SR 4.300

HIGH POWER IN A COMPACT SIZE

Class D amplifiers are also called “switching amplifiers”, since their efficiencies are arrived at by rapid on and off switching of the output transistors. Audison Class D uses a much higher switching frequency than most other amplifiers. You might think the switching frequency for all Class D amps are the same, but Class D chipsets allow significant latitude in many design aspects, such as switching frequency and timing. Most companies use as low a switching frequency as possible – this makes the timing easier to manage, and allows the use of lower-precision components which cost less. ACD uses a switching frequency twice as fast as many other modern Class D amplifiers. Higher switching frequencies require incredibly precise timing, which require higher-tolerance components to be used in order to keep the timing pulses from overlapping (that causes catastrophic failure of the output transistor). Audison uses very high-tolerance component parts to keep the timing correct even during temperature extremes (temperature changes shift the values of analog components). To Audison, this is worth the cost, since the higher switching frequency of Audison Class D moves noise much farther away from the audible band.

Audison Class D also uses a steeper 4th-order analog lowpass filter, rather than the simpler 2nd-order lowpass filters usually used in competing designs. The steeper filter will keep noise much lower in amplitude – which is good for controlling EMI and for preventing infrasonic noise getting to the tweeters. It also keeps phase shift outside the audible range. The cost is higher – twice as many components are needed for a 4th order filter compared to the usual 2nd-order filter, and each output channel needs its own filter – but Audison determined through exhaustive listening testing that this design was the best-sounding approach.

EDGELESS DESIGN

As for the electronics design, the Audison style center has taken care of every aesthetic and functional detail, obtaining a compact amplifier made of extruded aluminium with rounded corners that ease the installation of the product in narrow spaces. Thanks to the generous heat sinks on the two short sides of the amplifiers, internal cooling fans are not necessary, which are often cause of noise and dust accumulation.

COMPLETE CONTROLS ON UPPER PANEL

As per tradition, the SR amplifiers confirm their vocation for versatility by including on all models a complete filter section, suitable for any type of audio system configuration. The controls, protected by a satin-finish aluminium panel, are located on the amplifier upper panel, to be easily reached from above even after the product has been installed. When the system includes an Audison bit processor, the filter section can be totally excluded.

Thanks to the integration of Audison USS technology (Universal Speakers Simulator) in the high-level inputs, the SR amplifiers can also be appropriately connected to OEM sources featuring the “speaker load detection” function that monitor the presence of a low-impedance load to enable audio outputs.

LIMITLESS CONNECTIVITY

All models are equipped with high-level balanced inputs for connection to the OEM Head Unit speakers output and low RCA level for the after-market ones. When the high level input is used, the ART function (Automatic Remote Turn-On / Off) can be enabled to control the switching on of the amplifiers with the head unit switch-on button.

In addition, there is a remote IN / OUT socket to allow the control of multiple cascaded amplifiers switch on when required.

The SR 1.500, SR 4.300 and 4.500 models recreate the PRE-OUT signal by using the Speaker-IN input to interface it with OEM sources only equipped with amplified outputs, allowing the system expansion.

Attachments:

Audison SR 4.500 Tech Sheet

Audison SR 4.500 Manual