World Audio Kel 80 Instruction Manual - page 2
SAFETY WARNING
Lethal voltages exist in this amplifier. Even though this is one of our simplest kits, in terms of
construction, please do not attempt to build it unless you have some understanding of valve circuitry
and can follow safety precautions.
We do provide a back-up service, a help-line is manned from 9.00am to 5.00pm Monday to
Friday, should you run into any problems. Additionally, if the worst comes to the worst and you
encounter problems, ,we will get you amplifier up and running, for a nominal charge .
For safety, never hold earthed metal work when testing. Make sure your body is isolated by
rubber soled shoes. To aid construction use a voltmeter, one capable of reading up to 1000 volts
would be adequate. YOU MUST WEAR THE RUBBER SAFETY GLOVES PROVIDED when test-
ing, since the greatest danger comes from a slip at this time. Always remove the mains plug when
you are soldering after switch on. The larger power supply capacitors will hold a charge after switch
off, so continue to wear your gloves at all times when working internally.
Additionally be aware that the valves do get very hot and will burn skin on contact, therefore
please position in a safe place, away from children and animals. Due to the compact size of the
amplifier the chassis`s top surface does get hot and the front panel will be warm to the touch.
FUSE
This amplifier consumes 1A from the mains and must be fitted with a 1.6A SLOW-BLOW
fuse. If this blows, then there is a fault and it must be cleared before another fuse is re-inserted. Do
not use a higher rated fuse as you may burn out your transformers and always use the slow-blow
type.
OUTPUT TRANSFORMERS
When it comes to switch on you should always have your output transformers connected up
to a 8 ohm or a 4 ohm load, depending on which taps you have wired up, be it a dummy load (high
power resistor) or a pair of speakers. This is because the load is an integral part of the circuit, unlike
most transistor amplifiers. Switch on without a load will cause unnecessary distress to the output
transformers and failure if left in this state for a long time.
READING
Before you start building read through the instruction at least twice to avoid any mistakes.
All rights to the design are held by World Audio Publishing Ltd. No part of this manual may be
reproduced without Copyright permission from the Company. The kit is for private constructors only.
It is not to be re-sold or in any way used for commercial gain or profit without express written per-
mission from World Audio Publishing Ltd.
World Audio Publishing Ltd.
Imex House
Kilburn Park Rd
LONDON NW6 5LF.
HELP-LINE 0171 625 8032
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