PLAYMASTER: Model 102 Guitar Amplifier

From Radio, Television and Hobbies, October 1962

PLAYMASTER MODEL 102 SINGLE-CHANNEL GUITAR AMPLIFIER

PLAYMASTER: Model 103 Guitar Amplifier

The Playmaster is an Australian twin channel guitar amplifier from the sixties - these came in kits, with instructions published in a magazine.  It's an usual design if you're used to looking at Fenders and Marshalls etc.  

Channel one:  The main guitar channel has volume, bass, treble, vibrato speed and depth and has 12" speaker.  The 12" speaker directly drives the reverb tank - more on that below.  This channel on its own is similar to the Playmaster 102 guitar amplifier.

Channel two:  Channel two is an entirely separate amplifier, with its own 10" speaker.  Controls are volume and tone.  The reverb tank can be plugged in via a jack, or it can be used a separate channel for a microphone or record player (the old high-output type).

So there are two completely independent 12w channels.  Each channel has an identical output transformer, phase inverter and power amp.  The power amp stages / transformers are both ultra-linear, which is a little usual in itself.  The preamps also vary to account for different uses.

Valves: 6GW8 pentode / triodes.  7199 triode / pentode for preamps and a 6BE6.

PLAYMASTER 103 GUITAR AMPLIFIER

Original article from Radio, Television and Hobbies, January, 1963

FERGUSON OPM7A OUTPUT TRANSFORMER SPEC

PLAYMASTER: Model 103, Two-channel Guitar Amplifier

PLAYMASTER MODEL 103 GUITAR AMPLIFIER 

From Radio, Television and Hobbies (Australia), 1963.  They published their designs for a number of amplifiers in their magazine under the Playmaster name.  

This was a pretty interesting DIY amplifier for back in the day - speaker driven reverb, trem and ultra-linear output transformer.