mid / side for M/S) or the decoded M/S stereo signals can be monitored.
Output impedance	32 – 2,000 Ω
Output socket	1/4'' stereo phone jack
Filter(s)	An infrasonic filter (20 Hz, 18 dB/oct.) is permanently active. In addition, a low-cut filter (150 Hz, 6 dB/oct.) can be switched on. The upper frequency limit is 80 kHz.
Powering	An internal filter / regulator circuit which generates and stabilizes the supply voltages permits a wide range of input voltages (5.5 V to 15.5 V).
Battery powering	Operation with internal batteries (possibly rechargeable) Number and type of cells: 6 × AA (also called LR6) Recommended primary cell type: Alkaline Recommended rechargeable cell type: NiMH A user-replaceable fuse protects against reversing the polarity of the batteries. Battery life with alkaline cells: ca. 8.5 hours Battery life with rechargeable batteries: ca. 3 hours (700 mAh NiCd) ca. 5 hours (1100 mAh NiMH) ca. 5.5 hours (1300 mAh NiMH) ca. 7 hours (1600 mAh NiMH) ca. 12 hours (3400 mAh gelled lead-acid battery (external)) A voltage indicator displays the battery voltage within the unit. A warning LED will begin to blink if the voltage falls beneath a critical value (time remaining at that point with 1300 mAh rechargeable batteries: at least 10 minutes). The unit will shut itself off automatically to help prevent damage from draining the batteries completely. The unit resumes operation only after the on / off switch is used.
External powering	An appropriate AC power adapter is available (model VMS DC). Other adapters or external batteries can also be used. They should have at least 6V, we recommend 12V. An open-circuit voltage of 16 V must not be exceeded. 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, the internal batteries are automatically disconnected (indicated by yellow LED “EXT.”). This protects the batteries from being charged or discharged unintentionally. The battery voltage indicator displays the level of an external powering. Parallel operation of a VMS 5 U along with other equipment from a single power supply is possible.
Dimensions	Overall measurements: (W × H × D): approximately 6-2/3'' × 2-1/3'' × 6-3/4'' which corresponds to 162 × 60 × 172 mm
Weight	with batteries: approximately 2 lb. 7 oz. which corresponds to 1.1 kg