Pultec Equalizer Schematics
This assumption was made after analyzing original Pultec EQ schematic. The HRK EQ550P is a pure shelf EQ and it has no provision for Q factor adjustment and no inductors. No limitation in HF band is added and the HF response continues up to 120kHz where it starts to slope down naturally. Schematics, transformer and inductor datasheets, manual documentation included Email and/or telephone tech support RecProAudio Completely Assembled Pultec EQ KIT: $2545 Completely assembled RPA EQP-1a kit, hand-wired by Ron (cayocosta), point-to-point, tested, ready to use.
DIYRE EQP5 Passive Equalizer vs EQ550P Valve Passive Equalizer – Comparison Page The DIYRE EQP5 and the HRK EQ550P are the passive Pultec inspired equalizers. This page compares the main features and highlights the difference between both units. This page should be treated as the guide for the website visitors and the FAQ section.
The main features of the DIYRE EQP5 and the HRK EQ550P colour mic preamps are presented and compared in the table below. FEATURE DIYRE EQP5 HRK EQ550P Number of Bands 2 2 Frequencies HF Band 10kHz / 16kHz (20kHz) 6kHz / 10kHz / 16kHz Frequencies LF Band 60Hz / 30Hz 50Hz / 80Hz / 160Hz EQ Filters Type Capacitors + 1 Inductor Capacitors Only Adjustable Q YES (PCB Trimmer) NO Gain Stage Type Integrated Circuit (IC) Opamp OR Discrete Opamp Discrete Class A Circuitry with ECC83 Vacuum Tube Output Stage Electronic Balanced (IC) OR Transformer Class A Discrete Driver + Transformer Input Stage Electronic Balanced Electronic Balanced The DIYRE EQP5 and the HRK EQ550P share the same topology of the equalizer section. Each Band consist the independent Boost and Cut knob for HF and LF section, which makes four knobs in total.
The frequencies for each band can be selected individually for Cut or Boost knobs. This creates a lot of options for creating custom EQ curves. The DIYRE EQP5 has two frequencies which can be selected for each Boost or Cut knob, while the HRK EQ550P has three frequencies to choose from for each Boost or Cut knob.
Ez macros 5 1 keygenguru legit. The Filter Type. Although both units are inspired by the famous Pultec EQ, there are some differences between the EQ filter design. It seems that the DIYRE EQP5 follows more accurately the original design and provides the adjustable Q option with PCB trimmer. Furthermore, the filter section consists the single inductor which suggests that the HF response might be limited above 20kHz depending on Q setting. This assumption was made after analyzing original Pultec EQ schematic. The HRK EQ550P is a pure shelf EQ and it has no provision for Q factor adjustment and no inductors.
No limitation in HF band is added and the HF response continues up to 120kHz where it starts to slope down naturally. Such design of the circuit is optimised for Air frequencies and harmonics which are produced by the ECC83 valve and the output transformer. The Gain Stage and the Output Stage. The passive EQ filter section needs the gain stage to work properly.