Z&H Designs Hopto Stereo Optical Compressor

The Z&H Designs Hopto Stereo Optical Compressor is a modern, all-discrete optical compressor inspired by the classic LA-2A and LA-3A, refined for contemporary production needs. Built around fully transistorized circuitry, high-voltage discrete op-amps, and a linear power supply, Hopto delivers smooth, transparent compression with a uniquely fast attack option that extends optical compression far beyond its traditional role. The result is a versatile dynamics tool that remains natural and musical while offering greater control over transients.

Key Features

• All-discrete, fully transistorized optical compressor design.
• Inspired by classic LA-2A and LA-3A compression behavior.
• Fast and slow attack modes for expanded transient control.
• Four legendary 990 discrete op-amps.
• High-voltage ±24V linear power supply.
• Effective yet natural optical compression.
• Rich control options for tracking, mixing, and bus processing.

Fast Optical Compression

• Modern opto components enable significantly faster attack times than vintage designs.
• Fast/Slow attack switch allows optical compression to manage sharp transients.
• Capable of controlling guitar pick attack, cymbals, and vocal sibilance without artifacts.
• Compression remains smooth and rounded, even at higher gain reduction levels.
• Ideal for vocals, acoustic instruments, and sources requiring natural dynamic control.

Sidechain & Stereo Operation

• Sidechain high-pass filter options at 100 Hz and 200 Hz.
• Preserves low-end weight on bass, drums, and full mixes.
• Stereo link / mono switch enables linked stereo or dual-mono operation.
• Suitable for tracking, stereo buses, and full-mix compression.

Circuit Design & Sonic Character

• Combination of high-voltage 990 DOA and 123 transformer architecture.
• Delivers transparent, deep, and balanced compression.
• Sound character described as rounded, even, and natural.
• Voiced for the “Zen” side of the Z&H sonic philosophy.
• Excels on vocals while remaining effective across entire mixes.

Build & Workflow

• Dual VU meters for clear visual feedback.
• Make-up gain controls with 21 stepped positions for accurate recall.
• Solid dual-layer front panel with refined metallic finish.
• Handcrafted and individually tested by experienced engineers.

Specifications

• Threshold Range: −30 dBu to +10 dBu, continuously adjustable
• Compression Ratio: Selectable 3:1, 5:1, 10:1
• Maximum Input Level: +24 dBu
• Maximum Output Level: +24 dBu
• Output Gain Control: 0 dBu to +14 dBu, continuously adjustable
• Frequency Response: ±0.5 dB (10 Hz – 20 kHz)
• Noise: < −95 dBu (0 dB gain)
• THD + Noise: 0.005% (1 kHz, +24 dBu, 600 Ω load)
• THD + Noise: 0.01% (1 kHz, +4 dBu, 600 Ω load)
• IMD: 0.008%
• Power Supply: High-voltage linear (±24V)
• Shipping Dimensions (H × W × D): 22.3 × 58.2 × 45.4 cm