m201 Microphone Preamplifier / ADC Owner’s Manual Rev G All contents ©2012 Grace Design 4689 Ute Highway, Lyons, CO 80540 USA tel 1.303.823.8100 fax 1.303.823.8101 info@gracedesign.com / www.gracedesign.
Welcome Thank you for purchasing the Grace Design m201 microphone preamplifier. With the combination of unmatched sonic performance, useful features, and solid reliability, the m201 is a powerful recording tool designed to help you make the best recordings of your career. We have designed the m201 to be as easy and intuitive to use as possible. However, we strongly recommend that you read this product manual thoroughly to familiarize yourself with the unique features and capabilities of the m201.
Important Safety Information GENERAL • • • • • • • • • • • • • • Indoor use only Ordinary Protection: This equipment should not be exposed to dripping or splasing. Avoid placing objects filled with liquids, such as vases or glasses, on this equipment. Class I Equipment (grounded type) Electrical rating: 100-120/220/230-240V~ 50-60Hz 30W Mains supply voltage fluctuations are not to exceed ±10% of the nominal supply voltage.
Front Panel Controls 1 2 3 1 40 2 40 30 ribbon 50 (+10dB ) 48V 30 ribbon 50 (+10dB ) HI-Z HI-Z 130V 20 60 INPUT MODE m201microphone preamplifier 50m 50s 48V 130V 20 60 INPUT MODE 30m 70s 70m 30s 100m M+S WIDTH - 20dB +48V HI-Z +48V - 20dB HI-Z GRACE DESIGN USA 4 5 1. 6 7 24 position gold contact gain switch 5. Each gain control has 24 positions and adjusts the voltage gain from 18dB to 64dB in 2dB steps. In ribbon mode the gain range is 28dB to 74dB in 2dB steps.
Rear Panel Connections 6 OUT S/PDIF PUSH PUSH IN 4 TOSLINK 120Vac Pb AES 2 AES 1 PUSH 2 1 3 LEAD FREE 4 2 1 MIC IN 130 V 1 3 2 LINE IN M+S OUT PUSH 2 PUSH 1 RoHS COMPLIENT GRACE DESIGN USA 4 1. PUSH WC m201microphone preamplifier 5 LEFT RIGHT 3 OUT OUT MIC IN OUT OUT 2 MIC IN 1 XLR mic input connectors Input connections are made via female XLR connectors with pin 2 positive, pin 3 negative and pin 1 ground. 48V phantom power is supplied on pins 2 and 3. 2.
Audio Connections Microphone input connections are made via female XLR connectors with pin 2 positive, pin 3 negative and pin 1 ground. 48V phantom power is supplied on pins 2 and 3. Output connections are made via male XLR connectors with pin 2 positive, pin 3 negative and pin 1 ground. If the output is to be used unbalanced, pin 1 should be connected to signal ground and pin 2 to signal hot. Due to the nature of the balanced output stage, pin 3 should be left open for unbalanced operation.
60Hz. From the rear of the m201, open the trap door next to the IEC power inlet with a small screwdriver. Carefully pull the voltage select cam straight out and then insert with the desired voltage showing. Do not try to rotate the cam while it is in the power input module. Replace the fuses with the proper value selected from below. Be sure to use a time delay fuse with a 250V rating.
option is present, this selection will deactivate the standard XLR inputs and enable the dedicated 4 pin 130V XLR inputs. In this mode, the 48V pushbutton switch will turn on the 130V power supply. Phase reverse and -20dB pad are available in this mode. The dual balanced XLR outputs carry the output signal. Note: this option is no longer available. SETTING THE GAIN First, turn the gain control fully counter-clockwise and check that the 48V phantom power is off.
1 and 2 outputs while also recording (or monitoring) the stereo composite from the M-S LEFT and RIGHT outputs. Note: For more information on M-S recording we would highly recommend the AES paper written by Wes Dooley and Don Streicher called “M-S Stereo: A Powerful Technique for Working in Stereo”. This paper (No. 1792) is available from the Audio Engineering Society web page (www.aes.org).
Simply push the button to select the input source you require. FS SELECT The m201 A/D converter can operate at sampling rates of 44.1, 48,88.2, 96, 176.4, and 192kHz. Whether operating on the internal crystal or an external clock source, you must select the appropriate sampling rate at which you wish to record. The top left switch above the A/D bezel labeled FS SELECT is used to toggle between all the available sampling rates. Simply push the button to select the sampling rate you require.
Four standard sensitivities are supported in the m201 A/D converter: +18dBu = 0dBFS (14dB Headroom) +20dBu = 0dBFS (16dB Headroom) +22dBu = 0dBFS (18dB Headroom) +24dBu = 0dBFS (20dB Headroom). The front panel interface features a calibration mode that allows precise adjustment of the A/D sensitivity. To recalibrate one or both of the input sensitivity configurations, simply do the following: 1. Disconnect AC power from the m201. 2. Remove the 8 top cover screws using a #2 Phillips screwdriver.
CH2 (A): VR3 P5 P6 CH2 (B): VR4 J5 FRONT PANEL C42 P3 U11 C29 C20 U4 J4 -18V J2 C13 +15VA R9 C31 C21 R16 D1 K1 Q1 C10 U5 D2 R10 -15VA +6.5V +3.
2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Set all of the gain controls to the 30dB position. Connect the audio generator to the input of channel 1. Set the generator output level to approximately -20dBu @1KHz. If the generator has an unbalanced output, refer to figure 2 below for termination information Connect the level meter to the output of channel 1. If the level meter has an unbalanced input, refer to for unbalanced output termination information.
D1B D4B Q1B Q1A C38B C37B D4A C30B C29B C38A C37A C30A C29A D1A R5A K1A R5B K5A K3A D3A P2 U10B U6B U5B R38B R37B D10B C45B R63B C44B R62B D17B D16B R53B C35B D13B C43B C42B R61B R60B R52B R51B D14B J4B J3B CHANNEL 1 CHANNEL 2 VR2B U7B R26B R25B C23B C22B R69B R34B R33B D9B R30B R31B C25B C24B D7B D8B R29B R28B C27B R27B C13B C36B R59B R54B C39B R67B R16B R15B R18B R17B R14B C4B C46B R64B R55B R56B R50B C52 D15B J7B R45B R46B R39B R32B U1B U8B R40B Q3B Q2B R71 R48B R47
Cleaning Your m201 preamplifier chassis is constructed out of high quality stainless steel. Under normal circumstances, virtually no maintenance is required to keep the unit looking shiny and new. However, if your unit becomes smudged or dirty, here are some cleaning tips: We recommend using either Pledge furniture polish or Zep brand stainless steel cleaner (available at the hardware store).
Specifications preamplifier specifications (without A/D converter) Frequency Response @ 40dB gain ± 0.2dB (50Ω source) @ 40dB gain ± 3dB (50Ω source) 18Hz-65kHz 4.5Hz-350kHz THD+N @ 20dB gain +25dBu out, 1kHz <.0008% @ 40dB gain +25dBu out, 1kHz <.0009% @ 60dB gain +25dBu out, 1kHz <.0070% Intermodulation Distortion @ 40dB gain +25dBu out SMPTE/DIN 1:1 (50Hz, 7kHz) <.0020% SMPTE/DIN 4:1 (50Hz, 7kHz) <.
A/D module specifications (line input) Dynamic range 20Hz-20kHz >115dB “A” weighting >117dB THD+N 1kHz, -1dBFS, 20Hz-22kHz Frequency response < 0.00026% (-112dB) +/-0.2dB -3dB 44.1kHz Fs 5Hz-21kHz 22kHz 48kHz Fs 5Hz-23kHz 24kHz 88.2kHz Fs 5Hz-41kHz 44kHz 96kHz Fs 5Hz-45kHz 48kHz 176.4kHz Fs 5Hz-54kHz 72.
Signal Flow Diagram INPUTS CH1 MIC CH1 HI-Z CH1 DPA DPA INPUTS (OPTIONAL) INPUTS CH2 MIC CH2 HI-Z CH2 DPA DPA INPUTS (OPTIONAL) ADC INPUTS FROM PREAMP CH 1-2 6-CHANNEL FROM M-S OUTPUT LINE IN LEFT LINE IN RIGHT WORD CLOCK LOOP SYNC IN +48V -20dB -20dB -20dB HI-Z INPUT AMP +130V +48V -20dB HI-Z INPUT AMP +130V RIBBON +10dB +48 OFF RIBBON +10dB +48 OFF GRACE DESIGN SIDE MID m201 SIGNAL FLOW DIAGRAM MICROPHONE AMPLIFIER MICROPHONE AMPLIFIER CLK SELECT FS SELECT ADC INPUT SELECTOR
Warranty Information Grace Design warrants all of our products to be free of defective parts and workmanship for a period of five years. This warranty period begins at the original date of purchase and is transferable to any person who may subsequently purchase the product during this time. This warranty excludes the following conditions: normal wear and tear, misuse, customer negligence, accidental damage, unauthorized repair or modification, cosmetic damage and damage incurred during shipment.
Manual Revisions Revision Page A B 20 3 Change Date Initials Initial release 04/25/2007 mbg Changed voltage range and power specifications 04/26/2007 mbg B 4 Power switch description changed to standby switch.
