ALLNIC AUDIO L-5000 DHT 소유자 매뉴얼 - 페이지 4

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INTRODUCING THE L-5000 DHT PREAMPLIFIER

Allnic Audio and the Direct Heated Triode Breakthrough

In the early years of the last century, the directly heated

triode was invented independently, and almost

simultaneously, in the USA and Austria. This simple device,

an anode, cathode and a grid in a vacuum contained in a

glass bottle, transformed the world. With all the

applications in which it has been employed, and with all the

changes in electronic design for audio reproduction that

have occurred since its invention, it is remarkable that over

one hundred years later, the very first triode, the simplest

vacuum tube audio signal amplifier, despite the

imperfections ascribed to it, remains a favourite audio

amplification device of many devoted music lovers

worldwide.

Debate, on both subjective and empirical bases, about the

quality of the directly heated triode'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 based on

decades of circuit and mechanical design experimentation

and compromise, about the use of these devices. Indeed,

because of the difficulties in application of directly heated

triodes in audio circuits, many issues arising out of circuit

design problems related to them have evolved into

assumptions about the audio characteristics of the valves

themselves.

Allnic's Mr. Kang Su Park has spent a lifetime studying and

designing circuits and transformers for application of direct

heated triodes for audio reproduction. By questioning basic

assumptions about the valves and re-examining the original

and many historical variations of circuit designs for them,

and experimenting constantly in a framework of rigorous

application of theory, Mr. Park's work has resulted in some

remarkable audio power amplification devices. With the

300B, for example, his creations produce significantly more

power than is expected (without shortening valve life

because the power increase is not achieved by increased

bias), in conjunction with exceptionally low distortion and

wide bandwidth.

Now, Mr. Park has successfully combined elements of what

he has learned and invented over decades to the

development and production of a pure, direct heated

triode (DHT) based preamplifier. The main breakthrough,

which came after several years of work applying all he

knows, was the design of a circuit, valve and transformer

combination the measured results of which astounded

him. 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 tested and re-tested, replicated and

recorded these results many times before assuring

himself that there was no mistake.

With such an unprecedented outcome for the circuit

design, Mr. Park could not be satisfied merely with

placing a DHT stage after one or two prior stages of

amplification using indirectly heated triodes. This

approach is used in a number of commercially available

preamplifiers using DHT's, but it is a compromise. It does

not result in PURE DHT amplification; it necessarily

introduces the characteristics of indirectly heated triode

sound into the circuit, so the output DHT's are only

amplifying a signal already affected by the indirectly

heated triodes in the prior stage or stages.

Mr. Park, though, has created a preamplifier that uses

DHT's at each amplification stage. In his design, the

output stage DHT's are not merely amplifying the signal

from previous, indirectly heated triode stages. The L-5000

DHT preamplifier is pure DHT - from input to output.

Of course, Mr. Park is not the only builder who has

accomplished this, but to our knowledge no other pure

DHT preamplifiers have been commercially available.

There are serious and significant reasons why such

preamplifiers could not be acceptable in the marketplace.

First among them has been the enormous problem of

microphonics. One of the many special elements of Mr.

Park's design is

reduction of microphonic influence on the

DHT's

Where others have sometimes accepted the effects of

this problem because even with it they prefer the incredible

realism of the pure DHT approach,

creating a circuit and mechanical design that

DHTs' susceptibility to microphonic influence to insignificance

Like the Allnic L-3000, which is an indirectly heated triode

preamplifier, the L-5000 has a noise floor that is

effectively absent.

The Allnic L-5000 DHT preamplifier is THE WORLD'S FIRST

COMMERCIALLY PRODUCED, PURE DHT PREAMPLIFIER.

Currently, the L-5000 DHT's large output tubes are very

rare items, produced many decades ago. Allnic has been

able to secure a limited number of these valves, enough

to produce an also limited number of the L-5000 DHT

preamplifier. ONLY A LIMITED NUMBER OF UNITS OF THIS

DESIGN WILL BE MADE. This allows for valve stock to be

Mr.Park has succeeded in

reduces the