Universal Audio LA-22 Operations Instructions

Model LA-2ALeveling AmplifierUniversal Audio, Inc.www.uaudio.comPO Box 3818Santa Cruz, CA 95063-3818

5Theory of OperationCompressor BasicsBefore we dig in to a description of the LA-2A circuit, it is useful to examine the generalcharacteristics of com

6As an aside, an expander is a device which increases the dynamic range of a signal. Forexample, a 10dB change in the input signal might result in a

7TRIMIN P U TIN P U TTRA N SFO RM ERO PTIC A LATTEN U A TO RMODULET4VO LTAG EA M P L IF IE R(1 2 A X 7 A )CATHO DEFO LLO W ER(1 2 B H 7 ) PRE-EM PH A

8LA-2A Block DiagramA functional block diagram of the LA-2A is provided in Figure 3. A brief overview of theoperation will be provided here. The inp

9stage. To see why this is true, we can look at the extreme cases. If the resistance isextremely high (this is the case when there is a small input

10The next important aspect is that of the release of the compressor. This is determinedalmost entirely by the characteristics of the photo-cell. Th

11Side-Chain CircuitThe previously described gain reduction circuit is controlled by the control voltage which issupplied by the side-chain circuit.

12previously, the gain reduction is controlled by the photo-cell in the T4 el-op. In order totrack the operation of this cell and determine the gain

13legendary Bill Putnam's company, Studio Electronics Corp shortly before he changed thecompany’s name to UREI®. Three different versions of the

14currently mixing, I'm using both an 1176 and an LA2 on his voice, which is not unusual forme. "The 1176 absolutely adds a bright character

iiTeletronix LA-2A by Universal AudioThank you for purchasing this reproduction of the Teletronix LA-2A. The LA-2A wasoriginally produced in the early

15Ken KessieMixer Ken Kessie (En Vogue, Tony! Toni! Tone!, Celine Dion) is known for beingexperimental. "Seems like everybody knows the basic tri

16inconsistent piece to piece than the 1176s, because of the tubes and the difference infatigue of the tubes."My big mentors were Andy Johns and

iiiIMPORTANT SAFETY INSTRUCTIONSBefore using this unit, be sure to carefully read the applicable items of these operating instructions and thesafety s

ivLA-2A User’s GuideUniversal Audio, Inc.PO Box 3818Santa Cruz, CA 95063-3818(831) 454-0630 voice(831) 454-0689 faxwww.uaudio.comUniversal Audio P

vTable of ContentsTeletronix LA-2A by Universal Audio...iiSpecificatio

1Specifications! Gain Reduction: up to 40 dB! Distortion: less than 0.35% total harmonics at +10 dBm, and less than 0.75% totalharmonics at +16 dBm ou

2Operation of the LA-2AInput and Output ConnectionsInput and Output connections are made using standard XLR style connectors. Terminalstrips are also

3VU Meter OperationThe VU Meter is used for both output level monitoring and gain reduction monitoring.When used to monitor the output level, the user

4CalibrationMeter Zero AdjustThe zero-adjust of the meter is set by the screw-adjust potentiometer located next to theLimit / Compress Switch. To adj