Philips Australia Amplifier Type 961.

Serial Number 3486.  Two microphone and one P.U. input channel PA amplifier.  9-pin pentode amplifier for each microphone channel, and for summing amplifier. 6SN7 splitter and fixed bias push-pull pentode output, with secondary side feedback.  Plate supply from half-wave voltage doubler 5U4GB (2x) diode rectifier and capacitor filter, inductor feed to the screen supply, and resistor dropping to the driver circuit supplies.  Output stage grid bias from separate half-wave diode supply (can't determine valve type used). Bass & Treble tone pots between summing and splitter stages.  5x 8-pin Octal and 4x 9-pin Novel bases total.

Power and output transformers with markings but no manufacturer.  Choke from Plessey.  POTs are IRC but only BD2 or RC2 markings.  Ducon caps.  The 20uF is DUCONOL A.  330V secondary will likely supply about 800V to output stage.

Modified over the years: voltmeter on cover; most supply rail caps bypassed; extra P.U. input added and associated volume pot added to front panel.

All transformer windings and choke show good Megger readings.  However the amplifier was not powered up in original circuit due to condition of all caps.  The amplifier is presently undergoing a complete rewire, with the circuit changing to guitar amplifier use.
