Model 1176AE Anniversary Edition Limiting Amplifier Universal Audio Part Number 65-0010 Revision 1.0 Universal Audio, Inc. Customer Service & Tech Support: 1-877-MY-AUDIO Business, Sales & Marketing: 1-866-UAD-1176 www.uaudio.
Notice This manual provides general information, preparation for use, installation and operating instructions for the Universal Audio 1176AE. 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.
Anniversary Edition This very special, limited-run 1176AE unit is a celebration of Universal Audio’s 10-year anniversary since refounding, fifty years since the original founding of the company, and over 40 years since the original release of the most recognized studio limiter ever made. This hand-built, customized unit is one of only 500–a fitting tribute to the legend that is the 1176, and Bill Putnam Sr.’s amazing audio design legacy. Serial Number Final Assembly by Tested by Universal Audio, Inc.
A Letter From Bill Putnam, Jr. ___________________________________________________________ It is hard to believe that it has been over 40 years since my father first designed the 1176 limiter. One of the characteristics that my father exhibited was a love for new technologies and innovation. I can only imagine my father’s excitement about the potential represented by transistors and semiconductors, which has often been called the most important invention of the 20th century.
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.
Table of Contents __________________________________________________________ A Letter From Bill Putnam, Jr. ............................................................................................. i Important Safety Instructions .............................................................................................. ii Two Page, Two Minute Guide To Getting Started .................................................................... 2 Front Panel .............................................
The Two Page, Two Minute Guide To Getting Started __________________________________________________________ No one likes to read owner’s manuals. We know that. We also know that you know what you’re doing—why else would you have bought our product? So we’re going to try to make this as easy on you as possible. Hence this two-page spread, which we estimate will take you approximately two minutes to read.
The Two Page, Two Minute Guide To Getting Started __________________________________________________________ Step 4: On the right side of the front panel, depress the +4 Meter button. This not only turns on the power to the 1176 but also ensures that the meter displays the final output level. (NOTE: Depressing any Meter button other than OFF also has the effect of powering on the 1176AE; when powered on, the front panel meter lights up.
Front Panel __________________________________________________________ (1) Input - Determines the level of the signal entering the 1176AE, as well as the threshold. Higher settings will therefore result in increased amounts of limiting or compression. (2) Output - Determines the final output level of signal leaving the 1176AE. Once the desired amount of limiting or compression is achieved with the use of the Input control, the Output control can be used to make up any gain lost due to gain reduction.
Front Panel __________________________________________________________ (4) Release - Sets the amount of time it takes the 1176AE to return to its initial (pre-gain reduction) level. The 1176AE release time is adjustable from 50 milliseconds to 1100 milliseconds (1.1 seconds). The release time is fastest when the Release knob is in its fully clockwise position, and is slowest when it is in its fully counterclockwise position.
Front Panel __________________________________________________________ (6) Meter - A standard VU meter that displays either the amount of gain reduction, or output level, depending upon the setting of the Meter Function switch. ( see #7 below) Occasionally, the meter may require calibration.
Rear Panel __________________________________________________________ (1) AC Power Connector / Fuse Holder - Connect a standard, detachable IEC power cable (supplied) here. If fuse replacement is required, use only a 125 mA time delay (slow blow) fuse for operation at 115 V, or a 63 mA time delay (slow blow) fuse for operation at 230 V. Note that the 1176AE has no dedicated on-off Power button; instead, depressing the Meter OFF button ( see #7 on the previous page) has the effect of powering the unit off.
Interconnections __________________________________________________________ (Illustration goes here) (Interconnection illustration—should show 1176AE in standard insert send/return configuration with patch bay, using XLR and, optionally, terminal strip connections) For most applications, we recommend starting with the 1176LN INPUT and OUTPUT knobs set to approximately 24 (their 12 o’clock position) for unity gain.
Insider’s Secrets __________________________________________________________ 1176AE/1176LN-Interhcangeable Tips While there are distinct differences that set 1176AE apart from the 1176LN (the “Bluestripe” program dependency, the “SLO” attack option, and the new ratio array with expanded Multi-Button variations), all of the tips provided in the “Insider’s Secrets” section are certainly interchangeable.
Insider’s Secrets __________________________________________________________ Drums In the world of recording, there’s probably no greater challenge than getting powerful and precise drum sounds. The 1176LN has long been the compressor of choice for engineers for kick drum, snare drum, and overhead or ambient mics. “I’ll always place one big mic, like a U47 (Neumann) or a ribbon mic such as a Coles or Royer, five or six feet in front of the drums,” confides Grammy-winning engineer Jay Newland (Norah Jones).
Insider’s Secrets __________________________________________________________ The 1176LN compression or limiting is heavily program-dependent. That’s an important feature which allows it to be used in a musical, percussive way. Let’s say you have a medium tempo, 4/4 rock beat—an excellent scenario for using “All-Button” mode. In this application, you’d probably have a lot of input level, a slowish attack (so that the transients sneak through), and a quick release. The sonic result is extraordinary.
Insider’s Secrets __________________________________________________________ Controlled Distortion The unique sonic characteristics of the 1176LN make it an effective tone shaper as well. One of its features is ultra-fast attack and release times, and used correctly (or incorrectly, depending on the way you look at it), you can use it to add distortion to any otherwise pristine audio track.
The Technical Stuff __________________________________________________________ History of the 1176LN The original Universal Audio 1176, designed by Bill Putnam, was a major breakthrough in limiter technology – the first true peak limiter with all transistor circuitry offering superior performance and a signature sound. Evolved from the popular Universal Audio 175 and 176 vacuum tube limiters, the 1176 retained the proven qualities of these industry leaders, and set the standard for all limiters to follow.
The Technical Stuff __________________________________________________________ Revision E was introduced in the early 1970s and was the first to accommodate European 220V mains power with a voltage selector on the rear panel. Of all the revisions, model D and model E are considered to have superior sound and are thus the most sought-after versions by audio engineers. Another significant redesign occurred in 1973.
The Technical Stuff __________________________________________________________ Compressor / Limiter Basics The function of a compressor is to automatically reduce the level of peaks in an audio signal so that the overall dynamic range—that is, the difference between the loudest sections and the softest ones—is reduced, or compressed, thus making it easier to hear every nuance of the music.
The Technical Stuff __________________________________________________________ Input Signal and Threshold The first and perhaps most significant factor in compression is the level of the input signal. Large (loud) input signals result in more gain reduction, while smaller (softer) input signals result in less gain reduction. Threshold is another important factor. It is a term used to describe the level at which a compressor starts to work.
The Technical Stuff __________________________________________________________ Knee A compressor's knee determines whether the device will reach maximum gain reduction quickly or slowly. A gradual transition (“soft knee”) from no response to full gain reduction will provide a gentler, smoother sound, while a more rapid transition (“hard knee”) will give an abrupt “slam” to the signal.
The Technical Stuff __________________________________________________________ Output (Makeup Gain) Finally, an output control is employed to make up for the gain reduction applied by the gain reduction circuitry; on the 1176LN, this is the function of the Output knob.
The Technical Stuff __________________________________________________________ To make such a cable, first acquire the following components: (1) Female XLR cable connector (1) Male XLR cable connector (1) 1/4" TRS cable connector A suitable length of light gauge unbalanced microphone cable A short piece of 22 gauge bus wire Then follow these steps to assemble the cable: 1. Cut two lengths of audio cable suitable to reach from the 1176LN to the insert point on your mixer.
The Technical Stuff __________________________________________________________ Terminal Strip Connections Because it predated standard XLR connectors, the original 1176AE provided terminal strips for input and output line-level connections, and so that feature has been retained here (in addition to providing a modern XLR input and output).
The Technical Stuff __________________________________________________________ Maintenance Information Calibrations There are no user serviceable parts inside the 1176AE. Unit calibration as well as repair should only be performed only by qualified service personnel. These calibration procedures are provided only for use by qualified service technicians. Zero Set The 1176AE meter may occasionally need to be calibrated.
The Technical Stuff _______________________________________________________________________ The following procedure is used to set “Q” bias: 1. Select either +4 or +8 output metering. 2. Adjust R59 fully counterclockwise (CCW). 3. Apply a sine wave signal to the 1176AE. 4. Adjust the Input and Output controls for 0dB output. 5. Slowly adjust R59 CW until the output decreases by 1.0 dB. Meter Driver Null A multimeter is needed to perform this calibration procedure: 1.
The Technical Stuff __________________________________________________________ Use the following procedure to calibrate the 1176SA stereo adapter: 1. Remove the signals from both 1176AE units. 2. Disable gain reduction on each 1176AE by setting both Attack controls fully counterclockwise. 3. Using two cables with RCA connectors on both ends, connect the 1176-SA to both 1176AEs. 4. Depress the Meter GR pushbutton. 5. Adjust the potentiometer on the 1176-SA until both meters read 0dB.
The Technical Stuff __________________________________________________________ 1176LN Circuit Details The fundamental problem facing Bill Putnam Sr. when he began designing the 1176 limiter was how to keep its FET operating within its linear region in order to keep distortion sufficiently low.
The Technical Stuff __________________________________________________________ Input Section Figure 2 - Input Section As shown in Figure 2, the 1176LN input section is comprised of an adjustable passive attenuator followed by a transformer. The purpose of this section is to reduce the signal level so as not to overdrive the FET based gain reduction stage. Additionally, the adjustable input level is used to control the amount of compression. This input circuit was used in Revisions A-F.
The Technical Stuff __________________________________________________________ voltage applied to its gate. The higher the voltage applied to the gate, the smaller the drain-source resistance will be. Figure 4 - Using an FET as a voltage-variable resistor. The combination of R5 and Q1 acts as a voltage divider which controls the gain. Figure 4 shows how the FET’s resistance determines the gain of this section. Resistor R5 and the FET essentially comprise a voltage divider circuit.
The Technical Stuff __________________________________________________________ Output Amplifier The output amplifier is a Darlington pair followed by a class A stage based on a 2N3053 transistor. The 1176LN output stage was essentially the same as the Universal Audio 1108 pre-amplifier. The output transformer is a custom transformer designed by Bill Putnam Sr. Aside from offering output impedance matching, the transformer forms an integral part of the feedback network used to stabilize the output stage.
The Technical Stuff __________________________________________________________ A bias level is applied to the diodes by the Compression Ratio pushbutton switches. This controls the threshold of limiting, and is adjusted for the correct value as determined by the currently selected compression ratio selection. R55 controls the compressor’s attack time by regulating how fast C22 is charged. Likewise, R56 determines the compressor’s release time by controlling the rate at which C22 discharges.
Glossary of Terms __________________________________________________________ Ambient noise - Low-level noise created by environmental factors such as fans, air conditioners, heaters, wind noise, etc. Attack time - Describes the amount of time it takes compressor circuitry to react to and reduce the gain of incoming signal. A compressor set to a fast attack time kicks in almost immediately and catches transient signals of very brief duration, reducing their level and thus "softening" the sound.
Glossary of Terms __________________________________________________________ dBm - Short for “decibels as referenced to milliwatt,” dissipated in a standard load of 600 ohms. 1 dBm into 600 ohms results in 0.775 volts RMS. dBV - Short for “decibels as referenced to voltage,” without regard for impedance; thus, one volt equals one dBV. Dynamic range - The difference between the loudest sections of a piece of music and the softest ones.
Glossary of Terms _______________________________________________________________________ Peak reduction - A synonym for compression or limiting. Program dependent - Refers to a parameter that varies according to the characteristics of the incoming signal. The amount of 1176LN/1176AE gain reduction is program dependent. Ratio - see “Compression Ratio” Release time - The time it takes for a signal to return to its initial (pre-compressed) level.
Recall Sheet __________________________________________________________ - 32 -
Specifications _______________________________________________________________________ Input Impedance 600 , bridged T-control (floating) Output Load Impedance 600 (floating) Frequency Response 20 Hz to 20 kHz ± 1 dB Gain 45 dB, ± 1 dB Distortion > 0.5% T.H.D. from 50 Hz – 15 kHz with limiting, at 1.1 seconds release setting. Output of +22 dBm with no greater than 0.5% T.H.D.
Additional Resources/Product Registration/Warranty/Service & Support __________________________________________________________ Additional Resources We’ve got a pretty cool website, if we may say so ourselves. Check us out at http://www.uaudio.com.
