Tube-Tech LCA 2B – Dual-Channel Tube VCA Compressor & Limiter

The Tube-Tech LCA 2B is a high-end, all-tube dual-channel Vari Mu compressor/limiter designed for powerful, transparent, and musical dynamic control. Featuring independent compression and limiting for each channel, linkable stereo operation, and Fairchild-inspired time constants, the LCA 2B is a versatile powerhouse for everything from vocals and instruments to bus and parallel compression.

Classic Vari Mu Compression

The Tube VCA (Vari Mu) circuit of the LCA 2B provides a highly musical and flexible compression style, preserving high-end clarity even at extreme settings. With six Fairchild-style attack/release presets and a manual mode, the LCA 2B offers precise control over compression and limiting, making it a go-to unit for studio and live engineers alike.

Key Features

• All-Tube Vari Mu Compression – Rich, warm, and musical dynamic control
• Dual-Channel Design – Independent compression and limiting per channel
• Linkable for Stereo Applications – Seamless stereo bus compression
• Fairchild-Style Time Constants – Six presets plus manual attack/release control
• Powerful Bus Compressor – Perfect for mix bus and parallel compression
• Fast, Smooth Attack – Excellent for drums and percussive elements
• Fully Transformer-Balanced I/O – Ensures pristine audio quality
• Gold-Plated Switches – High durability and signal integrity
• LED Gain Reduction Metering – Easy-to-read visual feedback

Technical Specifications

• Compression Type: Tube VCA (Vari Mu)
• Frequency Response (-3 dB): 5 Hz – 50 kHz
• Noise Level: < -85 dBU at 10 dB gain
• CMRR: > 60 dB at 10 kHz
• Output Gain: -6 dB to +10 dB
• Interconnection: Multiple LCA 2B units can be linked
• Bypass: Clickless In/Out Relay

Compressor Section

• Ratio: 1.6:1 to 20:1 (Variable)
• Threshold: Off to -20 dBU (Variable)
• Attack/Release: Continuously variable
• Fairchild-Style Presets: Six selectable attack/release settings
• Gain Reduction Metering: LED Display

Limiter Section

• Threshold: Off to 0 dBU (Variable)
• Attack: 0.8 ms
• Release: 0.5 sec
• Limiter On/Off Switch
• LED Limiting Indicator

FAQ: LCA 2B Calibration

Since the LCA 2B uses tubes as its VCA, periodic calibration is recommended. Most units operate perfectly for extended periods, but a quick test will determine if calibration is needed.

How to Check Calibration

1. Turn the THRESHOLD for both compressor and limiter fully counterclockwise (CCW).
2. Send a 1 kHz tone at 0 dBU (-4 VU) to the input.
3. Slowly turn the LIMITER THRESHOLD clockwise (CW) until the limiter LED (RED) turns on slightly.
4. If the LED turns on abruptly or oscillates, the unit needs calibration.

Alternatively, if the LCA 2B exhibits excessive “pumping” during audio playback, calibration may be required.

Why Choose the Tube-Tech LCA 2B?

Designed with the Fairchild 670 in mind, the LCA 2B delivers powerful, vintage-inspired compression with the clarity and control needed for modern productions. Whether used for vocals, instruments, drums, or mix bus processing, the LCA 2B remains one of the most versatile and sought-after tube compressors available today.