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Instruction Manual Covering:
Stereo 25 MK II
Ultralinear Push Pull Amplifier EL34 or KT88
Standard version with KT88s
Contents
1 Introduction & Final Inspection
2 Quick Set Up Guide
3 Connecting inputs & outputs
4 Getting the best performance
5 Trouble Shooting
6 Bias Adjustment, Triode mode
7 Valve Replacement
8 Specifications
9 Guarantee
10 Packing Instructions
1 Introduction
Thank you for purchasing the
Stereo 25
.
A great deal of care has been taken in the design,
selection of components and production of this
amplifier. We are sure that you will hear the
difference.
In order to get the best out of your amplifier,
please read the enclosed notes. Even if you are
experienced with hi fi
please read
the ‘quick set
up guide’.
Should you be uncertain about
anything to do with your amplifier please contact
us for advice.
Hi fi reproduction is a long chain of events that
includes the recording, editing, mixing etc, before
being transferred to a medium such as LP, CD, or
FM, before being played through your own source
unit, the amplifier and finally loudspeakers.
Your room acoustics will also affect the sound
before it finally reaches your ear. Whilst the
amplifier is arguably the most important part of a
system, it is important to remember that the
weakest link will always affect the final results
when making judgements. And not all recordings
are have a good
“balanced” sound, therefore an
amplifier which faithfully reproduces the input
signal will also reproduce imperfections in the
tonal balance and the recording itself. Setting up
and judgements should be made with a ‘clean’
well balanced recording.
The
Stereo 25
is a push-pull Ultralinear
stereo power amp, capable of running in
Ultralinear mode (half pentode and half triode).
Using the excellent 6L6/EL34/6CA7/KT66/KT88
valves. These are in semi auto-bias mode which
whilst rarely requiring attention gives maximum
power, cool running and wear indication. The
driver and phase splitting is all triode for best
sound quality and low noise. The pre-amp is a
high quality ‘Passive’ circuit using silver PTFE
audio cable and an ALPS
‘blue’ volume control. It
is sensitive enough to be used with all modern
source equipment having an output of 300mv or
greater. It may also be used as a power amplifier
being driven by a separate pre amplifier. Its
simplicity coupled with point to point hand wiring
without the use of printed circuit boards results in
an open euphoric sound that is wonderfully
detailed and warm sounding. The overall design is
inspired by the Leak Stereo 50 design. The wide
range of output valves that ST25 is capable of
using make it extremely versatile and you can
customise it to your own taste. Recommended
upgrades are Mundorf capacitors and various
output and driver valves.
IMPORTANT!
THIS MANUAL CONTAINS
ESSENTIAL INFORMATION
FOR THE HEALTH & SAFETY
OF YOUR AMPLIFIER. PLEASE
READ & KEEP SAFE AND
REFER TO IF NECESSARY
