background image

 

MPA685 Owner’s Manual 

 

 

3/2012 

 

 

 

19

 

 

 

 

WARRANTY INFORMATION 

 
 

Ingram Engineering warrants all materials, workmanship and proper operation of this product 
for a period of three years from the original date of purchase.  If any defects are found in the 
materials or workmanship or if the product fails to function properly during the applicable 
warranty period, Ingram Engineering, at its option, will repair or replace the product.  This 
warranty applies only to equipment sold and delivered by Ingram Engineering or its authorized 
dealers.  Original purchase receipts showing date and location of purchase must be presented 
at the time of submission for warranty work. 
 
Failure to register the product will not void the three year warranty. 
 
Service and repairs of Ingram Engineering products are to be performed only at the factory OR 
at an authorized Ingram Engineering Service Center.  Unauthorized service, repairs, or 
modification will void this warranty.  To obtain repairs under warranty, you must have a copy of 
your sales receipt from the store where you bought the product.  It is necessary to establish 
purchase date and thus determine whether or not your Ingram Engineering product is still 
under warranty.

  

 

To obtain factory service:   

1.  Call Ingram Engineering at 678-685-9838 9 AM to 5 PM Monday through Friday (East 

Coast Time) to get a Return Authorization (RA).  Products returned without an RA 
number will be refused.  

2.  Pack the product in its original shipping carton.  If you do not have the carton, just ask 

for one when you get your RA number, and we’ll send a shipping carton to you.  Please 
seal the product in a plastic bag.  

3.  Also include a note explaining exactly how to duplicate the problem, a copy of the sales 

receipt showing price and date, and your return street address (no P.O. boxes or route 
numbers, please).  If we cannot duplicate the problem or establish the starting date of 
your Limited Warranty, we may, at our option, charge for service time.  

4.  Ship the product in its original shipping carton, 

freight prepaid

 to: 

Ingram Engineering Service Department 
926 Bruce Circle 
Atlanta, Ga. 30316 USA    

 

IMPORTANT:  Make sure that the RA number is plainly written on the shipping carton. 

 
To obtain service from an Authorized Ingram Engineering Service Center: 

1.  Call Ingram Engineering at 678-685-9838, 9 AM to 5 PM Monday through Friday (East 

Coast Time) to receive:  1) The name and address of your nearest Authorized Ingram 

Summary of Contents for MPA685

Page 1: ...MPA685 Dual Channel Microphone Preamplifier Owner s Manual INGRAMENGINEERING Option 201...

Page 2: ...MPA685 Owner s Manual 3 2012 2...

Page 3: ...ophone Impedance Selector 5 Adjusting the Audio Input Level Settings 6 Overload LED 7 48V Switch 8 Phase Invert 9 High Pass Filter 10 Adjusting the Output Level Audio Specifications AC Specifications...

Page 4: ...le this preamplifier to be used with any microphone type and any audio signal with outstanding results DESCRIPTION The MPA685 provides two channels of 100 discrete semiconductor based amplification of...

Page 5: ...ns Extremely tight gain matching between channels along with the transformer usage and discrete circuit design also makes the MPA685 an excellent choice for stereo make up gain applications High volta...

Page 6: ...LOAD LED BUFFER BUFFER LOW FREQ RESPONSE SWITCH OUTPUT BUFFER OUTPUT LEVEL POT STEPPED SWITCH ATTN DIRECT LOOPTHRU GAIN STAGE GAIN STEPPED SWITCH MIC Z BLOCK DIAGRAM A block diagram of the MPA685 is s...

Page 7: ...to a power supply only of the type described in these operation instructions or as marked on this product 8 Power Cord Protection Power supply cords should be routed so that they are not likely to be...

Page 8: ...plug with an extension cord receptacle or other outlet unless the blades can be fully inserted to prevent blade exposure 13 Grounding or Polarization Precautions should be taken so that the grounding...

Page 9: ...s are made with standard ITT Cannon XLR 3 31 and 3 32 types XLR audio input and output connections are balanced with pin 2 positive Pin 3 negative and Pin 1 ground A ground lift toggle switch is inclu...

Page 10: ...p through may therefore dominate the instrument load if the loop through load is less than 1 Meg If excessive signal loading is experienced when using the loop through connection remove the loop throu...

Page 11: ...t section stepped switch functions as a combined attenuator gain control When the switch is adjusted between 11 and 1 on the front panel the switch is attenuator mode and the pre amp gain stage operat...

Page 12: ...Gain vs Stepped Switch Position 6 Overload LED The Overload LED is designed to illuminate at 1 THD The Overload detection circuitry accurately tracks the 1 THD threshold to frequencies higher than 30...

Page 13: ...of the audio at the pre amplifier output is 180 relative to the input 9 Low Frequency Response Switch The Low Frequency Response filter applies a 6dB octave cut to low frequencies when activated To a...

Page 14: ...ut High Setting 69 dB Direct Input Stepped Switch Gain Change vs Switch Position 4 dB Step Switch Positions 11 to 10 2 dB Step Switch Positions 10 to 4 3 dB Step Switch Positions 4 to 7 4 dB Step Swit...

Page 15: ...otherwise noted Parameter Min Typ Max Unit Comments AC Voltage 115 230 V Selectable on rear panel AC Frequency 50 60 Hz Fuse 500 mA 250 V Slow Blow Size 0 25 x 1 25 3AG or 5x20mm GDC 213 depends on A...

Page 16: ...crewdriver may be used to eject the fuse holder from the housing The fuse type is specified in the Specifications section 2 Power On Bulb Use only Chicago Miniature Type 756 bulb Other bulbs have the...

Page 17: ...assembly and remove the bulb by pushing the bulb in and turning to the left Replace the bulb with the type listed in the Specifications section 3 Microphone Input Audio Sounds Distorted Decrease the...

Page 18: ...ground In the event that the ground lift toggle switch does not eliminate hum Pin 1 of the cable connected to the pre amplifier output may be disconnected at the connection to the pre amplifier If hu...

Page 19: ...ate and thus determine whether or not your Ingram Engineering product is still under warranty To obtain factory service 1 Call Ingram Engineering at 678 685 9838 9 AM to 5 PM Monday through Friday Eas...

Page 20: ...sales receipt Final determination of warranty coverage lies solely with Ingram Engineering or its Authorized Service Centers Ingram Engineering products returned to Ingram Engineering and deemed eligi...

Page 21: ...LY LIMITED IN DURATION TO THREE YEARS FROM THE DATE OF ORIGINAL PURCHASE FROM AN AUTHORIZED INGRAM ENGINEERING DEALER UPON EXPIRATION OF THE APPLICABLE WARRANTY PERIOD INGRAM ENGINEERING SHALL HAVE NO...

Page 22: ...cts and or documents or to discontinue any product at any time without notice The product specifications contained herein are subject to change Ingram Engineering assumes no responsibility for inaccur...

Reviews: