GOLY PG Porter Grinder Mastering EQ (Rev 2023)

Product Description

The GOLY PG Porter Grinder Mastering EQ is based on the highly regarded “NetEQ”, by the late Barry Porter. After many years of listening tinkering with the design, building, and listening, and adjusting, and listening, and doing custom units with various solutions -- and listening -- the only thing that remains unchanged is the parallel filter section. The in and output sections, the high and low pass filters, the layout of the circuit, the Q circuit, and the whole implementation of it has been redesigned, and when the listening tests were done, GOLY took a really deep dive into the details and precision of all the controls. The result is still a Porter at its core, but also, very much a Grinder.

2023 REVISION

The sound and the circuit remains exactly the same as the original. Gain is ±6 dB on a custom 41-step pot, with center tap, in order to obtain a perfect, zero gain reference. Frequency is set up on a custom 41-step pot, which means, you have an almost continuous flow while dialing in your frequency. The torque is adjusted to give you a stepped feel while doing more careful tuning. Design of the interface and control scales reflects these changes, and it's possible to make perfect recalls, even at this resolution.

The Q was changed from RMS to peak gain behavior. RMS behavior keeps the energy constant, while the peak behavior keeps the peak level constant. Think of a balloon, if you squeeze it to make it narrower, it gets longer (higher peak, same amount of energy), but if you let a little air out, it will stay the same height as before (static peak, less energy). What is preferable comes down to temperament, but aside from the practical aspects, the redesigns gave a less ringy and more intuitive behavior, especially at more narrow settings.

In the original design, the high and low pass filters were added in series with the core circuit, and they were done with a simple RC filter on an opamp. They always seemed be a bit “out of place” with the bands standing out relative to the rest of the EQ, so the 2023 Revision nixes Porter’s HP/LP add-on, and with the help of a few relays, they are tapped directly into the core of the parallel circuits. Their resonance peaks don’t look very good on paper, but they sound amazing, and they are fully sympathetic to the other bands, when they are engaged.

The center section features a Bypass which allows you to bypass the filter section. It also includes MS which wraps the MS encoder and decoder around the whole filter circuit. The MS circuit is built on modern, precise, integrated circuits.