EQ550P | Passive Valve Two Bands Equalizer
- Inspired by Famous Valve Passive EQ
- Hybrid Valve Class A Gain Stage
- Two Band Shelf EQ Design
- Separate Control for Boost and Cut
- 3 Frequency Settings for HF Band
- 3 Frequency Settings for LF Band
- Vintage NOS Discrete Components
- Output Coupled with Custom HRK Transformer
- Class A Output Transformer Driver
- JJ Electronics ECC83 Dual Triode Tube
- On-Board Voltage 500 Rack PSU Filters
- Direct Sale – Save on Distributors Fee!
The EQ550P is a Passive Tube based 2 Band Shelf Equaliser inspired by the famous Pultec design.
Each Band has a separate Boost and Cut Control which allows creating the sophisticated EQ curves.
Each Boost or Cut control has three different and independent frequency settings which give a total of 9 setting combinations per Band.
The Passive filter section changes the EQ curve by attenuating the signal. The ECC83 gain stage restores the signal to the nominal level adding the combination of harmonics and transients.
The EQ550P is very musical and easy to use. It can process any music material, instruments, vocal or recordings, producing amazing results.
The Valve – Discrete Transistors Hybrid circuit is the result of a long development process. It produces real Tube harmonics and reach tone while maintaining the noise on the extremely low level.
Create the Sophisticated EQ Curves!
The unique feature of Passive Equalizer is the ability to Cut and Boost at the same time.
The EQ550P can create the sophisticated EQ curves which cannot be achieved by the active shelf equalizers.
Ability to select three different frequencies independently for Cut and Boost provides countless possibilities in creating custom EQ curves.
Pictures below show a few examples of such EQ curves.
Coupled with Custom HRK Transformers
The Output of the EQ550P is coupled with specially designed custom HRK Transformers. Because of limited space in the 500 module, HRK Custom Transformers became smaller, maintaining no-compromise performance.
All HRK transformers provide the sweet-spot sonic characteristic with pristine detail reproduction. The goal of the design process was to create the transformer which will deliver a balance between the transparency and colouration typical for transformer stages.
Dicrete Transitor Class A Output Transformer Driver
The output transformer is powered by Class A, No-Feedback, DC-Coupled Discrete Driver built with NOS Transistors from ’70s.
Basic Demo Video
Track from the Basic Demo Video:
Kick Drum Demo Video
Track from the Kick Drum Demo Video:
Stereo Demo Video
Track from the Stereo Demo Video:
HF BOOST Frequencies: 6kHz | 10kHz | 16kHz
HF CUT Frequencies: 6kHz | 10kHz | 16kHz
LF BOOST Frequencies: 50Hz | 80Hz | 160Hz
LF CUT Frequencies: 50Hz | 80Hz | 160Hz
EQ Bypassed: 0.024%
EQ Engaged: 0.07% – 0.5% – depending on output level
Headroom / Max Output Level: +15dBu@1% THD
-90dBu – EQ Bypassed
-86dBu – EQ Engaged Flat
Up to 180mA
Compatible with most of the modern 500 Racks.