ALLNIC AUDIO D-5000 DHT, Owner'S Manual, Page: 4 / 21

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ALLNIC AUDIO AND THE PURE DIRECT HEATED TRIODE BREAKTHROUGH
In the early years of the last century, the directly heated triode (DHT) was invented independently,
and almost simultaneously, in the USA and Austria. This simple device, an anode, a cathode and a
grid in a vacuum contained in a glass bottle, transformed the world. Over one hundred years later,
the very first triode remains a favourite audio amplification device for devoted music lovers
worldwide.
Debate about the quality of the DHT’s sound reproduction potential continues even today. One of
the interesting aspects of these debates is the degree to which they ignore analysis of common,
fundamental assumptions about DHTs. Those assumptions are based on many decades of circuit
and mechanical experimentation and compromise. Indeed, because of the difficulty of using DHTs
for audio, many circuit design issues have evolved into assumptions about the audio characteristics
of DHTs themselves.
Allnic’s Mr. Kang Su Park has spent a lifetime studying and designing circuits and transformers for
use of DHTs in audio reproduction. Mr. Park has questioned basic assumptions about DHTs, re-
examined variations of DHT circuit designs, and researched and experimented rigorously. His work
has resulted in some remarkable audio power amplification devices. For example, Allnic’s 300B
amplifiers produce significantly more power than normally expected. They do this without
shortening tube life because the power increase is not achieved by increased bias. In conjunction
with an increase in power, Mr. Park’s 300B amplifiers also have exceptionally low distortion and
wide bandwidth.
Mr. Park successfully combined elements of what he learned and invented over decades to the
development and production of a pure, direct heated triode (DHT) based amplifier and preamplifier:
the A-5000 and L-5000, respectively. The main breakthrough was the design of a circuit, valve and
transformer combination with astounding measured results. The purity of its square wave
reproduction – as perfect as anything he had ever seen from a DHT valve amplification circuit – had
him questioning what he was seeing! Of course, he replicated these tests many times and recorded
them and their results before assuring himself that there was no mistake.
With such an unprecedented superior outcome for the circuit design, Mr. Park could not be satisfied
placing a DHT stage after one or two stages using indirectly heated triodes. That approach is used in
a number of commercially available preamplifiers using DHTs, but it is a compromise. It does not
result in PURE DHT amplification. It introduces the characteristics of indirectly heated triode sound
into the circuit. The output DHTs are only amplifying a signal already determined by the initial stage
indirectly heated triodes.
In contrast, Mr. Park has created devices that use DHTs at each amplification stage. In his design,
the output stage DHTs do not merely amplify the signal from indirectly heated triode stages. The A-
5000 DHT, L-5000 DHT, and H-5000 DHT amplifier, preamplifier and phono-preamplifier are pure
DHT, from signal input to output; and now, Allnic has produced the:
ALLNIC AUDIO D-5000 DHT DAC, WITH A PURE DHT ANALOG OUTPUT SIGNAL PATH.
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