EQP-1A / Legendary Tube-EQ
That Classic
Tube EQ Sound!
Boost it, cut it, hear the magic.
A legendary tube EQ. We painstakingly recorded a REAL vintage Pultec EQP-1A and rebuilt it as a VST with advanced circuit modeling. Every detail was measured and matched to the original hardware to deliver that unmistakable classic tube EQ character — completely free.
Free · VST3 · AU · Standalone · macOS + Windows
The capture
Feels like
the real thing
We didn't just model an EQ curve. We captured how the hardware behaves. Every knob, every switch, every boost and attenuation setting went through a real vintage unit and was analyzed to reproduce the original's character. Advanced circuit modeling turned those measurements into a detailed digital model that captures not just the frequency response, but the subtle imperfections that make the hardware so desirable.
Low frequency
- CPS
- 20 · 30 · 60 · 100 Hz
- Boost
- Shelf, 0 to 13.5 dB
- Atten
- Shelf, 0 to 17.5 dB
High frequency
- KCS
- 3 · 4 · 5 · 8 · 10 · 12 · 16 kHz
- Boost
- Peak, 0 to 18 dB
- Bandwidth
- Sharp to broad
High atten
- Atten sel
- 5 · 10 · 20 kHz
- Atten
- Shelf, 0 to 16 dB
In and lamp
- In
- The EQ network in or out
- Lamp
- Lit by your signal, 25 ms up, 180 ms down
- Preset
- Factory and your own
Accurate advanced modeling
Mapped
sweep by sweep
To capture the original unit, we ran extensive frequency sweeps through the hardware at every stage of the signal path. From the deepest lows to the top of the audible range, each sweep mapped exactly how the circuit responds, not just at flat settings but across all kinds of boost, attenuation, bandwidth and frequency combinations.
Instead of guessing the response between a handful of points, the model is fitted to the real machine and rebuilds its response live as you turn the knobs. The result is an EQ that reacts like the hardware, wherever you set it.
- Boost 5 +8 dB
- Atten 5 -6.2 dB
- Both at 5 +6.2 dB / -2.7 dB
Every detail
captured
Boost and atten
Smooth and continuous, just like the original pots. Boost and atten work together across the whole spectrum: push and cut the same lows for a bigger bottom without the mud, or lift the highs while the atten smooths off the very top. Every pair interacts just like on the hardware.
The jewel
That red lamp glows with your input level, with the slow lag of a real filament, and goes dark when the EQ is out. A little piece of the original's soul.
In
One switch takes the EQ in or out, so you can compare instantly and hear exactly what that tube character adds.
Stepped where it counts
CPS, KCS and ATTEN SEL click into place like the rotary switches on the real unit, with the same 4, 7 and 3 steps as the hardware.
Every legend, every screw
A faithful 3D panel rendered under real light, so it looks and feels like the unit sitting in your rack.
EQP-1A
Most advanced version
of this classic EQ — Free
Free. No catch. Check out, get the key by email, use it on every machine you own.
Specifications
- Formats: VST3, AU and standalone app (64-bit)
- macOS 10.15 or later (universal: Intel and Apple Silicon) and Windows
- Stereo: the model runs on each channel, a perfectly matched pair
- Your presets are plain text files:
Documents/MTHRBORDon Windows,~/Library/Audio/Presets/MTHRBORDon macOS - Completely free to download and use forever
EQP-1A is a model of a vintage hardware design, made from our own measurements. It is not affiliated with or endorsed by the maker of the original. Pultec and EQP-1A are trademarks of their respective owners and are used only to identify the hardware we measured.
Long live the underground.