The Mastering Version of the Massive Passive Stereo Tube EQ is a passive design that features mechanically detented knobs for the Gain and Bandwidth controls. These controls interact with each other and the maximum boost or cut is 11dB. At the widest bell, the maximum boost or cut is 6dB and the narrowest shelf maxes out at 12 dB. The Bandwidth step sizes are repeated in 16 steps. The Frequency select is already detented and is a Grayhill switch. It also interacts in shelf mode.

The Massive Passive is a parallel design that allows the bands to interact with each other. It was designed to allow much more EQ without sounding processed.

The Filters in the Mastering Version have been moved lower and higher than the normal version. Additionally, the Master Gain Trim controls in the Mastering Version are true 11 position 1/2 dB stepped Grayhill switches set up for a range between -2.5 to +2.5 dB of master gain trim.