MX821S
Eight Channel Mic/Line Mixer with Stereo Outputs
User's Manual
Brand: Applied Research and Technology (ART)
Important Safety Instructions
Retain these safety and operating instructions for future reference. Heed all warnings printed here and on the equipment. Follow the operating instructions printed in this user guide.
General Precautions
- Do not open: Contains no user-serviceable parts. Refer service to qualified personnel.
- Power Sources: Connect only to mains power matching the description on the unit and ensure a good ground connection.
- Power Cord: Use the provided cord. Route it to avoid damage.
- Grounding: Do not defeat grounding or polarization means.
- Moisture: Do not expose to rain, moisture, or damp conditions. Do not place liquids on the unit.
- Heat: Avoid locating near heat sources or direct sunlight.
- Environment: Protect from excessive dirt, dust, heat, and vibration. Avoid tobacco ash, spills, and smoke.
- Handling: Protect controls during transit. Use padding. Exercise care when lifting or moving.
- Servicing: Unplug immediately if exposed to moisture, spills, damaged cord/plug, or if smoke/odor/noise is noted. Refer servicing to qualified personnel.
- Installation: Install according to user guide instructions.
Symbol Explanations:
- ⚠ [Warning Symbol]: Alerts to uninsulated dangerous voltages inside, posing a risk of electric shock. (French: ATTENTION: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR)
- ☑ [Caution Symbol]: Alerts to important operating and maintenance instructions in the accompanying literature. Please read the manual.
Introduction
The ART MX821S is a versatile rack-mount mixer that combines eight independent input channels into a stereo line-level output. Each channel accepts a balanced XLR microphone input or an unbalanced 1/4-inch TS line-level signal, offering independent level and pan controls. +48 Volt phantom power is switchable per microphone input. A master level control manages the signal output to the balanced 1/4-inch TRS main outputs. Prefade output and Aux Bus input RCA jacks facilitate chaining multiple units for expanded channel capacity.
The MX821S is suitable for stage, studio, and permanent installations such as conference rooms, corporate boardrooms, churches, restaurants, small clubs, and health clubs. Its built-in power supply and single 1U, 19-inch rack-mount format ensure easy installation and reliable operation.
Features:
- Eight input channels with individual level and pan controls.
- Pan controls allow precise placement of each input's mono signal within the stereo image.
- Balanced XLR microphone inputs and unbalanced 1/4-inch TS line inputs on each channel.
- Switchable +48V low-noise phantom power for each microphone input.
- Balanced 1/4-inch TRS main output jacks (Left and Right) with master level control.
- Prefade Output jacks and Aux Bus Input jacks for chaining units.
- Internal jumpers allow conversion of each line input jack to a direct line output.
- Rugged 1U rack-mount steel chassis with integrated power supply.
- Ideal for stage, studio, and permanent installations.
- Includes a three-year warranty.
Connections
Rear Panel Connections
The rear panel features:
- Mono CHANNEL Inputs (1-8): Eight female XLR connectors for balanced microphone signals. Provide an additional 26 dB of gain for low-output mics. +48V phantom power is available via switches for condenser microphones.
- LINE Inputs (1-8): Eight 1/4-inch jacks for unbalanced line-level signals. Use shielded cables with 1/4-inch TS plugs.
- AUX BUS IN: RCA jacks for patching signals.
- PREFADE OUT: RCA jacks for pre-fade outputs.
- MAIN OUTPUTS (BALANCED): 1/4-inch TRS jacks for balanced stereo line-level outputs.
- AC INPUT: Standard AC power connection.
- FUSE: 250V, T 0.5A fuse.
LINE Input to Direct Line Output Conversion:
To convert a 1/4-inch line input to a direct line output for that channel: disconnect AC power, remove the top cover. Locate the internal jumpers. Move the jumper for the desired channel to the left (when viewed from the front). This converts the line input to a direct line output, which can be connected to another mixer's input. The MIC input signal for that channel remains available in the main output mix. Caution: Do not connect a mixer output or other signal source to the 1/4-inch jack on a converted channel, as this may cause damage. Ensure the lid is replaced before reconnecting AC power.
Both MIC and LINE inputs accept mono signals that can be routed to the left or right channels, or a combination, using the front panel PAN control.
Operation
Front Panel Controls
- POWER Switch: Controls AC power. Pushed in (ON position) activates the unit, indicated by a green POWER LED.
- MASTER LEVEL Control: Adjusts the overall output level for the MAIN OUTPUTS (Left and Right).
- CHANNEL Controls (1-8) LEVEL: Adjusts the level of each input channel and its contribution to the overall mix. Turn unused input levels to 0 (fully counterclockwise) to minimize noise. For best noise performance and minimal distortion, set channel levels high (towards 10) and adjust the MASTER LEVEL control down as needed.
- PAN Controls (1-8): Adjusts the stereo panorama position of each input channel. Fully counterclockwise is Left, fully clockwise is Right.
Rear Panel Controls
- +48V PHANTOM POWER Switches (1-8): Numbered switches for applying phantom power to corresponding rear-panel MIC XLR connectors. UP is OFF (no phantom power). DOWN is ON (applies phantom voltage). Current is limited to 7 mA per leg. Do not apply phantom power to microphones not designed for it.
Block Diagram
The block diagram illustrates the signal flow. Input signals (MIC - balanced XLR, LINE - unbalanced 1/4-inch TS) enter eight input channels. Each channel has LEVEL and PAN controls. +48V PHANTOM POWER can be applied to the MIC inputs. Signals are routed through a BUS to the MASTER LEVEL control, which affects the MAIN OUTPUTS (Left and Right - balanced 1/4-inch TRS). PREFADE OUT (RCA) and AUX BUS IN (RCA) are also shown for signal routing and expansion.
Warranty Information
Limited Warranty (USA only)
Applied Research and Technology (ART) warrants this product and its components to be free from defects in workmanship and materials for a period of three years from the date of purchase for the original purchaser. ART will, at its option, repair or replace defective units or parts free of charge upon prepaid delivery to the factory service department or an authorized service center, accompanied by proof of purchase (sales receipt).
Online Registration
Register your product online at www.artproaudio.com under "Support" > "Product Registration" for prompt warranty service.
Exclusions
- Warranty does not apply to misuse, abuse, or unauthorized alterations/repairs.
- Warranty is void if the serial number is altered or removed.
- ART reserves the right to make design changes without obligation to apply them to previously manufactured products.
- ART is not liable for consequential damages, including loss of use. State laws may vary regarding limitations on incidental or consequential damages.
For units purchased outside the United States, service is provided by an authorized ART distributor.
Service
If your unit requires service:
- Verify the unit is the cause of the problem. Check power, cables, and connections. Consult your dealer for assistance.
- If the ART unit is at fault, visit www.artproaudio.com.
- Select "Support" > "Return Authorization Request" to obtain an RA number.
- Pack the unit securely, preferably in its original carton or a suitable substitute, possibly in an additional shipping box. Clearly print the RA number on the outside of the shipping box.
- Include a note with the RA number, your contact information (including return shipping address, no P.O. boxes), a daytime phone number, and a description of the problem. Attach this note to the unit if possible. Include a copy of your purchase receipt.
For Your Reference:
Date of purchase: __________________________________
Purchased from: __________________________________
Serial Number: __________________________________
Specifications
| Parameter | Value |
|---|---|
| Input Connections | XLR female balanced (Mic, channels 1-8), 1/4-inch TS unbalanced (Line, channels 1-8), RCA unbalanced (Aux Bus In, Left and Right) |
| Output Connections | 1/4-inch TRS balanced (Main Outputs, Left and Right), RCA unbalanced (Prefade Out, Left and Right) |
| Input Impedance | 2k Ohms (Mic), 20k Ohms (Line), 51k Ohms (Aux Bus In) |
| Output Impedance | 200 Ohms (Main Outputs, balanced), 100 Ohms (Prefade Out) |
| Frequency Response | 20 Hz – 20 kHz (+0, -1 dB) (CH 1-8 in, Main out) |
| THD | <0.01% @ 1 kHz, typical |
| Phase Response | All connections are phase coherent |
| Signal to Noise Ratio | >99dB typical (Ref 0dBu) |
| CMRR | >43 dB typical |
| PAN Controls | Centered for level and gain measurements |
| Maximum Input Level | -4 dBu (Mic), +22 dBu (Line) |
| Maximum Output Level | +24 dBu (balanced), +18 dBu (unbalanced) |
| Maximum Gain | 54 dB (Mic), 29 dB (Line) |
| Phantom Power | Switch selectable, +48V DC (regulated and filtered), 7 mA current limiting per leg |
| Power Requirements | USA: 95-125 VAC, 50-60 Hz, <15W. Export units configured for country of destination. |
| Dimensions (HWD) | 1.75-inch x 19-inch x 6-inch (44.5mm x 483mm x 152mm) |
| Weight | 6.3 lbs. (2.9 kg) |
| Note | 0 dBu = 0.775Vrms |
ART maintains a policy of constant product improvement. ART reserves the right to make changes in design, or make additions to, or improvements upon, this product without any obligation to install the same on products previously manufactured. Therefore, specifications are subject to change without notice.
Website: www.artproaudio.com
Email: support@artproaudio.com
© 2017 Applied Research & Technology
Model: MX821S
Product: EIGHT CHANNEL MIC/LINE MIXER WITH STEREO OUTPUTS
Document ID: 821S5004103
