Microplane 901 user manual

Summary of the content on the page No. 1

Model 901

HEADPHONE AMPLIFIER
OWNERS MANUAL

PO Box 204 Boulder, CO 80306
tel: 303.443.7454 fax: 303.444.4634
email: info@gracedesign.com web: www.gracedesign.com
Revision A November, 2001 © Copyright 2001, Lunatec LLC

Summary of the content on the page No. 2

Thank you for purchasing the Model 901 headphone amplifier. It is designed to be completely reliable and easy to use. However, we ask that you take the time to familiarize yourself with some of the more important operation instructions in this manual to avoid most common user problems. The Model 901 amplifier is an ultra high fidelity monitoring device. By revealing all of the contents of your signal, we hope it helps you achieve a new level of excellence in your audio recordings. Fe

Summary of the content on the page No. 3

SAMPLE RATE POWER SWITCH LEVEL CONTROL INDICATOR GAIN RANGE INPUT SELECT OUTPUT JACK FRONT PANEL CONTROLS LEVEL CONTROL The 901 level control is assembled with an ultra precision 24 position gold contact switch. Using low inductance surface mount metal film resistors this switch is the ultimate attenuator for sonic fidelity and level accuracy. Left-right channel balance is maintained to within 0.05dB at any setting. The attenuation curve is shown in the table below. POSITION ATTEN

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INPUT SELECT This switch selects the input source. With the switch out the analog inputs are selected. XLR balanced and RCA unbalanced connectors are provided on the rear panel. When the INPUT SELECT switch is depressed the digital inputs are selected. AES3, S/PDIF and optical inputs are provided on the rear panel. A toggle switch on the rear panel selects between the AES and S/PDIF-optical inputs. SAMPLE RATE INDICATORS The LED sample rate indicators display the digital input sign

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REAR PANEL CONTROLS AC INLET The 901 accommodates a standard IEC power cable. The IEC inlet contains a built in RFI filter. LINE VOLTAGE SELECTOR To change the line voltage use a small screwdriver to pry open the voltage select door. Carefully remove the voltage select cam and insert with the desired voltage showing. Use the table below for voltage settings and fuse values. CAM SETTING LINE VOLTAGE FUSE VALUE 110Vac 100Vac 120Vac .25A SLOW 220Vac 220Vac 230Vac 240Vac

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ANALOG INPUTS The 901 provides both balanced and unbalanced inputs. Input connections are made using the female XLR connector on the rear panel. These connectors are wired with pin 2 positive, pin 3 negative and pin 1 ground. The unbalanced phono type jacks are wired in parallel with pin 2 of the XLR balanced jacks. Connecting unbalanced and balanced signals simultaneously is not recommended. Model 901 Specifications GAIN Normal Mode -∞ to +10dB Boost Mode -∞ to +20dB

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NOISE FLOOR 0dB gain, 22-22kHz -95dBu 0dB gain, A-weighted -102dBu POWER REQUIREMENTS 115VAC .16A 230VAC .08A 6