Z&H Designs ME-250DX Stereo Mastering EQ

The Z&H Designs ME-250DX Stereo Mastering EQ is a mastering-grade evolution of the HVC250, inspired by the legendary Sontec MEP-250 equalizer and refined for modern precision workflows. Featuring stepped controls throughout, ultra-accurate stereo matching, and an onboard analog Mid/Side processor, the ME-250DX delivers transparent, musical equalization with exceptional recallability. Built around all-discrete circuitry and a high-voltage linear power supply, it provides extraordinary resolution, headroom, and control for critical mastering and mix-bus applications.

Key Features

• Mastering version of the HVC250 with stepped controls for precise recall.
• All-discrete analog signal path with high-performance op-amps powered by ±28V rails.
• Ultra-high slew rate exceeding 30V/µs for exceptional transient accuracy.
• Five true parallel fully parametric bands per channel.
• Over 100 selectable frequency points with ultra-fine gain control.
• 0.5 dB gain increments in ±5 dB mode and 1 dB increments in ±10 dB mode.
• Onboard full-analog Mid/Side encoder and decoder.
• Stereo-matched to better than 1% accuracy for mastering applications.
• Independent 56V high-voltage linear power supply for each channel.
• Handcrafted, measured, and verified by experienced engineers before shipment.

Circuit Design & Sonic Character

• All-discrete op-amp architecture using precision 1% components throughout.
• Extremely low distortion and noise floor optimized through extensive PSU and layout design.
• Clean, natural response that remains musical even under aggressive EQ moves.
• Designed for transparency rather than coloration, preserving depth and spatial detail.
• Sontec-inspired response curves optimized for modern mastering demands.

Mid / Side Processing

• Integrated full-analog M/S encoder and decoder using premium THAT components.
• Left channel operates as Mid and right channel as Side in M/S mode.
• Per-channel bypass available in both Stereo and M/S operation.
• Ideal for width control, center focus, and advanced stereo image shaping.

Specifications

• Type: 2-channel, 5-band fully parametric analog equalizer
• Frequency Range: 15 Hz – 25 kHz
• Band Ranges
• LF: 24 Hz – 790 Hz, Q 0.67–4 or shelf, ±10 dB
• LMF: 30 Hz – 8.1 kHz, Q 0.67–4, ±10 dB
• MF: 220 Hz – 8.1 kHz, Q 0.67–4, ±10 dB
• HMF: 490 Hz – 25 kHz, Q 0.67–4, ±10 dB
• HF: 1 kHz – 25 kHz, Q 0.67–4 or shelf, ±10 dB
• Signal-to-Noise Ratio
• Channels Off: Left −98.3 dBu, Right −99.1 dBu
• Channels On (×1): Left −96.8 dBu, Right −97.9 dBu
• Channels On (×2): Left −96.2 dBu, Right −96.9 dBu
• Distortion
• Channels Off: 0.0005%
• Channels On: 0.0013% (20 Hz – 20 kHz)
• Power Supply: Dual independent 56V linear supplies (one per channel)
• Voltage Selector: 110V / 220V
• Chassis Size (H × W × D): 133 × 440 × 282 mm
• Front Panel Size (H × W): 133 × 483 mm