The D5 uses one pair of large-diameter tubes, while the D5Pro uses three pairs to increase power output; otherwise, they are identical.
D5 Development Process
2015: The first-generation D5 pure power amplifier was released.
2017: The D5 integrated amplifier was launched.
2021: The D5PRO integrated amplifier was launched, increasing the number of power tubes from one pair per channel to three pairs in parallel.
Circuit Features
“Crescent Moon Scimitar” Dassault large-loop feedback-free amplifier circuitry
Warm, soft, comfortable, and pleasing to the ear—this is an amplifier suitable for sitting down and listening to music at a leisurely pace. The sound is remarkably expansive, open, and natural, without any harshness; it is truly pleasing to the ear. The bass response and extension are excellent.
High damping coefficient allows for precise control over any speaker. Because it is a large-loop feedback-free amplifier, its control is first-class and worth trying.
MBL preamplifier circuitry, powered by an independent parallel regulated power supply.
3-channel RCA signal input selection.
Materials Used
The D5PRO uses 6 pairs of tubes, 3 pairs per channel, with precise testing and pairing. MJL3281/1302 High Output Current Capability
All internal small signal and high current lines use Taiwan Teflon oxygen-free copper wire.
CMC pure copper RCA terminals.
Utilizes a 500W high-end Nippon Steel transformer.
12 10000uF audiophile-grade electrolytic capacitors. ELNA FOR AUDIO.
Power amplifier adopts a dual-to-mono design, with separate power supplies for the left and right channels, resulting in extremely high separation.
Features soft start and comprehensive speaker protection circuitry.
CNC machined all-aluminum high-precision chassis, 430*330*130mm.
Preamplifier uses a rear-mounted ALPS27 potentiometer.
Preamplifier uses a tube-based audiophile-grade single op-amp, OPA828.
AP Test Parameters: 800W load test data per channel (8 ohms)
Output RMS: 30.68Vrms
Channel Gain: 37.13dB 70.2 times
Signal-to-noise ratio: 108.5dB
Dynamic range: 108.5dB
THD distortion: 0.0033%
THD+N distortion: 0.010%
Frequency response bandwidth: ±0.046dB
Amplifier weight: 16kg, 17kg with packaging
Quadrant power consumption: D5 85W, D5PRO 90W
Output power: 120w*2/8 ohms; 240w*2/4 ohms Easily drives large speakers
Quality assurance and after-sales service
To ensure quality, every unit undergoes comprehensive AP testing to ensure it meets design specifications.
Tests include: bandwidth, noise (signal-to-noise ratio), dynamic range, distortion, intermodulation distortion, channel separation, amplification, etc.
72-hour stress test on the entire unit, 1-hour stress test at full 8-ohm amplifier load, and over 1 hour of listening practice.
The distortion of this machine at full power is as low as 0.003%
A pair of tube amplifier boards used by D5
The three-pair tube amplifier board used by D5Pro
The integrated amplifier features high-quality preamplifier circuitry:
The classic MBL6010 preamplifier core circuitry is used.
The OPA604AP op amp, which delivers tube-like sound, is used.
The ALPS27 potentiometer is placed post-amplifier to shorten the signal path and reduce noise.
The potentiometer extension rod connection shortens the signal transmission path and reduces interference.
The preamplifier is powered by a Class-A shunt-regulated power supply with excellent transient response and extremely low noise.
OMRON relay signal switching.
CMC high-quality RCA connectors.
Power amplifier circuitry: The main amplifier circuitry is derived from the renowned Swiss Dartzeel NHB-108, a legendary “crescent moon blade” worth 130,000 RMB. The main amplifier board is a 1:1 direct-engraved original, with identical component models and specifications, resulting in a sound identical to the original. The Dartzeel 108 amplifier utilizes a feedback-free circuitry, completely eliminating the influence of speaker back-electromotive force on the amplifier. The sound is natural, comfortable, and highly controlled. The acclaimed NHB-108’s patented minimalist broadband circuitry boasts a revolutionary design with powerful current output capabilities and incredibly beautiful sound quality. The output stage features a unique open-loop design with no global negative feedback, no negative feedback or compensation networks in the input or output stages, and only six transistors per polarity in the entire signal path.
D5PRO AP test with 8 ohm 800W load test
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