LA Audio Classic Compressor

Two channel compressor

Review by George Shilling

There are currently available many compressors and other outboard devices which use vacuum tubes and which have fairly hefty price tags. Some of these units have a limited range of useful features, and many lack the qualities of vintage valve designs. It was therefore a breath of fresh air to encounter the LA Audio Classic Compressor, which aims to emulate vintage equipment, but without the valves and large price tag of some other currently available units.

The LA Audio Classic Compressor is a 2U two-channel compressor which uses discrete FET gain control devices (rather than proprietary VCA ICs) in an effort to emulate the sound of Urei, dbx and Fairchild compressors. Suggested uses are for vocals and across the whole mix. The unit has been available for some time already, but has recently gained an optional extra, included in the review model. This is an A to D converter, allowing direct connection to a digital console, multitrack or mastering machine such as a DAT recorder.

The unit has a sturdy, professional feel to it, with a no-nonsense grey painted front panel, featuring black plastic pots and switches. These all worked well, although the actual knobs felt a little cheap. There are pots for Input Gain (useful, with centre détente and input clip LEDs), Threshold, Attack, Release and Output Gain. The Ratio control has six positions: soft knee at 1.5, 2, 3 and 5; hard knee at 10 and 20. Each channel has a relay bypass switch with LED, a DS switch which adds a sibilance filter sidechain, and also a meter select switch to display either Gain Reduction or Output Level. There is additionally a Stereo Link switch which disables some of Channel 2's controls. The VU meters are large and clear, but they have no external trim adjustment. Between them are two red LEDs which light up a couple of dBs before overload of the A to D output. This is useful as a warning and generally any serious attempt to optimise the digital level will have to be achieved using meters on the device connected to the digital output. The front panel also sensibly sports a Power switch with an LED. When you switch on, there is a short delay before the relays close and connect the outputs.

The back panel features Inputs and Outputs on standard XLR connectors, with Side Chain Send and Return jack sockets for each channel. There is a switch for +4dB and -10dB switching. The mains lead connects to a standard IEC socket. A small panel contains the A to D converter. There are standard sockets for S/PDIF (phono), Optical EIAJ and AES/EBU (XLR) formats, along with a set of tiny DIP switches for setting format and sampling rate. These are a little inconvenient, especially mounted on the back panel. However, in most set-ups they will be set, then left in the same position. Unfortunately, although there is a switch marked Int/Ext there is not yet a way of setting the converter to an external clock, which may be a limitation for certain applications.

The manual for the converter is somewhat preliminary, and hints that this feature may be implemented in the future. I couldn't help wondering if the R & D department are working on a D to A converter, for future inclusion of a digital input.

In use it was possible to get fairly close to the sound of a Urei 1176 or 1178 and by setting the appropriate attack and release you can emulate something like the compression of a dbx 165. However, with no auto attack and release settings the variable characteristics of the often used dbx auto mode are not really attainable. Having said that, the overall character of the compression more closely resembles the more severe dbx than the Urei. The Attack and Release settings covered a wide range, and in fact it was easy to set the Release too fast giving a distorted sound. I also thought that it was somewhat rash of the manual to claim that the unit could emulate a Fairchild. When you consider that a Fairchild 670 was recently advertised for sale for £12,500 (UKP), then it is not really surprising that a unit costing just over one twentieth of that does not quite have the same magic! Generally though, I found the quality of the unit to be very high, and I would be happy to use this unit for certain applications, especially bass guitar, or across the mix (depending on program).

The manual is clear and helpful, even explaining the principles of compression for the inexperienced. The digital out option will certainly appeal to many especially at the competitive price for which SCV are marketing the board. The XLR-only analogue inputs and outputs may put off some semi-professional or home studio users, but I would have no hesitation in recommending this unit as a very good value, high quality unit.

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