Advanced Ultra-High Current (UHC)-MOS Single Push-Pull Circuit for balancing Power and Details
To achieve an impeccable balance between delicate details and vigour 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 delivers superior linearity in the output stage throughout the sonic range from musical details to robust current. The technique of driving multiple amplifier devices in parallel to secure robust current has solved the problem of muddiness in sound caused by uneven performance among the devices. And to achieve musical expression filled with the delicate nuances of sound, Denon has continued to focus on amplification performed by one pair of devices. The PMA-2500NE is endowed with high-voltage, large-capacity UHC-MOS FETs (peak current of 210A). In addition, the Dual FET + cascode 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.
Direct Mechanical Ground Construction to minimise unwanted vibration
The power section, mounted on a sub-chassis solidly constructed with three layers of 1.6mm thick steel plates, has been positioned in the centre of the PMA-2500NE. With heat sinks on both sides, this construction of well-balanced mass is in an ideal location to prevent unwanted vibration from affecting sound quality. In addition, the feet supporting the heavyweight of the power transformer, heat sinks, and chassis are made of highly rigid, solid Bulk Molding Compound (BMC), and high-density felt pads attached to the bottom of the feet further absorb vibration.
Advanced AL32 Processing Plus supporting 384-kHz/32-bit PCM input
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. With the PMA-2500NE’s digital input, high-quality analogue signals that pass through Advanced AL32 Processing Plus are sent to the amp block at the stage that follows.
6-block chassis configuration
The PMA-2500NE’s chassis is configured of six independent blocks that house the phono equalizer and input circuitry, volume control circuitry, USB-DAC circuitry, amplification circuitry, power section, and the control section. The chassis constructed with 1.6mm thick steel plates protects the signal circuits from external vibration and eliminates the adverse effects of mutual interference among the circuits.
USB-DAC supporting up to 11.2-MHz DSD and 384-kHz/32-bit PCM
The PMA-2500NE provides USB-DAC functions that support high-resolution 11.2-MHz DSD and 384-kHz/32-bit PCM input signals. DSD transmission methods support ASIO native playback and DSD Audio over PCM Frames (DoP) with Wasapi or Kernelstreaming. Since asynchronous transfer is controlled by the PMA-2500NE’s master clock rather than the clock of a computer the transfer is free of jitter. The D/A converter used in the PMA-2500NE is the same 384-kHz/32-bit DAC PCM1795 used in the DCD-2500NE to deliver a clean, high-grade sound.
Robust power supply circuitry
The PMA-2500NE is equipped with two transformers that have been mounted facing opposite directions in a leakage cancelling (LC) mount system to cancel mutual influences of magnetic flux, a source of noise, leaking from the transformers. Denon’s custom-designed, large-capacity electrolytic capacitors have been used for rectification, and low-loss, low-noise, high-speed Schottky barrier diodes have been used in the rectifier circuitry. This ensures a sufficient supply of clean current. To achieve a “simple & straight” circuit configuration, the connection unit between the diode unit and the block capacitor has been removed to drastically shorten the current supply line to the power amp. Extremely thick OFC wiring material has been used for the power line to reduce impedance.