5 W Amplifier B5

Type B5 Amplifier

The output from the tuner chassis feeds the MHL4 which is RC coupled to the PX25. The coupling arrangement is conventional. The anode load is calculated for freedom from distortion rather than stage gain. The coupling condenser is of the mica type. Decoupling arrangements by resistance and 8 µF condensers.

The output transformer is 93% efficient and is tapped for one or two Voigt speakers.

Mains equipment is very liberal in its design and complies with various regulations, fuses being fitted on both primary and secondary windings.

A buffer condenser tested at 2,500 volts is fitted across the mains input to minimise modulation hum and interference from rough mains.

High inductance chokes together with surge-proof electrolytic condenser 8 µF deal with the smoothing.

Sixty volts are dropped in the negative line as model A12 to enable our ADT tuner to be used with this amplifier.

Whilst the hum is not quite so low as Model A12 it leaves very little to be desired, even when used with Vougt Corner Horn which is now efficient down to 40 cycles.

This amplifier can be supplied with a feeder stage to enable it to be used solely as a gramophone amplifier, its output being sufficient when coupled to a Voigt unit and 4’ horn to fill a thousand-seat hall.

Specifications

Power Output 5 watts approximately.
Output for radio tuner: 300 V, 40 mA, and  4 V, 8 A

Here you find 56 models, 51 with images and 2 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Lowther Manufacturing Co; Kent