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
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.
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.
output can be configured for use with 4 or 8 ohm loudspeakers.
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.
A30 may also be used as a very high quality stereo power
amplifier if the volume control is turned up fully.
partnered with appropriate ancillary equipment the A30
is capable of very satisfying performance.
Why this amplifier? Why now?
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.
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.
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.
some 10 years there has been a lack of affordable Class
A valve amplifiers.
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.
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.
output transformers also give extremely wide bandwidth
allowing very solid low frequency performance as well
as exceptional reproduction of timbre.
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.
3 Line level inputs
30 Watts per Channel Output
4 and 8 ohm output taps
Twin valve rectifiers
SCR coupling capacitors
Carbon film resistors (for better sound quality)
Electro Harmonix (Russia) 6550 output tubes
Very substantial construction including cast metal transformer
Rene van Es, Februari 2009
"In de inleiding vroeg ik mij af, of alwéér
een buizenversterker wel nodig was en of mijn Engelse
collega’s de waarheid spraken. Over het eerste
standpunt valt te twisten, met het tweede ben ik snel
klaar: ze hebben gelijk. De A30 versterker is niet alleen
esthetisch mooi, hij speelt eveneens heerlijk."
The PureSound A30 amplifier earned a 'Product of the
Year' award in issue 48 of HiFi + magazine.
Sircom in HiFi+ issue 48 :
there's nothing to touch its combination of musical
integrity and authority at anything like the price.
+ issue 52
Thomas in HiFi+ issue 52:
PureSound 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
colors that sets it apart from the crowd.
Choice October 2007, (pdf-file)
Black magic, Pure Sound`s first amplifier is able
to cast a spell its listeners
überragend, 100 Punkte, High End Klasse, 5 Ohren.
"Prachtvoll aufgebaut und bestückt, extrem
feinsinniger, farbenreicher Klang"
News, June 2009, (pdf-file)
The A30 fares very well in a group test of valve amplifiers
featured in the June 2009 issue of HiFi News. These
amplifiers were from a very broad price range and as
one of the least expensive designs the A30 was felt
to offer very good value. It was one of two of these
amplifiers to earn a 'Highly Commended' rating.
"..it had that tremendous presence through
the midband that, unlike the other amps, brought the
orchestra right into the room."
World, June 2009, (pdf-file)
A30 received another favourable (if peculiar) review,
this time in the June 2009 issue of HiFi World. The
reviewer mistakenly spends rather too long on the issue
of amplifiers designed around KT88's (which the A30
deliberately does not use!) but his subjective experience
of the amplifier is very positive.
"..the A30 is an amplifier of enormous sophistication.
It sets up a wonderfully rich picture of a performance
that is full of lively fine detail free from any form
of edginess, yet fluid in its progression and both easy
and natural to the ear."
+ issue 64, (pdf-file)
excellent review of the A30 amplifier coupled with a
Border Patrol power supply has appeared in issue 64
of Hi-Fi Plus.
In February 2010 the online magazine 6 Moons published
a very positive review of the A30. You can read this
review by clicking the link above.
Sound A30 NL version
Special NL version with upgraded Copper foil coupling
capacitors, Amtrans and Shinkoh resistors.
The factory that makes the A30 also makes the Bewitch
There is a Bewitch amplifier that looks just like the
Pure Sound A30. The Bewitch 6550 is a 60 Watt Class
AB amplifier which uses reduced bias current (hence
it is a Class AB amplifier and can deliver more output
power), different (smaller) output transformers and
a different feedback circuit.
All Pure Sound branded products are made to our specifications.