Denon PMA-2500NE Reference Amplifier – Audible Fidelity Ltd
The pinnacle of Denon know-how over the past 100 years, the PMA-2500NE is a tour-de-force in 2 channel amplification and challenges amplifiers costing twice the price.
A ‘must hear’ product recommended by Audible Fidelity.
Thanks to the rear USB-B input and embedded high quality D/A converter, the PMA plays high resolution files up to 384kHz/32bit and DSD up to 11.2MHz from a computer in impeccable sonic quality. For the best performance from analogue inputs, the PMA features an Analog Mode which allows it to switch off all un-utilized sections like the digital input circuitry or the low noise display for an unaltered audio reproduction.
High Gain Amp Construction
The amplifier circuitry has been changed from the conventional two-stage configuration to a high-gain power amp in a single-stage configuration for a more direct signal path.
A highly pure sound has been made possible by reducing the number of devices through which audio signals pass and shortening signal paths to an absolute minimum. The protection circuitry for the power amp output stage has also been considerably improved.
The current limiter has been eliminated in favor of a system that monitors power transistor temperature changes in real time, and the current capacity of driver stage transistors has been boosted to 2.0A from 1.5A.
As a result, the instantaneous current supply capability of the amp has been more than doubled (110A) compared to conventional designs and speaker drivability has been dramatically improved (damping factor: greater than 700, 20 Hz – 20 kHz).
To achieve impeccable balance between delicate details and vigor in sound, the PMA-2500NE employs Ultra High Current MOS (UHC-MOS) FETs, capable of producing ample current in a single push-pull configuration which deliver superior linearity in the output stage throughout the sonic range from musical details to robust current.
The PMA-2500NE is endowed with high-voltage, large-capacity UHC-MOS FETs (peak current of 210A). In addition, the Dual FET + cascade bootstrap connection maintains a constant voltage for the UHC-MOS while improving temperature stability, to reliably bring out the superior acoustic characteristics of UHC-MOS.
The PMA-2500NE provides “EXT.PRE” input terminals – fixed gain inputs – that can be used for connecting an external pre-amp and using the PMA-2500NE as a power amp. This is convenient when connecting an A/V amp via its pre-outs so that the listening space with the same front speakers can be used as a home theater.
To accurately synchronize digital circuits, the PMA-2500NE’s DAC Master Clock Design treats the DAC as the master when clock signals are supplied. Positioning the master clock immediately adjacent to the D/A converter (DAC) suppresses jitter and ensures optimum precision in D/A conversion.
In addition, the quality of the clock, which becomes the reference for semiconductor operation, is extremely important for ensuring that the digital audio circuitry performs at its maximum potential. The PMA-2500NE thus employs a clock oscillator to dramatically reduce phase noise that is the displacement of frequencies. The PMA-2500NE is further equipped with two clock oscillators, one for each sampling frequency (44.1 kHz and 48 kHz), that can be switched between the frequencies to thoroughly suppress jitter.
For digital input, the PMA-2500NE employs Advanced AL32 Processing Plus, the latest version of Denon’s analogue waveform reproduction technology which utilizes unique data interpolation algorithms and also supports high-resolution 384-kHz/32-bit PCM signal input.
These algorithms interpolate points that should exist before and after the points in large quantities of data to achieve a smooth waveform that is close to that of the original signal. By carefully restoring data that was lost during digital recording, the resulting playback sound is highly detailed, free of interference, accurately localized, richly expressive in the lower range, and beautifully faithful to the original sound.