Thursday, September 15, 2011

Nova NIA2 integrated amplifier
























































The integrated amplifier NIA2 was developed around an innovative circuitry used, exclusively, by Nova on their products. The peculiarity of this circuit is the total absence of any form of negative feedback. It 'was in fact used a particular solution that allows you to compensate for nonlinearity, intrinsic active devices, rather than correct them with feedback. The negative feedback or negative feedback, used in almost all the achievements in trade, often leads to a characterization of the sound, which is referred to as unnatural or "transistor", as well as to determine, often, a compression and a depletion in the harmonious music played.

In order to minimize manipulation of the musical signal using the circuit comprises only three stages of amplification, the first, without feedback, with the function to amplify the voltage and the second, consisting of a pair of MOSFETs, polarized Class A for the control of the power devices. The final buffer consisting of ten MOSFET, provides the current amplification.

The amplifier consists of two independent mono units, housed within the same container. Were in fact separate the different components of each channel, from the two 500VA toroidal transformers, placed inside a shielded metal and resin.

For the volume control was used a digital potentiometer, Analog Devices - 1000 steps, which have been "compressed" into 100 levels (0-99), in order to obtain a pseudo-logarithmic adjustment. This component consists of a network of precision resistors switched by MOSFETs. There are not so, as in other similar achievements, active devices (op amps) that could cause a degradation in performance music.

Due to the absence of feedback the individual active devices are selected individually.

The passive components, used, includes elements of high quality electrolytic capacitors with very low internal impedance, to those of polypropylene, metal film resistors with low noise. Every single component has been chosen, after many listening tests, in relation to the real sound quality.


Specifications

Output power (RMS): 170W 8Ohm
Maximum output current: 25A continuous, 120A peak                          
Output impedance: <0.3 Ohm
Input impedance: 20 kOhm
Frequency response :5Hz to 500kHz (-3dB)          
Distortion (THD): <0.1%                    
Maximum input voltage: ± 5 V peak
The impedance headphone jack output: 50 Ohm

Voltage:230V (200V ÷ 265V)
Power consumption at idle:     <80W                          
Maximum power consumption:   <500 W
Inputs:5 line (1-balanced) + 1 optional phono
Dimensions: 440 x 420 x 170 mm (WxDxH)          
Weight: 30 kg                    
Chassis Material: Aluminum

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