The X-20 was much better than
its precessor: it was putatively rated at 20 watts and
it would indeed deliver 20 watts, but only with its
dying breath, for the output transistors that arrived
for manufacture were somehow never as good as the prototypes
supplied for development. In any case, Sinclair already
had a 10W amplifier: the new one obviously had to be
better because it was more expensive! Apart from this,
the X-20 was a good amplifier. There was none of the
unpredictable performance of the X-10,
no two of which ever behaved in quite the same way.
Later - just about the time at which the X-20 was discontinued
- larger output transistors became readily available.
Some of these were tried in the X-20 and it gave 20
watts without the slightest troubles or sign of distress.
The X-20 was heavily trailed in advertisements through
the summer of 1965, with double-page spreads trumpeting
"in step with the SPACE AGE!" in rather wobbly
lettering backed by a drawing of the Post Office tower.
Only a year old and 619 feet high, the tower symbolised
London's step into the space age; not only did it handle
satellite communications (indirectly); it had a revolving
restaurant. The adverts declared that the X-20
OUTDATES EVERY HI-Fl
AMPLIFIER TO DATE
The Sinclair X-20 enables you to enjoy
for the first time ever, the advantages of using a
high power, high fidelity audio amplifier truly in
step with today's space age electronics . . . and
it is easier to build and install than any amplifier
you have ever owned. Best of all it costs far less.
Power supply: £4.19.6d