MIDAS 500 Series Microphone Preamplifier 502 User Guide

Quick Start Guide

500 SERIES MICROPHONE PREAMPLIFIER 502
500 Series Modular Midas Microphone Preamplifi er with
Classic XL4 Filters

Important Safety Instructions

Terminals marked with this symbol carry an electrical current of sufficient magnitude to constitute a risk of electric shock. Use only high-quality professional speaker cables with ¼” TS or twist-locking plugs pre-installed. All other stallation or modification should be performed only by qualified personnel.

This symbol, wherever it appears, alerts you to the presence of uninsulated dangerous voltage inside the enclosure – voltage that may be sufficient to constitute a risk of shock.

This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature.
Please read the manual.

Caution
To reduce the risk of electric shock, do not remove the top cover (or the rear section). No user-serviceable parts inside. Refer servicing to qualified personnel.

Caution
To reduce the risk of fire or electric shock, do not expose this appliance to rain and moisture.  The apparatus shall not be exposed to dripping or splashing liquids and no objects filled with liquids, such as vases, shall be placed on the apparatus.

Caution
These service instructions are for use by qualified service personnel only. To reduce the risk of electric shock do not perform any servicing other than that contained in the operation instructions. Repairs have to be performed by qualified service personnel.

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug.
   A polarized plug has two blades with one wider than the other. A grounding- type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety.
   If the provided plug does not fit into your outlet, consult an electrician for the replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.

11. Use only attachments/ accessories specified by the manufacturer.

12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.

13. Unplug this apparatus during lightning storms or when unused for long periods of time.

14. Refer all servicing to qualified service personnel.
    Servicing is required when the apparatus has been damaged in any way, such as power supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

15. The apparatus shall be connected to a MAINS socket outlet with a protective earthing connection.

16. Where the MAINS plug or an appliance coupler is used as the disconnect device, the disconnect device shall remain readily operable.

17.  Correct disposal of this product: This symbol indicates that this product must not be disposed of with household waste, according to the WEEE Directive (2012/19/EU) and your national law. This product should be taken to a collection center licensed for the recycling of waste electrical and electronic equipment (EEE). The mishandling of this type of waste could have a possible negative impact on the environment and human health due to potentially hazardous substances that are generally associated with EEE. At the same time, your cooperation in the correct disposal of this product will contribute to the efficient use of natural resources. For more information about where you can take your waste equipment for recycling, please contact your local city office or your household waste collection service.

18. Do not install in a confined space, such as a bookcase or similar unit.

19. Do not place naked flame sources, such as lighted candles, on the apparatus.

20. Please keep the environmental aspects of battery disposal in mind. Batteries must be disposed of at a battery collection point.

21. Use this apparatus in tropical and/or moderate climates.

LEGAL DISCLAIMER

Music Tribe accepts no liability for any loss which may be suffered by any person who relies either wholly on or in part upon any description, photograph, or statement contained herein. Technical specific cations, appearances, and other information are subject to change without notice.
All trademarks are the property of their respective owners. Midas, Klark Teknik, Lab Gruppen, Lake,  Tannoy, Turbosound, TC Electronic, TC Helicon, Behringer, Bugera, Auratone, and Coolaudio are trademarks or registered trademarks of  Music Tribe Global Brands Ltd.© Music Tribe Global Brands Ltd. 2019 All rights reserved.

LIMITED WARRANTY

For the applicable warranty terms and conditions and additional information regarding Music Tribe’s Limited Warranty, please see complete details online at musictribe.com/warranty.
Zhongshan Eurotec Electronics Limited No. 10 Wanmei Road, South China Modern Chinese Medicine Park, Nanyang Town, 528451,  Zhongshan City, Guangdong Province, China

Controls

1. Mounting holes – The 502 module is mounted to the host 500 series rack chassis or boxes such as the Midas Legend L6 or L10, and secured using two screws top and bottom.

2. Rotary input level meter – This precision 11-segment peak-reading rotary input meter has a range from -20 dBu to +20 dBu in 4 dB steps. The meter reads the post-mic-amp, pre-filter signal, to allow precise setting of the input gain.

3. Input gain control – The mic /line input gain is a precision 12-position rotary switch with gain settings of 0 (unity gain), +10, +15,  +20, +25, +30, +35, +40, +45, +50, +55, and +60 dB. The switch is accurate to within +/- 1 dB at any gain setting. When set to the  “0” position, the input is capable of receiving input signal levels of up to +24 dBu, so it can easily deal with very high-level line signals without the need for a pad. The mic amp is the same design as used in the Midas Pro series consoles etc. It has been enhanced with quad discrete input transistors.

4. 48V switch – When this switch is selected, the 502 module supplies +48 Volts phantom power to the microphone via the 500 series rack input connector. The switch’s red LED illuminates to show that +48V is on. Note: Do not select phantom power unless you are sure that your microphone requires it. Microphones and other audio devices can be damaged by phantom power. When switching the +48V on or off, it is recommended that any connected amplifiers are switched off or muted to avoid DC thumps heard in the speakers.

5. Low pass filter control – This knob adjusts the low-pass filter frequency in the range of 1 kHz to 40 kHz (-3 dB points).
   Starting from 40 kHz, turn the control anticlockwise gradually to remove any unwanted HF noise or audio. It can also be useful to create a more vintage sound.

6. Low pass filter IN switch – The IN switch next to the low pass control knob inserts the low pass filter into the signal path, post-input-gain, and pre output-trim control. The switch’s yellow LED illuminates to show that the LP filter is active.

7. Phase reverse Ø switch – When this switch is selected, the signal phase is reversed by 180°. The switch’s green LED illuminates to show that Ø reverse is on.

8. High pass filter control – This knob adjusts the high-pass filter frequency in the range of 10 Hz to 400 Hz (-3 dB points).
   Starting at 10 Hz, turn the control gradually clockwise to remove any unwanted low-frequency content.

9. High pass filter IN switch – The IN switch next to the high-pass control knob inserts the high pass filter into the signal path, post-input-gain, and pre output-trim control. The switch’s yellow LED illuminates to show that the HP filter is active.

10. TX switch – When this switch is selected, the twin aux balanced output is enabled if the module is fitted in a Midas L6, L10, or compatible 500 series rack, equipped with a balanced aux output XLR. This gives active mic/line splitter capability. The main output is not affected by the TX switch. The twin aux output should not be selected if used in a 500 series rack that is not equipped with a suitable balanced aux output connector.
    (Please check the module pinout if uncertain.) The TX switch’s green LED illuminates when the twin aux output is enabled.

11. Rotary output level meter – The precision 11-segment peak-reading rotary output meter has a range from -20 dBu to +20 dBu in 4 dB steps. The meter reads the output signal level to allow the precise setting of the output trim control.

12. Output trim control – This rotary output trim potentiometer gives precise control of the output signal level. It has a range of +/- 20  dB with a 0 dB center.
    When used in conjunction with the input gain control, the total maximum gain is +80 dB, more than enough for low-level ribbon microphones, etc. In addition, the output trim control can be used to control coloration, the mic input gain can be increased to take advantage of the overload tolerant Midas mic amp, the output trim can be turned down to prevent the output level from running too high.

Getting Started

1. The 502 modules are designed to be mounted into a 500 series rack chassis or box, such as the Midas Legend L6 and L10. The L6/L10 supplies the input and output connections to the 502 modules, as well as internal power and phantom power to run the module.

2. With the power to the L6/L10 turned off, install the 502 modules by sliding them in carefully so its rear connector correctly fits into the corresponding multi-pin connector of the L6/L10. Use 2 screws to secure the 502 modules to the front top and bottom rails.

3. Blank spaces in your L6 or L10 can be filled using the Midas L1B blank plates. These plates will prevent dirt, dust, and other objects from entering the unit.

4. Insert any other modules in your system.

5. Connect your microphone and other audio equipment to the input and output of the L6/L10.

6. The 502 modules can provide +48V phantom power if your microphone needs it. Note: Do not select phantom power unless you are sure that your microphone requires it. Microphones and other audio devices can be damaged by phantom power.
   When switching the +48V on or off, it is recommended that any connected amplifiers are switched off or muted to avoid DC  humps heard in the speakers.

7. Turn on the power to the L6/L10.
   The 502 modules is equipped with an internal power on/off a mute relay.
   After power-up, there is a 2-second delay before the output is connected, to avoid power-on thumps. The relay also prevents power-off thumps by muting the output during power down. Tip: If +48V is required, select the +48V switch before powering up your  L6/L10. Then power-up, the relay mute will prevent the +48V switch-on thump from being heard.

Specifications

Controls

Phantom Power| 48 V switch
Input gain, mic/line| 12 position rotary switch, 0-60 dB knob
Polarity| 0/180 degrees switch
Low pass filter| In/out switch, the frequency knob
High pass filter| In/out switch, the frequency knob
Output trim /line gain trim| +/-20 dB knob
Twin aux output enable| TX switch
Input and Output
Input| Mono, balanced mic or line
Main output| Mono, electronically balanced
Twin aux output| Mono, electronically balanced
System
Noise
Noise at unity gain| -97 dBu (22 Hz – 22 kHz)
Mic EIN noise at +60 dB gain, 150 Ohm source| 127 dBu (22 Hz – 22 kHz)
CARR
Unity gain, 1 kHz| -70 dB (typical)
+60 dB gain, 1 kHz| -100 dB (typical)
Input impedance, 1 kHz| 10 kO
Frequency response, unity gain| 20 Hz – 40 kHz +/- 0.5 dB
Distortion,unity gain, 1 kHz|
---|---
0 dBu| <0.005%
+10 dBu| <0.005%
+20 dBu| <0.01%
Maximum input level, 1 kHz| +24 dBu
Maximum output level, lkHz| +26 dBu
Output impedance, 1 kHz| 50 0
Filters|
Low pass| 1 kHz to 40 kHz, slope = 12 dB per octave
High pass| 10 Hz to 400 Hz, slope = 12 dB per octave
Meters|
Input meter| 11 segment, -20 dBu to +20 dBu in 4 dB steps
Output Meter| 11 segment, -20 dBu to +20 dBu in 4 dB steps
Power Requirements|
Voltage| +16 V and -16 V, +48 V (phantom power)
Power consumption| 100 mA, 3.2 W
Physical|
Dimensions (H x W x D)| 132 x 38 x 174 mm (5.2 x 1.5 x 6.9″)
Weight| 0.6 kg (1.3 lbs)

Module Connector Pin-Outs

Notes
L6 and L10 rackmount chassis XLR connections are wired pin 1 = audio GND, pin 2 = + (hot), pin 3 – (cold)

Block Diagram

Important information

1. Register online.
   Please register your new Music Tribe equipment right after you purchase it by visiting midasconsoles.com.
   Registering your purchase using our simple online form helps us to process your repair claims more quickly and efficiently. Also, read the terms and conditions of our warranty, if applicable.

2. Malfunction. Should your Music Tribe Authorized Reseller not be located in your vicinity, you may contact the Music Tribe Authorized Fulfiller for your country listed under “Support” at midasconsoles.com. Should your country not be listed, please check if your problem can be dealt with by our “Online Support” which may also be found under “Support” at midasconsoles.com. Alternatively, please submit an online warranty claim at midasconsoles.com BEFORE returning the product.

Important information:
Changes or modifications to the equipment not expressly approved by Music Tribe can void the user’s authority to use the equipment.

Warning:
The operation of this equipment in a residential environment could cause radio interference.

References

• Midas | Home
• Music Tribe

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