PRELIMINARY Model 9762 ALL INFORMATION SUBJECT TO CHANGE DUAL-COMBO MICROPHONE PREAMPLIFIER Owners Manual RTZ Professional Audio 4260 Pine Vista Blvd Alpharetta, GA 30022 USA http://www.rtzaudio.
TABLE OF CONTENTS 1 WELCOME!............................................................................................................................. 1 2 OVERVIEW ............................................................................................................................. 1 3 AC VOLTAGE SELECT AND SAFETY FUSES .................................................................... 2 3.1 INTERNAL PREAMPLIFIER SAFETY FUSES ................................................................
Model 9762 – Dual Combo Owners Manual 1 Welcome! Thank you for purchasing your new Model 9762 Dual-Combo Microphone Preamplifier! Before operating or installing the unit, please read this manual thoroughly and retain it for future reference. Additional copies of this manual are available upon request or from our website at http://www.rtzaudio.com. All units are carefully packed to endure the rigors of shipping and handling. However, please inspect all contents and packaging immediately upon receipt.
Model 9762 – Dual Combo Owners Manual 3 AC Voltage Select and Safety Fuses The 9762 may be configured for either 115V or 230V operation at 50 / 60 Hz via the line voltage select card inside the power entry module on the rear panel. Always disconnect power and remove all connectors from the unit before servicing or changing the line voltage configuration. 3.1 Internal Thermal Safety Fuses The +24V status LED’s on each channel show power and regulator status for that channel.
Model 9762 – Dual Combo Owners Manual 4 Installation and Connections The 9762 is designed for standard 1U 19” rack mounting. Ideally, the unit should be mounted where cool air flows across the unit. Do not obstruct the flow of air around and across the preamplifier enclosure. In tight equipment enclosures, consider placing a ventilated rack panel to allow increased airflow.
Model 9762 – Dual Combo Owners Manual 5 Design Features The 9762 has been designed and built with great attention to detail. In particular, the input transformer and gain stepping network have been painstakingly matched and optimized to present the proper load impedance to the microphone at all gain settings. This refinement combined with a super high quality input transformer gives the 9762 a more detailed sound when compared to vintage units.
Model 9762 – Dual Combo 5.3 Owners Manual Gain Blocks and Metering The 9762 provides up to 75 dB maximum gain using a dual gain block type design. Gain is selectable from –20 dB to -75 dB in 5 dB increments via the twelve position rotary switch. At higher gain settings (above -50 dB), a second gain block is inserted into the signal path for additional gain and increased headroom. The input signal stages are designed for maximum headroom throughout the audio path at any gain setting.
Model 9762 – Dual Combo Owners Manual 6 The Controls 1. +24V Status Indicator This LED indicates +24V power status for each channel. If both channel power LED’s fail to light when the unit is powered on, check to make sure the AC outlet and line cord are working properly, otherwise, check the AC line fuse on the rear panel of the unit. If a channel fails to indicate power status, it is possible the internal thermal fuse has tripped and the unit may require servicing. 2.
Model 9762 – Dual Combo Owners Manual 5. Signal Overload (OL) Indicator This LED indicates signal overload/clipping conditions at the input gain block stages. In normal use the LED should not light or flicker. Reduce the input GAIN switch to lower the input gain and avoid clipping. 6. Output Level VU Meter The five LED’s provide output VU Meter level indication sourced from the line output amplifier at +6, +3, 0, -5 and –10 dB. The “0” LED indicates 0 dB output level referenced to +4 dBm. 7.
Model 9762 – Dual Combo Owners Manual 7 Operation The 9762 is designed for convenience and ease of use. In general you should experiment with a variety of microphones, placements and settings to achieve best results. The 9762 works well with all types of balanced microphones (dynamic and condenser) and is exceptionally suited for use with ribbon type microphones. The preamplifier may be located in the studio control room or in the recording room itself.
Model 9762 – Dual Combo 7.3 Owners Manual Polarity and Impedance Selection The POL polarity switch inverts the polarity (or phase) of the line output transformer. When the POL switch is depressed a relay inverts the line output transformer polarity. Note that the polarity of the unbalanced output is not affected as this signal is sourced prior to the line output transformer. Thus, the polarity of the unbalanced output is always in phase.
Model 9762 – Dual Combo 8 Owners Manual Specifications Recommended Input Impedance: 200 Ω balanced Recommended Output Load: 600 Ω Nominal Line Output Level: +4 dBm into 600 Ω Maximum Input Level: 0 dBu Maximum Output Level (1% THD): +27 dBu bridging or +27 dBm into 600 Ω Maximum Gain: 75 dB Frequency Response: 20 Hz – 50 kHz ±1.5dB Distortion (1 kHz): less than 0.
LIMITED WARRANTY RTZ Audio warrants this product to be free of defects in material and workmanship for a period of 5 years to the original owner. This warranty is enforceable by the original purchaser and is transferable to a subsequent single owner via resale by the current owner. The current owner must provide positive dated proof of the original purchase in the form of the original sales receipt, original canceled check, or other form of positive original proof.
