World Audio Kel 80 Instruction Manual - page 3
INTRODUCTION
KEL 80 monobloc is an inexpensive valve monoblock amplifier capable of providing no less
than 80 watts into an 8 ohm load. This is enough power to satisfy those who feel the usual valve
amp power of around 20 watts insufficient for their needs. The KEL 80 operates in Class AB, run-
ning in Class A at low signal levels to ensure distortion does not colour music at ordinary volumes. It
is possible to bridge two monoblocs by paralleling the inputs and outputs, this delivers an amazing
160 watts into a 4 ohm load.
The KEL 80 uses a ultra quiet encapsulated toroidal mains transformers and a large high
quality E/I output transformer to achieve a broad frequency response that will not waver even at full
power. All valves, rectifiers and the passive components are mounted directly onto the large printed
circuit board, thus improving ease of build compared with its hard-wired counterparts.
The circuit is similar to our popular KEL34 in that it uses the venerable 6AU6, directly cou-
pled to a common cathode phase-splitter, the high power, high transconductance 5687. The output
stage is four EL34 from Tesla (J.J. branded), in parallel push-pull
Simon Pope HFW editor says, “The KEL 80 manages to combine tube refinement and brute
power in a two-box package. Opening with some classical tunes, the KEL80s brought out the depth
of the orchestration as only valve amplification can, crisp, solid bass and lightning-fast transients
coupled with an addictive smoothness to precussion and violins. It takes an amp with genuine con-
trol and grunt to bring out the full bass potential of `Mindfields`, and the KEL80s were well up for the
job. They succeeded in reproducing that rare bass `bounce` that is rarely found in valve gear and
almost never in solid state.”
At this price, the amp is second to none and will open up the benefits of valve amplification to
all you high power audio nuts.
MEASURED PERFORMANCE
power................................................................78watts into 8 ohms
frequency response.......................................................24Hz-96kHz
separation.................................................................................60dB
noise......................................................................................-110dB
sensitivity..............................................................................400mV
distortion........................1kHz..1 Watt..0.012%....78 Watts..0.36%
distortion........................10kHz..1 Watt..0.1%........78 Watts..1.2%
SKILL LEVEL
To build this amplifier you must be able to:
a) solder.
b) have some knowledge of valve circuitry.
c) possess a rudimentary understanding of electricity and electronics.
e) have a multimeter and be able to use it.
f) have access to a dummy load or an old pair of speakers.
g) know the precautions necessary to avoid electric shocks from the mains and amplifier
power lines.
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KEL80 instructions 27/3/00 10:44 am Page 3