DSP Amps
Subwoofer Box




4 x 150 W @ 2 ohm


D-class Fully Bridgeable

AF companion amplifiers are designed to add powerful amplifier channels to AF bit processor amplifiers. A plug-and-play signal input harness is included to make connection to AF bit amplifiers straightforward. AF companion amplifiers are also perfect for use with systems controlled and managed by a standalone bit processor, such as a bit One HD Virtuoso. AF companions have a “straight wire” architecture, without analog preamp functions such as crossover filtering, and are intended for use with external processors. AF M4D boasts four high-fidelity amplified channels 90W x 4 @4Ω*, 150W x 4 @2Ω* with the audiophile sound of the latest generation Audison D-Class technology. Higher switching frequencies, steeper filtering, and higher-tolerance components deliver sound above and beyond the expectation of Class D – in an amazingly compact package! The audio band is extended up to 40 kHz earning the coveted High-Resolution certification. Bridging channel pairs results in 300W x 2 @4Ω*, guaranteeing flexible and powerful performance.

*Output Continuous Power (RMS) @14.4 VDC, 1% THD, all channels driven.

Amplifier Tech Data

Channels 4
Class D-Class
Efficiency 81%
Hi Level Input Yes
Low Level Input Yes
Digital Input No
Power supply voltage / fuse 11 ÷ 15 VDC
Operating power supply voltage 6.5 ÷ 17.5 VDC
Idling current 1.04 A
Idling current when off 0.007 mA
Consumption @ 14.4 VDC, 2Ω, Max Musical Power 29 A
Remote OUT 6.5 ÷15 VDC (150 mA)
Remote IN 4 ÷15 VDC (1 mA)
ART - Automatic Remote Turn on/off from OUTPUT BTL speakers (Selectable) 1.5 VDC

Amplifier Stage

Distortion - THD @ 100 Hz, 4Ω, 70% Rated Power 0,03%
Bandwidth A (-3 dB, 2 VRMS, 4 Ω): 10Hz ÷ 42kHz
S/N ratio A (A weighted @ 1 V): 103 dBA
Damping factor A (100 Hz, 4Ω, 2 VRMS): 95
Input sensitivity Pre-In 0.6 ÷ 6 VRMS
Input sensitivity Speaker-In 2.2 ÷ 22 VRMS
Total Power RMS 600 W
Minimum load impedance 2Ω:
Output Power (RMS) @12.0 ÷ 14.4 VDC, 1% THD 4Ch @ 4Ω: 90 W x 4

4Ch @ 2Ω: 150 W x 4

2Ch (bridge) @ 4Ω: 300 W x 2
Adjustable Crossover No

CEA Specifications

Output power @ 4Ω, 1% THD+N, 14.4 V 90 W x 4
SN ratio (ref. 1W output) 82 dB


Remote Sub Volume ±12 dB


Fuse 1 x 30 A
Weight 1.49 kg


Dimension A 200 mm
Dimension B 47 mm
Dimension C 134 mm


The optional VCR-S2 subwoofer volume control provides the ability to adapt the subwoofer level to any personal preference and favorite music genre. VCR S2 features a bulletproof Molex connector.
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AF LINK accessory cable can be connected to have 6 additional channels configurable on the bit Drive software.

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  • Improved audio performance and power thanks to the latest generation of ADT (Audison D-Class) technology
  • Unbeatable power/volume ratio up to 0.47 W RMS/cm³ reaching 81% of efficiency
  • Hi-Res compatibility performance, with an extended audio band up to 40 kHz
  • Maximum versatility thanks to the possibility of using the bridging option for each pair of power outputs

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