Per's Audi S4 Website

 

I chose the DC Reference series from Zapco for a couple of reasons:

1. First - they're great amps with a long, accomplished history of top notch performance
2. Zapco amps utilize balanced inputs (Symbilink), which basically eliminates any interference that may crop up in the car. I was especially sensitive to this given driving the system with a PC.
3. This series has USB control of its built-in digital processor, which allows me to configure them via the integrated PC.

From the website:

ZAPCO introduces the DCS series of Reference amplifiers. This series shares the same platform as the analog Reference amps and the same power mix. This means lots of power and clean sound in both lines. The differences between the amps lie primarily in two areas. First, as the initials imply, the new series is digitally controlled. We know Zapco's not the first to do digital control…just the first to do it right. Each ZAPCO DCS amp features a USB input. This allows a PC to be hooked directly to the amp to set all functions. All functions can be set as stereo pairs or as individual channels. These DSP functions include:

1 - Output and input Gain
2 - Input mode: Rt, Lft, or Sum Mono
3 - Crossover mode: High Pass, Low pass, Band Pass
4 - Crossover Slope from 6 - 24dB
5 - Q-Bass Equalization
6 - Network Node Position
7 - Time Delay by both time and distance
8 - 10 bands of Parametric Equalization per Channel

• Zapco DC Reference 350.2 - drives front Dynaudio component speakers
  

Stereo, 4 ohms: Stereo, 2 ohms: Bridged, 4 ohms: T.H.D. + Noise: S/N Ratio: Slew Rate: Damping Factor: Dimensions:

2 x 100 Watts 2 x 170 Watts 1 x 330 Watts <0.025% @ 4 ohms >96dB >29V/uS >200 @ 4 ohms 16.38"L x7.12"W x 2.35"H

• Zapco DC Reference 500.1 - drives DLS subwoofer
  

 

Mono, 4 ohms: Mono, 2 ohms: T.H.D. + Noise: S/N Ratio: Slew Rate: Damping Factor: Dimensions:

1 x 350 Watts 1 x 500 Watts <0.04% @ 4 ohms >80dB >25V/uS >250 @ 4 ohms 14.01"L x7.12"W x 2.35"H