SR 4.500
Amplifier
|
4 Ch
|
4×125 W
|
D-class
As far as the electronic design is concerned, every aesthetic and functional detail of the Audison SR 4.500 has been taken care of, resulting in a compact amplifier made of extruded aluminum with rounded corners, which facilitates the installation of the product in narrow spaces. Thanks to the generous heat sinks on the two short sides of the amplifiers, there is no need for internal cooling fans, which often cause noise and dust accumulation. In keeping with tradition, the SR amplifiers confirm their vocation for versatility by including on all models a complete filter section, suitable for any kind of audio system configuration. The controls, protected by a satin-finished aluminium panel, are located on the top panel of the amplifier, so that they can 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.
Amplifier Tech Data
| Channels | 4 |
| Class | D-Class |
| Hi Level Input | Yes |
| Low Level Input | Yes |
| Digital Input | No |
| Power supply voltage / fuse | 11 ÷ 15 VDC / 2 x 25A |
| Operating power supply voltage | 6.5 ÷17 VDC |
| Idling current | 1.7 A |
| Idling current when off | 0.09 mA |
| Consumption @ 14.4 VDC, 2Ω, Max Musical Power | 40 A |
| Remote OUT | 6.5 ÷ 15 VDC (150 mA) |
| Remote IN | 6.5 ÷ 15 VDC (1 mA) |
| ART - Automatic Remote Turn on/off from OUTPUT BTL speakers (Selectable) | 1.5 ÷ 7 VDC |
Amplifier Stage
| Distortion - THD @ 100 Hz, 4Ω, 70% Rated Power | 0.08 % |
| Bandwidth A | 10 Hz ÷ 35 kHz |
| S/N ratio A | 105 dBA |
| Damping factor A | 200 |
| Input sensitivity Pre-In | 0.2 ÷ 5 VRMS |
| Input sensitivity Speaker-In | 0.8 ÷ 20 VRMS |
| Total Power RMS | 880 W |
| Minimum load impedance |
@4Ch: 2Ω @ 3Ch: 2Ω + 2Ω + 4Ω @ 2Ch: 4Ω |
| Output Power (RMS) @12.0 ÷ 14.4 VDC, 1% THD |
4Ch 130 W x 4 (4Ω) 4Ch 220 W x 4 (2Ω) 3Ch 120 W x 2 (4Ω) + 480 W x 1 (4Ω) 3Ch 220 W x 2 (2Ω) + 440 W x 1 (4Ω) 2Ch 450 W x 2 (4Ω) |
| Adjustable Crossover | Yes |
CEA Specifications
| Output power @ 4Ω, 1% THD+N, 14.4 V | Output power @ 4Ω, 1% THD+N, 14.4 V: 125 W x 4 Ch |
| SN ratio (ref. 1W output) | SN ratio (ref. 1W output): 83 dBA |
Inputs
| Input Type | Pre-In / Speaker-In |
| Filters Outputs | PRE OUT full range (Input A) |
| Filter Pass A | Front Ch Filters - Full Hi-pass: 50 ÷ 3.2k Hz @ 12 dB/Oct. |
| Filter Pass B | Front Ch Filters - Full Lo-pass: 50 ÷ 3.2k Hz @ 12 dB/Oct. |
| Filter Pass C | Rear Ch Filters - Full Hi-pass: 50 ÷ 3.2k Hz @ 12 dB/Oct. |
| Filter Pass D | Rear Ch Filters - Lo-pass: 50 ÷ 3.2k Hz @ 12 dB/Oct |
| Channel Mono | A/B Ch MONO IN (on/off) Yes |
| Inputs/Outputs Sub CH | (-20 ÷ 6) dB |
| Inputs/Outputs Bass Boost | B Ch (0 ÷12) dB |
Other
| Weight | 2.12 kg |
Dimensions
| Dimension A | 264 mm |
| Dimension B | 234 mm |
| Dimension C | 155 mm |
| Dimension D | 135 mm |
| Dimension E | 47.5 mm |
Features
- Elegant and functional design with rounded corners to minimize space, facilitating installation.
- Built-in USS (Universal Speakers Simulator).
- Full built-in crossover section.
- Optional VCR-S1 remote control offers the possibility to adjust the subwoofer level (-20 / + 6 dB) to your musical preference.
- Balanced high-level inputs for connecting to the OEM head unit speaker output
- Low-level RCA for after-market speakers.
- ART (Automatic Remote On/Off) function.
- Remote IN / OUT socket to allow control of multiple amplifiers.
- PRE-OUT allows for system expansion.
Technologies
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.
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.
