Model 2-610 Dual Channel Tube Preamplifier Universal Audio Part Number 65-0008 Revision 1.
The 2-610 Dual Channel Tube Preamplifier Thank you for purchasing the 2-610 Dual Tube Microphone Preamplifier. The 2-610 is inspired by the microphone preamp section of the 610 console designed by my father, M.T. “Bill” Putnam, in 1960. The 610 was a rotary-control console and was the first console of a modular design. Although technologically simple compared to modern consoles, the 610 possessed a warmth and character that kept it in demand for decades.
IMPORTANT SAFETY INSTRUCTIONS Before using this unit, be sure to carefully read the applicable items of these operating instructions and the safety suggestions. Afterwards keep them handy for future reference. Take special care to follow the warnings indicated on the unit, as well as in the operating instructions. 1. Water and Moisture – Do not use the unit near any source of water or in excessively moist environments. 2.
Notice This manual provides general information, preparation for use, installation and operating instruction for the Universal Audio 2-610 Microphone Preamplifier. The information contained in this manual is subject to change without notice. Universal Audio, Inc. makes no warranties of any kind with regard to this manual, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Universal Audio, Inc.
Table of Contents Performance and Audio Specifications................................................................................................................ 1 Preamp Operation Instructions .......................................................................................................................... 2 2-610 Front Panel................................................................................................................................................ 2 Input Select ...........
2-610 Specifications Microphone Input Impedance Selectable, 500 or 2k Balanced Line Input Impedance 13.8 k Hi-Z Input Impedance Selectable between 2.2 M or 47 k Maximum Microphone Input Level +3.
Preamp Operating Instructions The 2-610 is a two-channel, vacuum-tube microphone/instrument/line preamplifier. Each channel has two gain stages that each utilizes a dual-triode tube operating in a class A single-ended configuration. Variable negative feedback is applied to both of these stages to control gain, distortion, and frequency response. Balanced inputs and outputs are transformer coupled.
Input Select The input select switch determines which input is active: Mic, Line, or Hi-Z. Both the Mic and Hi-Z inputs include two settings to select between unique input impedances. Mic Selects the signal input from the balanced rear panel MIC INPUT connection. The impedance for the MIC INPUT can be set to 500 or 2.0K . Switching between these two positions while listening to a connected microphone may reveal a different tonal quality and/or gain difference.
-15 dB PAD Reduces the input signal by -15dB; Recommended in reducing the incoming signal in cases where undesired distortion is present at low gain levels. Polarity The front panel toggle switch labeled IN ø and OUT ø determines the polarity of the LINE OUTPUT. When IN ø is selected, pin 2 is hot (positive). When OUT ø is selected, pin 3 is hot (positive). Polarity reversal may be useful in cases where more than one microphone is utilized in recording a source.
Power The 2-610 provides the user with a front panel power switch. It is recommended to power off the unit when the 2-610 is not used for extended periods of time. 2-610 Rear Panel The rear panel (figure 3) has two identical channels each with MIC INPUT, LINE INPUT, and LINE OUTPUT XLR connectors. The center of the rear panel has an AC Power input with a fuse holder and a voltage selector switch. These connectors and controls are discussed in the following sections.
AC Power The 2-610 uses a standard, detachable IEC power cable. Internal Voltage Selector The 2-610 can operate at 115V or 230V. To change the mode, wait 5 minutes after power down, unplug the AC power cord from the rear chassis. Remove the top cover. As shown below, there is a connector that can be plugged in to one location or another location to configure the unit for 115V or 230V operation. This figure shows the unit configured for 230V operation.
Block Diagram Wally Heider’s Remote Recording Van 7
Historical Notes Bill Putnam Sr. was awarded the 2000 Technical Grammy for his multiple contributions to the recording industry. He was highly regarded as a recording engineer, studio designer/operator and inventor. Putnam was considered a favorite of musical icons including Frank Sinatra, Nat King Cole, Ray Charles, Duke Ellington, Ella Fitzgerald and many, many more.
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