Pure
Sound A30
integrated tube amplifier
The pure sound A30 amplifier was developed to
meet the demand for an affordable Class A amplifier
that would be compatible with all types of loudspeakers.
The A30 is a line level integrated design that
allows for the selection of up to 3 different
source components and control of the volume
by a high quality ALPS Blue Velvet potentiometer.
Class A operation was chosen because it gives
lower distortion and a more relaxing, natural
sound.
The
amplifier uses the very robust Electro Harmonix
6550 output valves in an Ultra Linear Push Pull
configuration. This arrangement gives a combination
of power and clarity that is difficult to beat.
The amplifier uses an Auto Bias system, which
means that replacement output valves should
be fitted as matched pairs. There will be no
need to reset or monitor bias conditions.
Very
high quality components are used throughout
including selected carbon film resistors and
SCR polypropylene capacitors. The power supply
makes use of twin valve rectifiers and choke
smoothing.
The
output can be configured for use with 4 or 8
ohm loudspeakers.
The
output stage can also be switched to triode-coupled
configuration. This further linearises the operation
of the valves at the expense of some output
power. It may be preferable with higher sensitivity
loudspeakers.
The
A30 may also be used as a very high quality
stereo power amplifier if the volume control
is turned up fully.
When
partnered with appropriate ancillary equipment
the A30 is capable of very satisfying performance.
Why this amplifier? Why now?
With
the recent interest in lower powered Single
Ended triode amplifiers has come the realization
that to get the best from these, the speakers
used have to be both sensitive and quite large
to give truly satisfying results. There are
also not that many good, high sensitivity (>97
dB/W) designs available at any price never mind
at price levels the majority of music lovers
can afford.
However,
there are some very good loudspeakers currently
being made with sensitivities between 88 and
94 dB/W. These are sufficiently revealing to
make the virtues of simple, high quality amplification
readily apparent, although in most cases the
output of a typical single ended amplifier is
insufficient to give the scale and drama many
types of music demand.
A
good amplifier with 25 -30 watts of output power
is more than enough to drive this type of loudspeaker
to sensible levels even in quite a large room.
For simplicity a valve amplifier is preferable.
Recently, there has been an increase in the
number of relatively affordable valve amplifiers
made in China. Many of these are compromised
by the quality of their transformers, components,
layout and because they operate in Class AB
or B to give a higher power specification. They
often also use a lot of negative feedback in
an attempt to compensate for these shortcomings
with a consequential impact on clarity and low
frequency control.
For
some 10 years there has been a lack of affordable
Class A valve amplifiers.
The
pure sound A30 operates fully in Class A up
to its rated output so it does not change character
at any signal level. There is none of the distortion
caused by output devices switching on and off
and therefore no requirement for excessive feedback
to correct for it. The 6550 valves supplied
are the extremely robust Russian Electro-Harmonix
variety and are quite content with dissipating
the power required to maintain Class A operation
up to 30 Watts.
The
valve rectifiers used keep the high voltage
power supply clear of the noise that can be
introduced by silicon rectifiers. A substantial
choke is also incorporated to keep the power
supply impedance low.
The
output transformers also give extremely wide
bandwidth allowing very solid low frequency
performance as well as exceptional reproduction
of timbre.
These
design features combined with the use of high
quality passive components, octal based input
and driver triodes and an elegant but simple
internal layout results in an amplifier which
sets a new benchmark for performance, build
quality and value.
Features
Class
A operation
3
Line level inputs
30
Watts per Channel Output
4
and 8 ohm output taps
Twin
valve rectifiers
Choke
smoothing
ALPS
potentiometer
SCR
coupling capacitors
Carbon
film resistors (for better sound quality)
Electro
Harmonix (Russia) 6550 output tubes
Very
substantial construction including cast metal
transformer shrouds.
Product
Review:
HiFi+
issue 48
The Pure Sound A30 amplifier earned a 'Product
of the Year' award in issue 48 of HiFi + magazine.
Alan
Sircom in HiFi+ issue 48 :
Sonically
there's nothing to touch its combination of
musical integrity and authority at anything
like the price.
Hifi
+ issue 52
Chris
Thomas in HiFi+ issue 52:
The
Pure Sound performed so incredibly well that
I completely forgot that I was listening to
an amplifier that costs a little over a £
1000. Where
this amplifier scores is in its impressive musical
coherence across the bandwidth.
The pure Sound positively drips with the ambience
of the event and has a musical presence and
range of tonal colours that sets it apart from
the crowd.
HiFi
Choice (pdf-file)
Black magic, Pure Sound`s first amplifier
is able to cast a spell its listeners
AUDIO
Sept. 2007
AUDIO Prädikat:
überragend, 100 Punkte, High End Klasse,
5 Ohren.
"Prachtvoll aufgebaut und bestückt,
extrem feinsinniger, farbenreicher Klang"
Price
:
(including 19% VAT)
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