This is a unique equalizer – for several reasons. It has two times five fully parametric filter bands, each of which can be switched between constant Q and proportional Q! And there’s sheer unlimited headroom and a very special kind of EQ sound – thanks to 120V technology. Key Features: The PQ Mastering Equalizer is a fully parametric, dual-channel five-band equalizer. Both units are based on our 120V Rail Technology. The new PQ features the same high-quality characteristics as the previous model. Each channel can completely be activated or deactivated, thanks to Auto-Bypass, even automated in a freely selectable time frame. The PQ Mastering Equalizer – Model 1540/1544 is a new revised edition of the well-known SPL PQ Mastering Equalizer – Model 2050. All five bands can each be activated or deactivated and you got the possibility (for every single band) to separately switch between Constant Q and Proportional Q. This kind of circuit has not yet been achieved in any other equalizer. Thanks to the detented potentiometers, a precise recall is very easy to realize. You can also adjust parameters Gain, Frequency and Q in 41 steps with the detented potentiometers.