The LA502 is a soft knee, electro-optical compressor based on the LA2A/LA3A design, which we have adapted to the '500' series format.

It delivers the vintage compression and warmth of its ancestor thanks to the optical coupler response, side chain and transformers.

It shines on vocals, bass and drums.

The LA502 adds a few features to the original such as a new ratio of 6, two high-pass filter in the side chain and two slower attacks of 10 and 20 ms.

Install it in your API* compatible Lunchbox^TM rack and start working.

Highlights

• Based on the LA2A/LA3A compressor,
• Transformers on input and output,
• Extremely simple to use, never sounds bad,
• True RMS compression,
• Program dependent attack, release and ratio makes it very transparent sounding,
• More than 40dB of gain reduction,
• 3 ratios : 3 (LA2A Compress), 20 (LA2A Limit) and one additional ratio 6.
• Optional High pass filter in the sidechain @100 & 200 Hz,
• 3 Attack times : 5mS (LA2A), 10mS and 20mS,
• Can be linked for stereo,
• Hardware relay bypass,
• Available assembled or as a full kit.

1: PEAK Sets the amount of compression from zero to more than 40 dB of gain reduction. It defines the threshold at which the compression appears.

2: RATIO 3 positions switch that set the compression ratio.

• Ratio 3 (left): This is the COMPRESS setting in the LA2A. The actual ratio value is program dependent and changes with the level.
• Ratio 20 (center): This is the LIMIT setting in the LA2A. With this setting the LA502 works like a limiter.
• Ratio 6 (right): This is an additional intermediary setting.

3: HPF This switch inserts a high-pass filter in the sidechain which produces a fat sound and eliminates bass driven pumping.

• 0 (left): No filter, works like the original LA2A,
• 100Hz (center): 100Hz high pass,
• 200Hz (right): 200Hz high pass.

4: ATTK Sets the attack time of the compressor.

• 5mS (left): This is the attack time of the LA2A.
• 10mS (center): We have added a delay in the sidechain allowing percussive sound to pass through less affected.
• 20mS (right): The delay is further increased.

5: BYP

• BYP (left): Hardware relay bypass,
• IN (center): Compressor active,
• STER. (right): Compressor active and stereo link connected for stereo operations.

6: GAIN This potentiometer sets the output level of the compressor.

7: Meter Shows the gain reduction from -3dB to -20dB.

What's in the kit?

Absolutely everything!

• Passive components (resistors, capacitors, inductors),
• Transformers
• Active components (diodes, transistors, LED's, Opto-coupler, IC's),
• Control elements (switches, potentiometers, knobs),
• Connectors, relay,
• PCB's,
• Front panel and side panel,
• All hardware.

You bring the solder (use good quality solder, 1mm diameter max) and the Lunchbox.

Difficulty level

The LA502 kit is an easy kit. It can be undertaken by everyone who is able to make a clean solder joint.

The setup is simple. It only requires a decent quality AC voltmeter.