m201 microphone preamplifier optional A/D converter module manual Rev D owner’s manual all contents ©2007 Grace Design/ Lunatec LLC
Welcome Thank you for purchasing the Grace Design m201 microphone preamplifier. With the combination of unmatched sonic performance, powerful 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. •Pollution Degree 2 •Installation (Overvoltage) Category II for transient overvoltages.
Front Panel Controls A B C 1 40 2 40 48V 30 ribbon 50 (+10dB ) 30 50 HI-Z 60 INPUT MODE ribbon (+10dB ) HI-Z 130V 20 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 D E F 24 position gold contact gain switch A 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 E WORD/LOOP CLOCK PUSH m201microphone preamplifier S/PDIF PUSH PUSH IN 4 1 3 TOSLINK OUT LEAD FREE 120Vac Pb PUSH 2 4 2 1 MIC IN 130 V 1 3 2 LINE IN AES3 OUT M+S OUT PUSH 2 PUSH 1 RoHS COMPLIENT GRACE DESIGN USA D LEFT RIGHT C OUT OUT MIC IN OUT OUT B MIC IN A A 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.
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.
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.
ribbon This setting puts the m201 into ‘ribbon mic mode’, which is described in detail below. Use this input for ribbon microphones or any application where an additional 10dB of gain may be required. In this position, the main XLR mic inputs are feeding the preamplifier and the dual XLR outputs are active. 130V This setting activates the optional 130V input module for DPA microphones.
has completely discharged and then the ribbon mode will activate automatically. An additional benefit of the ribbon mic mode is that the input DC blocking capacitors are relay bypassed to further simplify the m201’s signal path. Incidentally, the ribbon mode works very well with many lower output dynamic microphones as well as ribbon types. M-S recording with the m201 In M-S mode the m201 accepts the Mid signal in channel 1 and the Side signal in channel 2.
A FS SELECT this switch is used to toggle through the available ADC sampling rates B CLOCK SOURCE this switch is used to select the ADC clock source C ADC MODE this switch is used to select single or dual wire AES, and switch between either professional or consumer fomat D OVER lights illuminate when the ADC has been overload- ed, and remain lit until the PEAK RESET swich is pushed E PEAK RESET / MODE This switch is used to clear peaks on the 20 segment led meter and to select how the meters display peak
all the available sampling rates. Simply push the button to select the sampling rate you require. The selected rate will be illuminated green below. Selecting “OFF” puts the A/D converter circuitry in low power standby mode with all oscillators off. CLOCK SOURCE The m201 A/D can be run from the internal crystal, an external word clock source, or from DigidesignTM loopsync*. The top middle switch, labeled CLOCK SOURCE, is used to select between these options.
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. Lift the top cover off the unit and set it aside. 3) Reconnect AC power to the m201 and turn it on. 4) Connect a signal generator to the A/D LINE inputs. Set the signal generator output to +4dBu @ 1kHz (1.
10) Once all desired calibration adjustments have been made, press and hold the INPUT SENS button for approximately 3 seconds. This will exit CAL mode and return the A/D to normal operation. The new settings are now stored until future changes are made. 11) Power down the unit, disconnect the AC power and reinstall the top cover.
Maintenance The model m201 was designed to be maintenance free for many years. It is highly unlikely that your unit will require service. However, there are two adjustments that may need to be made from time to time. These procedures should be made only by a qualified service technician or at the Grace Design factory. PEAK LED ADJUSTMENT PROCEDURE The peak LED threshold levels may be adjusted to a user defined operating level.
INPUT OFFSET ADJUSTMENT The input amplifiers in the m201 are ultra-precision laser trimmed devices which have a very low input offset. However, even the smallest differential offset at the input can result in an audible “click” when the gain control is turned. It should be noted that this type of click will be audible when no signal is present. With no signal present there is no signal amplitude to be changed unless input offset is present.
D1B D4B Q1B Q1A C38B C37B D4A C30B C29B C38A C37A C30A C29A D1A R5A K1A R5B K5A K3A D3A P2 U5B R38B R37B D10B CHANNEL 1 CHANNEL 2 C45B R63B C44B R62B D17B D16B R53B C35B D13B C43B C42B R61B R60B R52B R51B D14B J4B J3B P7 grace design m201 owner’s manual U6B R26B R25B C23B C22B FRONT PANEL 16 U7B C25B C24B D7B D8B R29B R28B C27B R27B C13B U10B VR2B C4B R34B R33B D9B R30B R31B R69B R16B R15B R18B R17B R14B C1B C36B
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 @ 40dB gain +25dBu out, 1kHz @ 60dB gain +25dBu out, 1kHz <.0008% <.0009% <.0070% Intermodulation Distortion @ 40dB gain +25dBu out SMPTE/DIN 1:1 (50Hz, 7kHz) SMPTE/DIN 4:1 (50Hz, 7kHz) <.0020% <.
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 20 Change Date Initials Initial release 04/25/2007 mbg B 3 Changed voltage range and power specifications 04/26/2007 mbg B 4 Power switch description changed to standby switch.
