Audio Valve BALDUR 70, Инструкция по эксплуатации

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BALDUR 70
BALDUR 70
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triode tube power monoblocs___________
triode tube power monoblocs___________
2. Background to the BALDUR 70
In 2003 at the CES show in Las Vegas AudioValve’s customers and dealers made it
abundantly clear that there was a requirement for a smaller version of the BALDUR 200
plus. Ideally this would offer the same sonic excellence as the 200 plus but in a smaller,
less expensive package.
AudioValve’s answer was the ‘baby’ BALDUR 70 Class-A triode monoblock power amplifier.
The development of a baby BALDUR was rapid with its world premiere being at the ‘High-
End-Show’ in Frankfurt-Germany later the same year! It achieves within a ‘whisker’ the
ideal that the customers and dealers wanted. As you rarely, if ever, get something for
nothing, some compromises had to be made, but these were surprisingly few.
The BALDUR 70 uses half the complement of 6AS7G valves of the 200 plus which in turn
halves power output to 75 watts per channel - still more than enough power to satisfy the
vast majority of users and at a significantly lower cost!
Damping factor is also reduced from the amazing 100 of the BALDUR 200 plus to
20 for the BALDUR 70. Nevertheless, this is a class leading performance,
as the damping factor of competing valve amplifiers is not their strongest feature.
This combination of power and damping factor means the BALDUR 70 is happy
driving a wide range of loudspeakers whether dynamic, electrostatic or hybrid types.
The high damping factor ensures strong, clean, taut and sharply outlined bass
accompanied by a broad, deep soundstage and delicate, ‘velvety’ high’s that can only be
obtained from pure triodes amplification.
There is a clear family resemblance in the appearance of the two BALDURs. The 70
incorporates all of the design and constructional elements of its bigger brother and
retains the Audio Valve hallmarks of safety, reliability, durability, low maintenance and
ease of use that are familiar to all owners of AudioValve products since the first amplifier,
the RKV, was launched over 20 years ago.
3. The 6AS7G Valve and ABR circuit
The BALDUR 70 uses four 6AS7G dual triode power output valves. This valve was first
used in the BALDUR 100 and is also used in the current BALDUR 200 plus. The 6AS7G
is an exceptionally high performance triode when it is working optimally. However
there are too many adjustments that need to be carried out for optimum performance to
be maintained over time using a conventional biasing circuit. As a consequence the
valve is rarely used and is relatively inexpensive.
Traditionally, valve biasing is performed with a screwdriver to adjust the bias current to
the valve. Any such adjustment can only be optimum for an instant as valves,
even selected ones or a matched set, cannot hold a consistency of performance in
the long term. Each valve will deteriorate individually and, if in a set, not necessarily in
the same way as others in that set. A matched pair or quad will therefore only remain
matched for a relatively short period of time!