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Related Manuals for Benchmark PRE420
Summary of Contents for Benchmark PRE420
- Page 1 Benchmark PRE420 Instruction Manual 4-Channel Microphone Preamplifier/Mixer...
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Page 2: Safety Information
EQUIVALENT). Modifications CAUTION: DO NOT SUBSTITUTE PARTS OR MAKE ANY MODIFICATIONS WITHOUT THE WRITTEN APPROVAL OF BENCHMARK MEDIA SYSTEMS, INC. MODIFICATION MAY CREATE SAFETY HAZARDS AND VOID THE WARRANTY. NOTICE: CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY BENCHMARK MEDIA SYSTEMS COULD... -
Page 3: Table Of Contents
Terminating Unused Inputs RoHS Compliant Information 40 Hz High-Pass Filters CE Certificate of Conformity LED Meters – Direct Outputs Warranty Information Solo Bus Benchmark Extended Warranty Solo Switches Calibration Stereo/Mono Solo Switch Required Equipment Control Room Outputs +48V Adjustment Control Room Mute Switch... -
Page 4: Overview
The entire signal path of the PRE420 has a A solo bus allows monitoring of individual generously wide bandwidth: 500 kHz. This microphones as well as any stereo or mono creates a significant demand for exceptional mix of microphones. - Page 5 Benchmark MPS series preamps have always had outstanding high-frequency performance as well as freedom from IMD. The PRE420 takes the Benchmark design one step further, and achieves the lowest IMD that we have ever measured in a microphone preamplifier.
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Page 6: Features
+48V Phantom Warning Indicators (Yellow - 1 per input channel) • Power LED (Blue) • Ultra-Quiet Linear Power Supply with Rear-Panel Input Voltage Selector • Complies with FCC and CE Regulations • RoHS Compliant • PRE420 Instruction Manual – rev. E Page 6... -
Page 7: Connections
RF the choke (J5-J12). The frequency response shielding and for immunity to hum due to of the PRE420’s is 500 kHz, but the choke will shield currents. limit the frequency response of an un-... -
Page 8: Driving Unbalanced Loads
50 to 60 Hz. At the “110” setting, brightness at an output level of about +4 the PRE420 will operate normally over a range of 105 to 140 VAC. At the “220” dBu, and is near full brightness at +24 dBu. -
Page 9: Preamp Section
Preamp Section Blocking RF, EMI, and Noise The entire signal path of the PRE420 has a generously wide bandwidth: 500 kHz. This creates a significant demand for exceptional RF filtering and shielding – a demand Benchmark fulfills. All signal paths in the PRE420 are aggressively protected from RF and EMI (electro-magnetic interference). - Page 10 The worst possible transients occur when a microphone cable has an intermittent short to ground from either pin 2 or pin 3. The PRE420 is very well protected against both of the above. For the protection of your microphones (and...
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Page 11: Mirrorpan™ Pan Controls
Each preamp channel has a direct output. pad, the maximum input level is 7 dBu. The Each direct output is equipped with a two- input impedance of the PRE420 is 1.37k segment LED meter. Ohms with the pad enabled and 8.13k Ohms when the pad is off. -
Page 12: Solo Bus
If none of the 4 microphone solo buttons are Solo Bus pressed, the main stereo mix is directed to the solo bus. The PRE420 has a flexible solo bus that NOTE: The “Mono/Stereo” switch is only allows: functional when one or more microphone solo buttons are pressed. -
Page 13: Control Room Outputs
3. Make no connection to XLR pin 3 (-). XLR to ¼” TS Wiring: 1. Connect XLR pin 2 (+) to Tip. 2. Connect XLR pin 1 (GND) to Sleeve. 3. Make no connection to XLR pin 3 (-). PRE420 Instruction Manual – rev. E Page 13... -
Page 14: Hpa2™ Headphone Output
Headphone Performance In our tests we have measured substantial distortion across resistors that are wired in series with headphones. We conducted measurements with a variety of headphones. In general, distortion increases as headphone PRE420 Instruction Manual – rev. E Page 14... -
Page 15: Mix Outputs
LED is just illuminated. 1. Connect XLR pin 2 (+) to Tip. 2. Connect XLR pin 1 (GND) to Sleeve. 3. Make no connection to XLR pin 3 (-). PRE420 Instruction Manual – rev. E Page 15... -
Page 16: Rack Mounting
CAUSE MAGNETICALLY INDUCED HUM IN THE SENSITIVE HIGH-GAIN PREAMP CIRCUITS. The PRE420 may be mounted directly above or below other PRE420 preamps. It may also be mounted directly above or below Benchmark DAC1 and ADC1 converters. The Pre420 is well shielded but we cannot... -
Page 17: Performance Graphs
Left HP Filter Off The above graph shows the frequency response of the PRE420 with the 40 Hz high-pass filter off. The amplitude response measures -0.020 dB at 10 Hz and -0.165 dB at 200 kHz. The bass response extends well below the 10-Hz limitation of the test equipment, and the high-frequency response extends well above the 200 kHz limit of the test equipment. -
Page 18: High-Pass Filter - Frequency Response
Solid Anlr.Level A Left HP Filter On The above graph shows the response of the 40 Hz high-pass filter. Response is -3 dB at 40 Hz with a slope of 12 dB/octave. PRE420 Instruction Manual – rev. E Page 18... -
Page 19: Inter-Channel Phase Response
+0.2 +0.1 -0.1 -0.2 -0.3 -0.4 -0.5 -0.6 -0.7 -0.8 -0.9 100k This graph shows that the differential phase is significantly better than ± 0.05 degrees from 10 Hz to 20 kHz. PRE420 Instruction Manual – rev. E Page 19... -
Page 20: Thd+N Vs. Frequency
THD+N vs. Frequency Measurement Bandwidth = 10Hz to 80 kHz, Gain = 30 to 60 dB, Output Level = +4 dBu Audio Precision PRE420 - THD+N vs Frequency at 60 dB Gain, BW=80 kHz 02/21/07 09:56:41 0.01 0.005 0.002 -100 0.001... -
Page 21: Wideband Thd+N Vs. Frequency
Wideband THD+N vs. Frequency Measurement Bandwidth = 10 Hz to 500 kHz, Gain = 30 to 60 dB, Output Level = +4 dBu Audio Precision PRE420 - Wideband THD+N vs Frequency, BW=500 kHz 02/19/07 16:16:11 0.05 0.02 0.01 0.005 0.002 -100 0.001... -
Page 22: Equivalent Input Noise Vs. Gain
Equivalent Input Noise vs. Gain The above plot shows the Equivalent Input Noise (EIN) of the PRE420 as a function of gain. Measurement bandwidth is 20 Hz to 20 kHz. Input termination is 150 Ohms. PRE420 Instruction Manual – rev. E... -
Page 23: Noise Spectrum
*-149.014 dBr A The above graph demonstrates that the PRE420 is free of hum and noise. The highest tone is 60- Hz line-related hum and is at a level equivalent to an input level of -145 dBu. 180-Hz hum is at an equivalent input level of -149 dBu. -
Page 24: Thd Spectrum At 1 Khz
*-111.404 dBr A *-122.747 dBr A The above FFT plot shows that the PRE420 has very little harmonic distortion. The 1 kHz test tone is notched out with a THD analyzer to improve the resolution of the test. Distortion is exceptionally low. -
Page 25: Thd Spectrum At 10 Khz
*-109.271 dBr A *-118.787 dBr A The above FFT plot shows that the PRE420 has very little harmonic distortion at high frequencies. The 10 kHz test tone is notched out with a THD analyzer to improve the resolution of the test. The 20-kHz 2 -harmonic distortion measures better than -109 dB. -
Page 26: Specifications
-101 dB, 0.00085% at 55 dB Gain IMD (50Hz and 7 kHz, to any output at +24 dBu) -104 dB, 0.0006% at 35 dB Gain -104 dB, 0.0006% at 40 dB Gain PRE420 Instruction Manual – rev. E Page 26... -
Page 27: Direct Outputs
Monitor Gain Control L/R Balance +/- 0.01 dB at full clockwise rotation +/- 0.3 db at middle of rotation Drive capability at rated THD+N 300 Ohms Output Type Transformerless Voltage and Impedance Balanced PRE420 Instruction Manual – rev. E Page 27... -
Page 28: Mirrorpan™ Constant-Power Pan Circuit
Current limited at 300 mA Thermal Shutdown Bandwidth > 500 kHz -0.014 dB at 10 Hz -0.013 dB at 200 kHz THD+N -106 dB, 0.0005% into 30 Ohms at +18dBu (1.26 W) PRE420 Instruction Manual – rev. E Page 28... -
Page 29: Led Status Indicators And Meters
220 V setting : 200 V min, 285 V max Frequency 50-60 Hz Power 27 Watts Idle 27 Watts Typical Program 35 Watts Maximum Fuses 5 x 20 mm (2 required) 0.5 A 250 V Slo-Blo® Littelfuse® HXP218.500 or Equivalent PRE420 Instruction Manual – rev. E Page 29... -
Page 30: Dimensions
Height excluding removable feet 1.725” (43.8 mm) Weight PRE420 only 8.05 lb. (3.65 kg) PRE420 with power cord, extra fuses, and manual 9 lb. (4.1 kg) Shipping weight 11 lb. (5 kg) PRE420 Instruction Manual – rev. E Page 30... -
Page 31: Regulatory Compliance
(European Union) directive 2002/95/EC, or, RoHS (Restrictions of Hazardous Substances). As of July 01, 2006, All Benchmark Media Systems, Inc. products placed on the European Union market are compliant (containing quantity limit weight less than or equal to 0.1% (1000 ppm) -
Page 32: Ce Certificate Of Conformity
CE Certificate of Conformity PRE420 Instruction Manual – rev. E Page 32... -
Page 33: Warranty Information
In the event of failure of a product under this warranty, Benchmark Media Systems, Inc. will repair, at no charge, the product returned to its factory. Benchmark Media Systems, Inc. may, at its option, replace the product in lieu of repair. -
Page 34: Benchmark Extended Warranty
Benchmark Extended Warranty The Benchmark Extended 5* Year Warranty Benchmark Media Systems, Inc. optionally extends the standard one (1) year warranty to a period of five (5)* years from the date of delivery. *For the extended warranty to become effective, the original purchaser must register the product at the time of purchase either by way of the prepaid registration card or through the product registration section of the Benchmark Media Systems, Inc. -
Page 35: Calibration
BE USED BY A QUALIFIED TECHNICIAN. 9. Adjust channel 1 “Meter Threshold” (R13) so that CH1 red LED just turns This procedure will restore the PRE420 to factory calibration if controls have been on. This sets the meter to the factory moved from factory settings. -
Page 36: Main Gain Balance
“Main” L & R outputs are balanced. Peak LED Adjust --- - Main Outputs 33. Release all push buttons on front panel. 34. Microphone 1 “Gain” control must be fully clockwise. PRE420 Instruction Manual – rev. E Page 36... - Page 37 Copyright © 2007 Benchmark Media Systems, Inc. All rights reserved. Benchmark Media Systems, Inc. 203 Hampton Place, Ste. 2 Syracuse, NY 13206 +1-315-437-6300, FAX +1-315-437-8119 www.benchmarkmedia.com PRE420 Instruction Manual – rev. E Page 37...
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