Z&H Designs HO2 All-Discrete 2-Channel Mic Preamp

The Z&H Designs HO2 All-Discrete 2-Channel Mic Preamp delivers mastering-grade clarity with the flexibility to introduce harmonics and color when a track calls for more attitude. Built as a two-channel companion to the HO8, HO2 combines an all-discrete signal path, high-voltage discrete op-amps, and a 56V linear power supply to provide up to 75 dB of gain with a linear response and consistent performance. With DI capability, a selectable permalloy output transformer, and comprehensive per-channel utilities, HO2 is designed for studios that need pristine capture, repeatable control, and tasteful character on demand.

Key Features

• All-discrete, high-voltage 2-channel microphone preamp.
• Six high-voltage discrete op-amps for extended bandwidth and dynamic range.
• Up to 75 dB of mic gain in 5 dB stepped increments.
• Linear trim-matching control with ±5 dB range for fine adjustment and character shaping.
• DI input capability for electric guitar, bass, and other instruments.
• Selectable permalloy output transformer for added harmonics and coloration.
• Per-channel 48V, pad, polarity invert, and 3-level low cut.
• Neon dB metering and curved anodized front panel.

Circuit Design & Sonic Character

• All-discrete signal path designed for clean, vivid capture on piano, vocals, acoustic guitar, and strings.
• Z&H “Zen Core” architecture inspired by modern high-headroom recording philosophies.
• Designed to remain transparent at high gain levels while retaining musical solidity.
• Trim-matching control supports subtle saturation and tonal variation when pushed.
• Permalloy output transformer expands harmonic texture and color options beyond HO8-style voicing.
• Voiced to cover both “Zen” (clean) and “Hit” (character) workflows.

Utilities & Workflow

• Stepped gain control in 5 dB increments for fast recall.
• Linear trim-matching control in a flexible 10 dB interval for fine gain staging.
• Per-channel DI input switching for instrument tracking workflows.
• Per-channel 48V phantom power, pad, polarity invert, and 3-level low cut.
• Designed for modern session work from singer-songwriter recording to ensemble and orchestral tracking.

Power & Build Quality

• 56V high-voltage linear power supply for increased headroom and reduced noise.
• Optimized layout and power design for consistent distortion behavior and low noise floor.
• Handcrafted construction with final verification by experienced engineers prior to shipment.

Specifications

• Channels: 2
• Gain Range (Mic Input): 10–75 dB
• Z&H Trim Range: −5 dB to +5 dB
• Maximum Output Level: +26.5 dBu (100 kΩ load, 0.1% THD)
• VU / LED Meter Green Threshold: −14 dBu
• VU / LED Meter Red Threshold: +24 dBu
• Distortion & Noise
• THD+N @ 20 dB Gain, +20 dBu Out: <0.005%
• THD+N @ 40 dB Gain, +20 dBu Out: <0.008%
• THD+N @ 60 dB Gain, +20 dBu Out: <0.048%
• Intermodulation Distortion (IMD): <0.021%
• Equivalent Input Noise (EIN, 200 kΩ Source): <−95 dB
• Equivalent Input Noise (EIN, 600 Ω Source): <−95 dB
• Performance
• CMRR: 41.4 dB at 400 Hz, 1 kHz, and 10 kHz
• Phase Deviation (HPF Off): >4° from 50 Hz to 25 kHz
• Frequency Response (−3 dB): 4.5 Hz – 390 kHz (Mic Input @ 40 dB Gain)
• Frequency Response (−0.5 dB): 10.5 Hz – 140 kHz (Mic Input @ 40 dB Gain)
• Impedance
• Mic Input Impedance: 1.7 kΩ
• Ribbon Mode Input Impedance: 1.2 kΩ
• Balanced Output Impedance: 600 Ω
• Unbalanced Output Impedance: 400 Ω
• Physical & Power
• Dimensions (H × W × D): 4.3 × 44 × 26 cm
• Weight: 4.8 kg (10.58 lb)
• Power Consumption: 100–240 V AC, 50 W max