Universal Audio 2-1176 manuel d'utilisation

Model 2-1176 Dual 1176LN Limiting Amplifier Universa l Audio P art Num ber 65- 00047 Universal Audio, Inc. Customer Service & Tech Support: 1-877-MY-AUDIO Business, Sales & Marketing: 1-866-440-1176 www.uaudio.com[...]

- i - Notice This manual provides general information, preparation for use, installation and operating instructions for the Universal Audio 2-1176. 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[...]

A Letter From Bil l Putnam, Jr. ___________________________________________________________ - ii - Thank you for purchasing the 2-1176 Dual 1176LN Limiting Amplifier. My father designed the original 1176 back in 1966, and he was very pleased with his accomplishment. He was equally gratified by its reception by his peers in both the recording and br[...]

Importa nt Safet y Instruc tions ___________________________________________________________ - iii - Befo re u sing thi s un it, b e su re t o ca refu lly r ead the app lica ble item s o f the se o per atin g in stru ctio ns a nd t he safe ty s ugg estio ns. Afte rwa rds, kee p th em han dy f or fu ture ref eren ce. Tak e sp ecia l ca re to fol low[...]

Table of Content s __________________________________________________________ - 1 - A Letter From Bill Putnam, Jr. ................................................................................................................ Important Safety Instructions ............................................................................................[...]

The Two Page, Tw o Minute Guide To Getting S tarted __________________________________________________________ - 2 - 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 s[...]

The Two Page, Tw o Minute Guide To Getting Started __________________________________________________________ - 3 - Step 7: Set the Attack and Release knobs for both channels fully counterclockwise (to their SLOW position). Step 8: Set the Ratio knobs for both channels to their 4 position, thus selecting moderate compression (at a 4:1 ratio) for bo[...]

Front Pa nel __________________________________________________________ - 4 - NOTE: The 2-1176 provides two channels, each of which have identical front panel controls. (1) Attack - Sets the amount of time it takes the 2-1176 channel to respond to an incoming signal and begin gain reduction. The 2-1176 attack time is adjustable from 20 microseconds[...]

Front Pa nel __________________________________________________________ - 5 - (4) Meter - A standard VU meter that displays either the amount of gain reduction or output level for the channel, depending upon the setting of the Meter Function switch. (  see #3 above ) Occasionally, one or both meters may require calibration. (  see page 23 for[...]

Front Pa nel __________________________________________________________ - 6 - (8) LINK / DUAL switch - Sets the 2-1176 to either dual mono or stereo linked operation. When set to the down (DUAL) position, the 2-1176 operates as two separate compressors, with the two channels operating completely independent of one another. When set to the up (LINK)[...]

Rear Pa nel __________________________________________________________ - 7 - NOTE: The 2-1176 provides two channels, each of which have identical rear panel controls. (1) Line INPUT - Connect line-level input signal for each channel to these balanced XLR connectors. Pin 2 is wired positive (hot). This signal will normally be arriving via a patchbay[...]

Interco nnections __________________________________________________________ - 8 -[...]

Insider’s Secrets __________________________________________________________ - 9 - Whatever you can do with an 1176LN, you can do with a 2-1176... two times over. In addition, Link mode allows the 2-1176 to process not just monophonic signals, but stereo signals such as drum or backing vocal submixes. You can even strap the 2-1176 across the ster[...]

Insider’s Secrets __________________________________________________________ - 10 - Jim Scott, who won a Grammy for Best Engineered Album for Tom Petty’s Wildflowers , adds, “I use 1176s real conservatively and they still do amazing things. I always use them on vocals.... I’m always on the 4:1 [ratio], and the Dr. Pepper [Attack/Release set[...]

Insider’s Secrets __________________________________________________________ - 11 - “When I am mixing,” Johns adds, “I mult the bass drum and the snare. The bass drum will not be even, so the first bass drum track—the one that doesn’t have the 1176 on it—gets to breathe. Then I put another bass drum next to it with an 1176 at a 4:1 [r[...]

Insider’s Secrets __________________________________________________________ - 12 - “Treating some electric guitar sounds that had been previously recorded,” Curwin added, “allowed the opportunity of experimenting with the different ratios and the attack and release controls, and with careful positioning it was possible to give the guitar a[...]

Insider’s Secrets __________________________________________________________ - 13 - Controlled Distortion The unique sonic characteristics of the 2-1176 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 a[...]

Insider’s Secrets __________________________________________________________ - 14 - mode. Adding a bit of slam-compressed audio to the mix produced a brighter mix without high- frequency overload. It also really helped both drums and guitars maintain a strong place in the mix without overwhelming vocals and bass. For even more control, I also hoo[...]

The Tech nical St uff __________________________________________________________ - 15 - History o f the 11 76 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 p[...]

The Tech nical St uff __________________________________________________________ - 16 - Another significant redesign occurred in 1973. The revision F output stage was modified to provide higher output current capability by using a push-pull circuit design borrowed from Universal Audio's new 1109 preamplifier. This new output stage replaced the[...]

The Tech nical Stu ff __________________________________________________________ - 17 - Compre ssor / Lim iter Basi cs 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[...]

The Tech nical St uff __________________________________________________________ - 18 - 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 a[...]

The Tech nical St uff __________________________________________________________ - 19 - maximum value. At very high ratios of 20:1 or greater (some limiters even offer a theoretical infinite ratio of Infinity:1), “brick wall” limiting kicks in—that is, almost any change in input, no matter how great, results in virtually no increase in output[...]

The Tech nical St uff __________________________________________________________ - 20 - Output (Makeup Gain) Finally, output controls are employed to make up for the gain reduction applied by the gain reduction circuitry; on the 2-1176, this is the function of each channel’s Output knob. Makeup gain is generally set so that the compressed signal [...]

The Tech nical St uff _______________________________________________________________________ - 21 - 1. While in Link mode, send stereo signal to the 2-1176 but monitor the left channel only. 2. In the left channel of the 2-1176 only, set the Ratio switch as desired and adjust the Input and Output knobs until the desired amount of compression or li[...]

The Tech nical St uff __________________________________________________________ - 22 - 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 follo[...]

The Tech nical St uff __________________________________________________________ - 23 - Mainten ance In formatio n Meter Calibration The 2-1176 meters may occasionally need to be calibrated. This is accomplished by adjusting the Zero Set potentiometer, located through a small hole on the front panel between each channel’s Input and Output knobs. [...]

The Tech nical Stu ff __________________________________________________________ - 24 - Changing Fuses The AC power fuse is located on the power supply circuit board inside the 2-1176, directly behind the AC power connector, accessed by removing the top panel of the 2-1176. Always remove the power cord before checking or changing the fuse! The requ[...]

The Tech nical St uff __________________________________________________________ - 25 - 2-1176 C ircuit De tails 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. After much experimentation he eventually hit[...]

The Tech nical St uff __________________________________________________________ - 26 - Input Section Figure 2 - Input Section As shown in Figure 2, the 1176 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 re[...]

The Tech nical St uff __________________________________________________________ - 27 - As shown in Figure 3, gain reduction is achieved by a Field Effect Transistor (FET) which is used as a variable resistor. In the 1176, the FET acts like a resistor whose resistance is controlled by the voltage applied to its gate. The higher the voltage applied [...]

The Tech nical St uff __________________________________________________________ - 28 - Output Amplifier The output amplifier is a Darlington pair followed by a class A stage based on a 2N3053 transistor. The 1176 output stage was essentially the same as the Universal Audio 1108 pre-amplifier. The output transformer is a custom transformer designed[...]

The Tech nical St uff __________________________________________________________ - 29 - As shown in Figure 5, this circuit controls the amount of compression as well as the attack and release times of the limiter. The input to this circuit is taken from the output of the preamplifier section, just before the volume control potentiometer (R23). The [...]

Glossary of Terms __________________________________________________________ - 30 - 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 t[...]

Glossary of Terms __________________________________________________________ - 31 - 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[...]

Glossary of Terms _______________________________________________________________________ - 32 - Peak reduction - A synonym for compression or limiting. Program dependent - Refers to a parameter that varies according to the characteristics of the incoming signal. To some degree, the amount of 2-1176 gain reduction is program dependent. Ratio - see [...]

Recall S heet __________________________________________________________ - 33 -[...]

Specific ations _______________________________________________________________________ - 34 - Input Impedance 15 k Ω , 600 Ω selectable Output Load Impedance 600 Ω (floating) Frequency Response 20 Hz to 20 kHz ± 1 dB Gain 40 dB, ± 1 dB Distortion > 0.5% T.H.D. from 50 Hz – 15 kHz with limiting, at 1.1 seconds release setting. Output o[...]

Addition al Resou rces/Pro duct Re gistration/W arranty/ Service & Suppo rt __________________________________________________________ - 35 - Addition al Resou rces We’ve got a pretty cool website, if we may say so ourselves. Check us out at http://www.uaudio.com. There, you’ll find tons of information about our full line of products, as we[...]