Parasound A 23+: Impressive power amplifier

The Parasound A 23+ power amplifier is a more powerful version of the previous A 23 model. The new product also received a new 1.1 kVA transformer and a set of 54,400 μF capacitors. Now the maximum power of the amplifier in bridged mode reaches 500 watts. Like the older model, the A23+ is equipped with symmetrical and asymmetrical input terminals with sensitivity control for better matching with the preamplifier. The Parasound Halo A23+ weighs exactly 12.2 kilograms. The Parasound A 23+ amplifier is built according to the proprietary concept laid down by the developers back in the eighties, called Direct Coupled.

The idea is quite simple: the signal path must be extremely short and contain no feedthrough capacitors or inductors. In traditional circuit design, the audio signal is passed through capacitors and inductors in order to filter out potentially dangerous components and stabilize the amplifier. In the case of Parasound, this function is performed by special circuits that monitor the state of the input signal without direct intervention. If necessary, the operating mode is automatically adjusted or the amplifier is turned off in the event of an emergency.

The input stage of the amplifier is assembled on JFET transistors, and the driver stage is assembled on MOSFET transistors matched in pairs. Both types of transistors are field-effect, due to which they have high speed and reduced noise level. At the output, there are sixteen pieces of traditional bipolar transistors with a maximum operating frequency of 60 MHz and a maximum current of 15 A. Such characteristics provide a solid reserve both in power and in bandwidth, which allows to obtain a low level of distortion in the operating range of loads and frequencies. That is why the manufacturer calmly shifted the upper limit to 100 kHz. The Parasound A 23+ amplifier uses a transformer with a capacity of 1100 VA. Bipolar transistors are installed at the output, and the field-effect transistor in the intermediate stage is designed to provide sound close to a tube.

Given the symmetrical design of the Parasound preamplifiers and the Parasound A 23+ power amplifier, the best results (detail, stage, dynamics) were achieved by connecting the components to each other and to the source with balanced cables. But even with a normal connection, the Parasound duo demonstrates a warm and heartfelt sound that is ideal for the sensual manner of performance. Piercing piano etudes become simpler and more understandable. After long listening, you begin to understand that the unusually natural sound style of Parasound captivates the listener with its precision in conveying emotions and the warm, comfortable sound of tube amplifiers. The Parasound A 23+ stereo amplifier will make your acoustic systems sound amazingly new.

Parasound A 23+ Specifications

Power per channel at 4 ohms 240 watts
Power per channel at 8 ohms 160 watts
Output power bridged into 4 ohms or 8 ohms 500 watts
Intermodulation distortion <0.03%
Peak-to-peak output current 45 amps
Slew rate 130 volts/ms
Crosstalk (at 1 kHz) 80 dB
Crosstalk (at 20 kHz) 60 dB
Transient intermodulation distortion Below measurable limits
Damping factor >800 at 20 Hz
Total harmonic distortion <0.03% (full power), <0.01% (typical)
Input sensitivity 1000 for 28.28 volts; THX level; 1100 mW at full power
Input impedance 33 kOhm
Frequency response 5 – 100,000 Hz, +0/-3 dB at 1 W
Signal-to-noise ratio 116 dB
Power consumption 500 W
Inputs/Outputs
Linear balanced (XLR) input Yes
Linear outputs 1 stereo RCA
Linear inputs 1 stereo RCA, 1 stereo XLR
Power supply 220 V
Dimensions (WxHxD) 438 x 105 (92 excluding feet) x 337 mm
Weight 12.2 kg