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| L10 Line Stage Pre-amplifier | ||||
| Following the positive response to our flagship L300 pre-amplifier, pure sound has developed the L10, a new, more affordable design which incorporates much of the thinking that makes the L300 so highly regarded. The L10 has 4 inputs, a separate passive Record In Record Out loop and two pairs of single ended outputs. The circuit uses output transformers and a sophisticated full valve rectified, twin choke smoothed power supply. It also offers remote control of the volume via a separate handset. | ||||
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| In the L10, source selection is via a high quality switch located near to the input sockets. The chosen source is routed to a high quality motorized, film potentiometer and from there on to the audio circuit. This consists of a single ended triode stage loaded by a custom wound wideband output transformer which steps down the amplified signal allowing it to be coupled to the power amplifier at a manageable level and as a low impedance source. The output stage of the L10 is impervious to long interconnecting cables or lower impedance power amplifier input stages. | ||||
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| The L10 also incorporates an extremely sophisticated power supply to maintain constant operating conditions for the audio circuitry. It includes a valve rectifier, and a twin choke filtered LCLC stage which provides a stiff, voltage rail allowing the audio circuit to operate in a calm and orderly way regardless of the demands the music makes on the amplifying stage. Filament supplies are fully regulated to further reduce the potential for noise. | ||||
| M845 Mono Power Amplifier | ||||
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The
pure
sound M845 mono power amplifier is a single ended design based around the 845
power triode. Operating in Class A and giving 27 Watts
of output power, it will complement a wide range of medium to high
efficiency loudspeakers. The 845 triode was originally developed by RCA in 1931 as a radio transmitting and audio amplification valve. The anode is machined from solid graphite to allow high power dissipation. It has an extremely linear transfer characteristic. In recent years, a renewed interest in this kind of valve has resulted in them being manufactured again by various factories in China. Implementing the 845 in a sympathetic circuit which takes full advantage of its capabilities is not straightforward. The filament draws a significant amount of power and also forms a part of the signal path so energising it correctly is a critical part of the design. The valve also operates with very high voltages across it so again, a careful choice of filtering components for that high voltage supply is essential such that adequate current is available to the valve at all audio frequencies instantaneously. In the M845 this supply includes a hybrid Graetz bridge for the initial rectification and a substantial smoothing choke as part of its CLC type filter. |
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Although
all of the elements; power supply, circuit topology & component choice
have a profound effect on the overall performance of a valve amplifier,
one of the most important aspects is the design & construction of the
output transformer. A high primary impedance, the resultant large step
down ratio and the need to maintain a high level of insulation between the
windings all conspire against the transformer designer and the quest for
extended bandwidth with efficient power transmission. The M845 utilises an
in house designed output transformer that underwent extensive trials using
a variety of core materials and winding techniques before the final
configuration was chosen. The other difficulty in using the 845 is in the design of a stage capable of cleanly delivering the voltage swing necessary at its grid to take it to full output. The M845 incorporates a driver stage based on the 6SN7 triode coupled via a custom wound, wideband, interstage transformer. The amplifier’s input stage is directly coupled to this driver meaning that there are no coupling capacitors used in the circuit at all. The circuit also operates without any negative feedback. The end result is an amplifier capable of reproducing the full measure of instrument tone with extraordinary dynamic contrast, energy and colour. When partnered with appropriate loudspeakers the M845 will deliver an unparalleled reproduction of all types of music. |
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| A10 Line Integrated Amplifier | ||||
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The A10 is a small line integrated amplifier from pure sound. Operating in Class A and delivering 10 Watts per channel it is intended for users of high sensitivity loudspeakers or for those seeking high performance with small speakers perhaps in a bedroom or study. The A10 accepts two line level inputs and may be switched to drive 4 or 8 ohm loudspeakers. The circuit is based around the sweet sounding 6P14, a modern equivalent to the EL84 / 6BQ5 family. |
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| A10 Line Integrated Amplifier | Download PDF (398KB) | |||
| Read a review in Hi-Fi Choice April 2010. | ||||
| L300 Line Level Pre-amplifier | ||||
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| Following some fairly extensive r&d applied to line level amplification, pure sound have launched the L300 line level pre-amplifier. L300 has 5 inputs and twin outputs (2 pairs single ended and 2 pairs balanced via XLR). The circuit uses output transformers and a sophisticated full valve rectified, choke smoothed, regulated power supply including a 300B triode as the series element. | ||||
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| L300 Line Level Pre-amplifier | Download PDF (425 kB) | |||
| Read a review in Hi-Fi + issue 73 | ||||
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| The
pure sound A8000 CD Player was developed as a high quality source to be used with
the pure sound range of amplifiers. It
can also be used in a wide range of other systems with great success. |
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| The
A8000 is built around the SONY 213Q high precision mechanism, renowned for both
its stability and reliability. A
proprietary 24 Bit 192KHz D/A converter handles the data stream, which, once
converted, is filtered using OPA2604 Op amps. The powerful output stage
comprises a pair of 6N3 double triodes. Signal coupling here is via MIT
capacitors while the output stage power supply utilises the German MCap
capacitors. |
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| The incoming mains supply is filtered by a choke regulated circuit which in turn feeds 8 separate regulated supplies each of which uses Silmic and Rubycon capacitors. These deliver power independently to various parts of the circuitry. | ||
| At
switch on, the CD Player counts down for 20 seconds to allow the valve circuitry
to warm and stabilise before the machine can be used. |
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| The
substantially constructed chassis includes a 10mm anodised aluminium front
panel, high quality gold plated RCA sockets for L-R and digital outputs. |
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remote control is a sleek, anodised design machined from solid aluminium. |
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| Many
CD Players using a valve output stage have an overly euphonic, almost
‘syrupy’ quality, which compromises the reproduction of detail and drive.
The A8000 has no such obvious characteristic.
However, it does reproduce instrument timbre and dynamic range in a
plausible way providing a lively yet unfatiguing presentation of music not
dissimilar to that, which can be heard at a live concert. |
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| The CD Player itself comes with a three
year non-transferable warranty. The warranty on the valves is 6 months. |
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| A8000 CD Player | Download PDF (173KB) | |
| Read a review in Hi-Fi + issue 50. | ||
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| The Hi-Fi+
"2006 Discovery Product of the Year" and Hi-Fi
Choice "Best Buy" 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. |
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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. |
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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. |
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The
output can be configured for use with 4 or 8 ohm loudspeakers. |
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| The pure sound 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. | ||
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The amplifier itself comes with a
3-year non-transferable warranty. The warranty on the
valves is 6 months. |
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| A30 Line Integrated Amplifier | Download PDF (226KB) | |
| Read a review on 6 moons website | ||
| Read a review in Hi- Fi News June 2009 | ||
| Read a review in Hi- Fi World June 2009 | ||
| Read a review in Hi- Fi + Issue 52 | ||
| Read a review in Hi- Fi + Issue 50 | ||
| Read a review in Hi- Fi + Issue 48 | ||
| Read a review in Hi-Fi Choice October issue | ||
| Read a review in Hi-Fi Critic issue 6 | ||
| 2A3 Line Integrated Amplifier | ||
| The pure sound 2A3 is an 18 Watt per channel 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. | ||
| The pure sound 2A3 amplifier features an unusual choke loaded driver stage which allows the 6SN7 driver valves to deliver the full measure of signal to the push/pull output valves. This rather exotic configuration usually results in a tremendous depth to the tone of instruments and the Pure Sound 2A3 is no exception in this regard. | ||
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| 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 pure sound 2A3 may also be used as a very high quality stereo power amplifier if the volume control is turned up fully. | ||
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2A3 Line Integrated Amplifier |
Download PDF (72kB) | |
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| P10 Phono Amplifier | ||
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The P10 phono amplifier is intended to meet the requirements of audio enthusiasts who still enjoy the distinctive strengths and high quality of reproduction that can be derived from vinyl records. It is compatible with moving magnet and high output moving coil cartridges. |
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| The P10 phono amplifier meets the very strict performance criteria required of all pure sound products and will give excellent results with vinyl records provided that it is used with appropriate ancillary equipment. | ||
| P10 Phono Amplifier | Download PDF (430 kB) | |
| Read a review in Hi-Fi World February 2008 | ||
| Read a review in HFN & RR March 2010 | ||
| T10 Step Up Transformer | ||
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The T10 transformer has
been introduced to allow the pure
sound P10 Phono amplifier to be used
with moving coil cartridges. It has been our experience that the best
results are achieved when using moving coil cartridges loaded via a
correctly matched transformer. The pure
sound Impedance Matching
Transformer T10 contains two wide bandwidth, custom manufactured
transformers with MuMetal cores. These have a natural unloaded ratio of
15:1. The T10 also includes
the provision to alter the load seen by the cartridge. It allows different
secondary load resistances to be placed across the secondary winding of
each transformer. These, acting in parallel with the load resistance
(typically 47Kohms) of a phono stage are reflected through the transformer
to the cartridge. An optimum loading for the cartridge chosen can be
readily found by ear. |
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| T10 Step Up Transformer | Download PDF (636 kB) | |
| Read a review in HFN & RR March 2010 | ||