|Leak TL/12 Plus
Introduced around 1956, this amplifier replaced the TL/12. The amplifer is a lot smaller physically than the TL/12, as it used the new "9-pin" power valves in the output stage configured in "ultra-linear" mode instead of the inefficient but very linear triode-connected KT-66's of the TL/12. Power output was 12 Watts, and distortion 0.1% of course.
The output transformer secondary was wound as one winding with taps at
the relevant places for 4, 8 and 16 Ohms, in contrast to the TL/12 which
had for separate secondaries which could be configured for various loads.
The power supply uses electrolytic cpacitors, and the small filter choke
in the TL/12 circuit was replaced with a much cheaper 100 Ohm / 5 Watt resistor.
Other circuit toplogy remained basically similar to the TL/12. The Stereo
20 is basically a stereo version of this amplifer.