|Leak Varislope II
The manual available with this Varislope II pre-amplifier is dated August 1954, however this model may have been available sometime prior to this. The unit shown photographed here was part of a sound installation for the live stage show "Kismet" which ran in Melbourne, Australia during the mid 1950's at the Princess theater. As far as can be determined, the full sound installation featured 7 Varislope II pre-amps, six TL/25A power amps, and one TL/12. (The unit shown was is quite poor condition pysically, but "Photoshop" imaging software makes it look new here!).
As with all Leak pre-amps, there are two gain stages each with shunt feedback. The first stage performs any required equalisation, and the second stage performs tone control and variable-slope high frequency filtering.
This pre-amp features higher input sensitivities than previous pre-amps, and has improved appearance. Two EF86 valves are used, with a similar shunt feedback circuits as used in previous pre-amps. The disc equalisations provided are: BRIT-78, BRIT-LP, COL-LP, RCA-Ortho, AES and NARTB. Tuner, Tape, Mic and Auxilliary inputs are also provided. Bass and treble are switch boost and cut, with the variable slope facility available for treble-cut. Steel front panel finished in gold enamel. Mono only.