L-23: Valve Microphone Preamplifier and Compressor
Release date: To Be Determined
Proprietary input transformer, dual valve stages operating at 270V dc in a pentode configuration, proprietary output transformer
The compressor circuit has the gain reduction characteristics of an LA-2, but uses an opto-coupled (more like the LA-4) control circuit that introduces RMS level averaging. Available compression ratios are 2:1, 4:1, 7:1 and 10:1.
The L-21 provides control over input level with its -20db pad, optimal for use in a console insert.
The L-21 also provides the same Hi-Pass filters as the L-21, with settings of 40Hz and 70Hz, with a more gentle slope. 48v phantom power, and a phase reversal switch is there as well. The design characteristics include regulated power on board, insuring repeatable performance.
The circuit provides makeup gain is added automatically. Final output level is determined by the output and gain reduction controls.
The Gain Reduction potentiometer for threshold is provided, as well as a fully calibrated VU meter that shows either input or gain reduction. An additional benefit is the ability to link two channels of the L-21 for stereo use! See the 6 space lunchbox for more details!
The line level input capability of the MX-3 means that this unit can pull double duty acting as the preamplifier on the way in and an excellent master buss compressor during mix down.
The output line drivers on this unit exceed 32dBm before clipping into line (low impedance) level, making the units and excellent final stage line driver for live sound venues as well.
* The L-23 requires an additional voltage. Your rack can be modified, or VSI makes a 10 space rack and a 6 space lunchbox to accommodate the M-3 power requirements. The MX-1 and MX-1A are fully API™ 500 compatible.
