In 2012 Zapco introduced the new Z-Series of SQ amps. These amps were not conceived so much by our engineers, as by input from audiophiles and car sound fanatics around the world. We experimented with internal components and new circuits to see if we could take our amps to the next level of sound quality by investing in different internal components and circuit designs, and the resulting Z-Series amps were the results of this unique development method.  This year we stepped back and took a look at the amp that started it all. The Z-Series amplifier. We knew we could bring the price down, because over the last few years. This allowed us to build the Z-series AP and SP amps cost only a little more than the original Z-Series so the prices weren't that far apart. Now we have brought the Z-Series into the same plant as the newer models. That lowers the price, but what could we do the make it better? We saw that a lot of the non-critical parts from the AP and SP amps could used in the new Z-Series as well. Even with some of the SQ parts we save by buying more so we can use those in the Z-series also. Features and Functions  4-Channel, Class-AB Sound Quality Amplifier Stable into 4 ohms bridged or 2 ohms stereo load PWM MOSFET power supply High end Op-amps and Capacitors Variable FULL / LP / HP Electronic Crossover 0-12dB variable bass boost 4-way protection circuitry Wired remote control (optional) Panel mount RCA connectors  Specifications  Power @ 4Ω: 4 x 165 watts Power @ 2Ω: 4 x 275 watts Power @ 4Ω Bridged: 2 x 550 watts THD @ Rated Power  < 0.05% Signal to Noise Ratio > 100dB Frequency Response 10Hz to 30,000Hz ±1dB Input Sensitivity .5v to 8v Dimensions in mm: 190(W) x 62(H) x 444(L) Overall: 190(W) x 62(H) x 479(L)