Integrated Amplifier

The Integrated Amplifier
Twice as tall, higher output power and even more connection facilities – the PA 2500 R exceeds the specification of the PA 2000 R in many areas, but its character in terms of sound quality is in no way inferior to its smaller sibling. This by no means goes without saying, because very powerful amplifiers often forfeit the finer points of dynamics and detail tracery. Our PA 2500 R integrated amplifier circumvents this danger: its basic circuit is the same as that of the PA 2000 R, and even the circuit board layouts are identical. However, its heat-sinks are twice the size, and the case accommodates two of our new high-performance mains power supply units, with the result that it can deliver more than 280 Watts of continuous power per channel into 4 Ohms loudspeakers. The amplifier is therefore effortlessly capable of controlling speakers which are extremely critical in terms of phase and impedance. The PA 2500 is even more powerful than the smaller machine but retains the same dynamism and cultured sound.

Technology.
The quality of any output stage is deter­mined to a very great extent by the mains power supply as well as the circuit topology. Mains power supply units must be as stable and resilient as possible, to ensure that the voltage they generate does not collapse even when very high peaks are encountered. In conventional equipment this requires very large transformers, but the limited space available in the low-profile R-series machines spurred on our en­gineers to develop an ingenious alternative solution: a regulated high-frequency sine-wave mains power supply with generous reservoir capacity, capable of delivering up to 1200 Watts without problem. The mains power supply can deliver very large quantities of current extremely quickly, even when the gradient of the peak signals is steep. Our experience in building amplifiers over a period of thirty years has taught us the importance of the quality of audiophile modules for the outcome in terms of sound quality, and that is why we choose our components with great care and then select them according to strict criteria, to ensure optimum characteristics for each specific application.

Specifications:
Pre-amplifier stage
Frequency response + 0 / − 3 dB 0,5 Hz – 300 kHz
Signal / noise ratio, unweighted / A-weighted     105 / 109 dB
Total harmonic distortion/Intermodulation< 0,001 % / < 0,001 %
Channel separation> 90 dB
Loudness-Switchable, variable to suit loudspeaker efficiency
Nominal input sensitivity             
High level (RCA) 4 × 250 mV … 4 Veff/20 kOhms
Balanced (XLR)  3 × 500 mV … 8 Veff/5 kOhms
Phono-MM (optional*)
Phono module replaces one high-level input        1 – 5 mV,
16 Capacitances
Phono-MC (optional*)
Phono module replaces one high-level input
60 – 1000 µV,
16 Impedances gs