The Massive Passive is a passive design and not a "true parametric". A true parametric implies non-interacting controls. In the Massive Passive, the "GAIN" and "BANDWIDTH" controls DO interact (on purpose). We cannot create a "GAIN" switch that is set up for "consistent" 1/2 dB steps. When you change the "BANDWIDTH" the step size must and will change. On the regular version, you get a full 20dB boost or cut only when: the bandwidth is fully clockwise (narrow) in bell mode or fully counter-clockwise in shelf mode. Here on the Mastering Version, this maximum boost or cut is 11dB. Conversely at the widest bell, the maximum boost or cut is 6dB and the narrowest shelf maxes out at 12 dB. A similar situation is also true for the bandwidth detents. So in this new Mastering Version, do not expect a certain dB change per step as it will vary according to where the bandwidth is set. But whatever the step sizes are, they will be repeatably 16 steps. The FREQUENCY select is already detented as it is and always has been a Grayhill switch. It also interacts in shelf mode.
 
MASTERING VERSION FEATURES
All-Passive tone sculpting circuitry
Unique Shelf curves use the "bandwidth" control
Overlapping and Interleaved Frequency choices
Every band switchable to shelf or bell
Vacuum tube make-up gain and line drivers
Parallel symmetrical topology
Premium components throughout
HP and LP Filters
STEPPED GAIN trims -2.5 to +2.5dB in 11 steps of 1/2dB each
Metal Manley mechanically detented GAIN and BANDWIDTH control knobs
 
MASTERING VERSION SPECIFICATIONS
Inputs: Balanced XLR & 1/4” (accepts unbalanced)
Outputs: Balanced XLR (accepts unbalanced) & Unbalanced 1/4” 
Level +4 dBu nominal
Bypass Switch bypasses EQ & tube circuits (not hardwire)
44 Frequencies (roughly 1/4 octave spacing)
Frequency Range: 22 Hz to 27 kHz
EQ Boost/Cut Range : Maximum 11dB boost or cut
Nominal Q range: 1.5 to 3 (uniquely active in shelf modes)
Frequency Response: +/- 2 dB: 8 Hz to 60 kHz
Maximum Output @ 1.5% THD +37 dBv; +26dBv @ 20 Hz
THD & Noise (1kHz @ +4 dBu): 0.06%
Noise Floor (referred to +4dBu): -85 dB (A Weight)
Dynamic Range: 120 dB
Tube Complement: 2 x 12AU7, 4 x 6414
Auto-mute warmup delay = 20 seconds
Power Consumption (120/240VAC): 44 watts
Mains Voltage & Frequency (VAC/Hz): Internal Universal Power Supply 90-254 VAC / 50-60Hz
Mains Voltage Frequency: 50~ 60Hz
Size (3U): L 19” x W 10” x H 5.25”
Unit Weight: 15.5 Lbs.
Shipping Box: L 23” x W 15” x H 10”
Shipping Weight: 26 Lbs.