The 250 'Laboratory' mono power amplifier was an updated version of the earlier 240 model and was designed for use with Scott's 130 stereo preamplifier (obviously in pairs). The 240's 70 volt output taps and variable damping control were dropped for the 250, but bias test terminals and a 'floating' front panel was added. Power output was 36 watts RMS (40 watts music power and 80 watts peak) with less than 0.5% harmonic and 0.1% IM distortion. Scott advertised this amplifier as having 'our famous Power Balance output circuitry that assures lowest distortion at ANY listening level. Noise and hum were 85dB below full output and a frequency response of 12 cps -60,000 cps was claimed.

The 250 had dual-level inputs of 0.5 and 1.5 volts  with level control and the circuitry employed five valves: two 12AX7 (floating para-phase inverters with an AC balance pot); two x EL34/6CA7 (output) and one 5U4GA (rectifier).

A rack-mounted version of the 250 was also marketed by Scott's Instrument Division for professional use.

Priced at $129.95 when new, today's value would be around $250 - $350 for a well-presented, working example and possibly up to $500 for a pristine or restored one. Recently, a pair of 250s in shabby condition, untested and without output valves sold on internet auction for $375.

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