VMS 5 U & VSR 5 U

  • 48V phantom power
  • Also for Schoeps' active "Y" cable
  • Switchable, variable M-S matrix
  • Switchable phones output (before or after M-S matrix)
  • Operates on internal batteries or an external AC adapter
  • Specially designed power management system with protection against leakage due to deep-draining of batteries
  • High-quality, long-life switches and sockets (gold-plated contacts)
  • Robust aluminium housing (W x H x D: 169 mm x 60 mm x 163 mm)
  • A compact M-S microphone assembly is available, with windscreen (WSR MS)

The VMS 5 U is a high-quality microphone preamplifier with phantom powering, a M-S matrix and a switchable headphone output, all in a robust metal case. It permits the use of normal microphones such as the Schoeps CMC series, as well as the Schoeps active "Y"-cable with Colette microphone capsules. The VMS 5 U can be powered by internal or external batteries (including rechargeable types) or an external AC adapter. It can readily be powered along with other units from a common supply. Switches and sockets are of high quality (e.g., gold-plated contacts), thus ensuring long, trouble-free operation.

Switchable between two XLR-3F sockets and a special 5-pin Binder input for the Schoeps KCY active "Y" cable. XLR inputs are balanced and transformerless; the 48-Volt phantom powering can be switched off (for subsequent post-production M-S dematrixing).
Input impedance: 20 kOhm
Recommended minimum sensitivity of microphones at XLR inputs: 8 mV/Pa
Maximum input level (20 dB gain setting) for < 0.5% THD: -2.2 dBV (780 mV rms)
Preamplifier gain settings: 4, 10, 20, 30 or 40 dB
Performance specifications of VMS 5 U with Schoeps CMC 64 (cardioid):  
Equivalent noise level: 17 dB (A-weighted), 27 dB (CCIR, qps)
Maximum sound pressure level:
        at 4 or 10 dB gain:
        at 20 dB gain:
        at 30 dB gain:
        at 40 dB gain:
132 dB, limited by microphone
130 dB
120 dB
109 dB
Peak level indicators: -20 dB, -3 dB
The "Balance" potentiometer permits compensation for differences in microphone sensitivity. A polarity inversion switch permits the rapid exchange of L-R channel assignments in M-S recording.
The outputs are balanced and transformerless, and are switchable between the amplified microphone signals and the decoded M-S stereo signals.
Output impedance: 100 Ohms
Maximum output level for 0.5% THD: 17 dBV (7 Vrms)
Recommended load impedance: 2 kOhm or greater
Switchable; for monitoring either the amplified microphone signals ("PREAMP" = left/right for A/B or X/Y recordings) or ("MATRIX" = mid/side decoding for M-S stereo inputs).
Headphone impedance: 32 - 2,000 Ohms
Headphone socket: 1/4" stereo phone jack
An infrasonic filter (20 Hz, 18 dB/oct.) is permanently active. In addition, a low-frequency rolloff (150 Hz, 6 dB/oct.) can be switched in.
An internal filter/regulator circuit permits a wide range of input voltages.
OPERATION WITH INTERNAL BATTERIES (including rechargeable types):
Number and type of cells: 6x AA
Recommended battery type: Alkaline
Recommended rechargeable type: NiMH
A user-replaceable fuse protects against accidentally 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. 5.5 hours (1300 mAh NiMH)
A voltage indicator displays the battery voltage during operation. A warning LED will begin to blink if the voltage falls below a critical value (time remaining at that point: at least 10 minutes with rechargeable batteries). The unit will shut itself off automatically to help prevent damage resulting from completely draining the batteries. With rechargeable batteries, this reduces the risk of any individual cells inverting their polarity. The unit can be brought back into operation by turning the "Power" switch off and on again.
Coaxial socket, 5.5 mm x 2.1 mm
Reverse polarity will not damage the unit, athough it will not operate. If external powering is present, the batteries are automatically disconnected (indicated by yellow LED "EXT."). This protects the batteries from being drained or loaded unintentionally. The battery voltage indicator displays the level of any external powering.
The unit can be operated with an unfiltered DC voltage from 6 V (500 mA) up to 15 V (250 mA) at the external supply input socket or 10-13 VAC.
Parallel operation for a VMS 5 U from a single power supply, along with one or more other pieces of equipment, is generally possible because of the internal galvanic isolation by the regulator. The design of the rear panel is deliberately labeled "upside down" to allow the unit to be connected or disconnected without turning it around while in use.
Robust, black metal case; designed for portable use.
Dimensions: W x H x D: 169 mm x 60 mm x 172 mm
(approximately 6-5/8" x 2-3/8" x 6-3/4")
Weight: 1.2 kg (approximately 2 lb 10 oz)
Price: VMS 5 U $2,402.00

Analog Reference Microphone Preamplifier – low noise and distortion, RF protected

SCHOEPS now introduces the VSR 5, a top-class studio microphone preamplifier. It excels with its wide dynamic range, extremely low distortion, and comprehensive protection from radio frequency interference.

The VSR 5 is SCHOEPS’ first 19" rackmount unit, conceived specifically for use in the studio. For a number of years its circuit has been our in-house reference for testing microphones, so it seemed only logical to make it available to our customers as well.

Amplifier modules

Two amplifier modules (Core SVM) form the heart of the VSR 5. They were inspired by the legendary ”TransAmp LZ” modules from Valley People, long recognized for being especially low-noise.

RF Filters

Professional audio equipment today must be adequately protected from electromagnetic inter ference emanating from cell phones and other mobile communication devices with frequencies up to 2 GHz and higher, as well as radio and TV transmitters. The VSR 5 shows that this protection need not come at the expense of excellent audio quality. The extensive RF filtering does not limit the preamplifier's bandwidth, its common-mode rejection or its freedom from distortion. This is possible because of the use of special, modern circuit components and a well-thought-out circuit design.

High-quality components

The operating controls of the VSR 5 have been deliberately limited to essentials:

  • a highly precise, repeatable rotary gain control ranging
    from 0 to 60 dB in 3 dB steps
  • a wide-range, fast-responding array of LED level indicators covering -48 dBr through +9 dBr, with a ”Clip” LED at +20 dBr
  • switchable phantom powering. The VSR 5 recognizes
    automatically when a condenser microphone has been
    connected; the LED of the "P48" switch glows yellow
    when powering is enabled and green when a condenser
    microphone is connected.
  • a polarity reversal switch
  • a ”Mute” switch. Muting occurs automatically during turn-on and turn-off of the preamp, and also of the phantom
    powering circuit.
  • a switchable second-order low-cut filter for suppressing pop and wind noise or infrasonic disturbances. The cutoff
    frequency can be set to 40, 80 or 120 Hz so as to remove
    as little as possible from the desired signal.
  • two separate, independent low-impedance, active balanced (symmetrical) floating outputs per channel

The VSR 5 is distinguished by the high quality of its components. In particular:

  • an especially low-noise, low-distortion gain module with superior common-mode rejection
  • high-quality filters that protect both the inputs and outputs from radio-frequency interference without any adverse effect on the sound quality
  • a high-quality rotary gain control with repeatable settings in 3 dB steps
  • a robust stainless-steel housing that shields the circuitry from external interference
  • gold-plated contacts on the XLR connectors and the rotary gain control for long-life, noise-free operation

* according to IEC 61938
** common-mode rejection ratio
*** according to IEC 61672-1
****according to IEC 60268-1

Inputs: 2, electronically balanced and floating
Phantom powering: +48 VDC (P 48*); can be switched off
Resistances: 2 × 6.85 kOhms
Maximum current: 10 mA (according to standards)
Minimum current at which LEDs indicate a microphone at an input: 1.7 mA
Input impedance: 8 kOhms
Input CMRR** at 60 dB gain: > 90 dB at 1 kHz (for typical values see Fig. 1) / > 80 dB at 15 kHz
Max. input level: 25.4 dBu (23.2 dBV) at 0 dB gain, f = 1 kHz
Gain adjustment: 0 dB ... 60 dB in steps of 3 dB
Gain accuracy: ±0.3 dB
Low cut filters (-3 dB): 40 Hz, 80 Hz, 120 Hz at 12 dB/oct. or ”off” (see Fig. 2)
THD+N at 1 kHz: 0.0006% at 30 dB gain and 27.5 dBu output level (1 dB below clipping) into 100 kOhm load (see Fig. 3)
Noise (input terminated with 200 Ohms; gain: 60 dB, referred to input): -127.8 dBu (-130.0 dBV), unweighted, RMS -130.6 dBu (-132.8 dBV), A, RMS*** -117.4 dBu (-119.6 dBV), CCIR-1k, Q-peak****
Frequency range (gain: 30 dB): 12 Hz ... 90 kHz (±0.1 dB) / 2.5 Hz ... 400 kHz (-3 dB)
Inter-channel phase difference: 0.0° at 5 Hz / 0.0° at 50 Hz / 0.0° at 1 kHz / 0.0° at 10 kHz / +0.20° at 200 kHz
Slew rate of the ”Core SVM”: 10 V/µs at 30 dB gain
RF filter range (in- and outputs): 3 MHz – 1 GHz, see Fig. 4
Max. output level: 28.5 dBu (26.3 dBV)
Max. output level: 28.5 dBu (26.3 dBV)
Output impedance: 50 Ohms
Output CMRR*: ca. 60 dB (20 Hz – 20 kHz)
Meter range: -48 dBr ... +9 dBr (adjustable) / clipping LED lights up at +15 dBr
Power supply: 94 ... 125 VAC / 185 ... 250 VAC, 50 – 60 Hz
Power consumption: 10 VA
Dimensions (19", 2U): 485 mm (w) × 60 mm (h) × 195 mm (d)
Weight: 4.70 kg, 10.34 lbs
Case: stainless steel, aluminum
Front: gray Nextel finish; front panels: stainless steel
Two "Schoeps Core SVM" Amplifier Modules with balanced, electronically floating Inputs, +48 VDC phantom power (switchable), 0 to 60 dB rotary gain controls in 3 db steps, State-of-the-Art RF Filters, 2 x 2 electronically floating balanced outputs, Mains Supply 115/230 VAC, 19" Rackmount - 2U, 10.34 lbs.


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Most recent revision February 20, 2014