A-Designs PEQ – 500 Series Passive Equalizer
The A-Designs PEQ is a 500 Series passive equalizer inspired by the iconic Pultec EQP-1A design, offering silky-smooth tone shaping and vintage analog warmth in a compact module.
Designed with custom-wound transformers and all-discrete Class A circuitry, the PEQ brings classic tube-style EQ curves and natural musical response to your modern 500 Series rack — ideal for mixing, mastering, and tracking applications that demand character and detail.
It’s the perfect blend of old-school tonal beauty and modern reliability.
Key Features
- 500 Series passive equalizer modeled after the classic Pultec-style EQ topology.
- Discrete Class A solid-state makeup gain stage for low noise and high headroom.
- Custom Cinemag transformers for analog depth, warmth, and harmonic richness.
- Independent boost and cut controls for both low and high bands — enabling the famous “Pultec trick.”
- Wide, musical curves ideal for mastering and mix bus applications.
- Switchable frequency selections for precise control of lows and highs.
- Transformer-balanced input and output for professional signal integrity.
- Hand-built in the USA using premium-grade components.
Applications
- Vocals: Add smooth air and polish with gentle top-end boosts.
- Mix Bus: Enhance warmth and clarity with wide, natural EQ curves.
- Bass & Kick Drum: Sculpt low frequencies with power and precision.
- Acoustic Instruments: Bring body and shimmer to guitars, pianos, and strings.
Technical Specifications
| Unit Type | 500 Series Passive Equalizer |
|---|---|
| Circuit Type | Passive EQ with Class A discrete solid-state makeup gain |
| Transformers | Custom Cinemag input and output transformers |
| Frequency Bands | Low shelf (boost/cut), high shelf (boost/cut), high cut |
| Low Frequency Selections | 20 Hz, 30 Hz, 60 Hz, 100 Hz |
| High Frequency Boost | 3, 4, 5, 8, 10, 12, 16 kHz |
| High Frequency Attenuation | 5, 10, 20 kHz |
| Boost/Cut Range | Up to ±12 dB per band |
| Input/Output | Transformer-balanced, 500 Series backplane |
| THD + N | < 0.05% @ +20 dBu |
| Power Requirement | Standard 500 Series rack ±16V DC |
| Format | Single-slot 500 Series module |
| Origin | Hand-built in the USA by A-Designs Audio |
Why Choose the A-Designs PEQ?
The A-Designs PEQ delivers the legendary tone-shaping character of vintage passive EQs in a modern, space-saving 500 Series format.
Its combination of silky highs, punchy lows, and transformer saturation makes it perfect for adding analog warmth and dimension to any track or mix.
Whether you’re mastering, mixing, or tracking, the PEQ brings effortless musicality and detail to every source — with the unmistakable A-Designs craftsmanship.