The Redline collection is DD Audio's “prices from” collection. Nevertheless, the products are quite usable stuff. Launched in 2022, Redline amplifiers are very simple devices that deliver the power they promise and a little more. The collection is also well stripped, with a mono amplifier for playing the subwoofer and a 4-channel amplifier for playing the main speakers.

The physical size of these amplifiers is very small so installation is painless even in a tighter car. The amplifiers also have speaker-level inputs, so you can connect to the car's original player. 

DD Audio SA300.4 is mini chassis amp designed to make space constrained installations a breeze. Don’t be fooled by its small stature in 4 ohm bridged mode this little powerhouse can produce over 2 x 120Watts- Great sound quality- Mosfet power supply amplifier- 4 gauge set screw power terminals- 12 gauge set screw speaker terminals- Variable 12dB/oct crossovers- Remote subwoofer control (SA500.1)- 5-way protection: Speaker short, thermal, overload, HI/LOW voltage, DC offset.

Features:

• Class D 4-channel amplifier
• power stereo: 4 × 65 W @ 4 ohm, 4 × 75 W @ 2 ohm, RMS
• power when connected to a bridge: 2 × 120 W @ 4 ohm when bridged
• stable 2 ohm stereo, 4 ohm mono
• input sensitivity: 0.2 - 6.0 V (RCA connection)
• input sensitivity: 1.1 - 20 V (speaker level)
• power and ground terminals can accommodate 25 mm² cables
• the speaker terminal can accommodate 4 mm² cables
• playback range 30 to 30,000 Hz
• low pass filter: 35-250 Hz
• high pass filter: 35-250 Hz
• dimensions WxDxH: 180 x 43 x 96 mm