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VMQ-4 User Guide Introduction Overview The single-rack space VMQ-4 permits simultaneous monitoring of up to four audio sources with “voice quality” fidelity. Because each channel has its own dedicated power amplifier and speaker, the audio sources remain completely separate from analog input to output. When listening within “Ultra Near Field” distances of 1 to 3 feet, these discrete speaker outputs provide enhanced source distinction when compared to designs with four inputs mixed into a single output.
VMQ-4 User Guide S a f e t y I n s tr u c ti o n s Safety Instructions IMPORTANT: 1. Read, keep, and follow all of these instructions; heed all warnings. 2. Do not use this equipment near water or moisture. 3. Use only a dry cloth to clean the equipment. 4. Do not block any ventilation openings. Install only in accordance with the instructions in the section entitled, “Installation Recommendations” on page 6. 5.
VMQ-4 User Guide I n s ta l la t i o n R e c o m me n d a t io n s Installation Recommendations Mounting The unit is designed to install into a standard 19" rack mounted at eye level for best visual observation of the monitor screens. Heat Dissipation Heat dissipated by the speaker amps is conducted directly to the sides of the chassis; no special considerations for cooling are necessary as long as the ambient temperature inside the rack area does not exceed approximately 40°C (104°F).
VMQ-4 User Guide I n s t a ll a t io n R e c o m m e n d a t i o n s Electrical Interference As with any audio equipment, maximum immunity from electrical interference requires the use of shielded cable; however, satisfactory results can sometimes be obtained without it. The internal circuitry common is connected to the chassis. In the VMQ-4 (standard analog inputs), unbalanced sources may also be applied to the balanced inputs.
VMQ-4 User Guide Applications Audio Connections Connection of the audio feeds is straightforward. The system block diagram inFigure 1–3 on page 9 may be referred to for clarification of the general signal paths into and out of the VMQ units. Please note that the internal circuitry common is connected to the chassis. The gain is approximately 4dB greater with a single-ended source connected across both "hot" terminals than when connected between either input and common.
VMQ-4 User Guide S p e c if i c a ti o n s • Fully magnetically shielded. • Signal present LED on each channel output. • Mute button and LED for each channel. • Headphone jack Specifications Table 1–1 VMQ-4 Specifications Specification Input impedance Value >100 k balanced >50 k unbalanced 0 dBv balanced.
VMQ-4 User Guide Front Panel Controls Front Panel Controls Figure 1–1 Volume VMQ-4 Front Panel Headphones Power Mute/Chanel Activity • Internal Speakers: The VMQ internal speaker system is comprised of four separate mid-range speakers. From left to right the speakers correspond to channels 1 through 4; one speaker for each of the four channels.
VMQ-4 User Guide R e a r P a n e l C o n n e ct o r s • Channel Activity Indicator: Signal activity in any given channel will cause the LED in the associated button for that channel to glow amber. • Power Indication (Green LED): The Power Indicator LED signals the operating condition of the power supply. The LED glows green to indicate the VMQ-4 is connected to mains power and an operation voltage is present. Rear Panel Connectors HI LO VMQ-4 253881-01 MONTH 1 YEAR Power HI LO www.Wohler.
VMQ-4 User Guide T e c h n i c a l F u n c t i o n a l O v e r vi e w Technical Functional Overview Figure 1–3 below illustrates the overall functionality of the VMQ-4. Figure 1–3 VMQ-4 Block Diagram Mute 1 Amplifier 1 1 Mute 2 Mute 3 Left HP SUM Speaker 2 Volume 3 Headphone Amplifier 3 3 Mute 4 4 Volume 2 Speaker 1 Amplifier 2 2 Analog Inputs Volume 1 Volume 4 Amplifier 4 Speaker 3 Right HP SUM Speaker 4 © 2 01 0 Wo h le r Te ch n o l og ie s, I n c .