Thread: Holden/wasp guitar amp

hi guys, ive picked up a late 60's/early 70's australian guitar amp. its a 200w holden wasp. its a great sounding amp (after i cleaned 20 years of grime out of the scratchy pots, now their great). its a nonmaster volume amp, but channel one gets some nice crunch, channel 2 is beautifully clean. the amp runs on 4 6550 power tubes and 4 12ax7's. there are 2 12ax7's in the preamp, 1 for the phase inverter and then a 4th as a post PI boost. probably to realise the full potential of the 6550's which are low gain compared to most power tubes.

i am going to have a look at the circuit when i finish my uni exams (the end of this week) and see about drawing up a schematic. ive sent an email to the guy from www.ozvalveamps.elands.com with some info and pics of the amp, and will probably send some more info over when i get the schematic drawn. the amp has 2 channels, with 2 inputs each (dont think there is a difference in gain between the inputs on the same channel, if there is it is minimal). there is a volume for each. there is a bright switch in the form of a push pull pot on the channel 2 knob (works on both channels). there is a 3 band eq, as well as a presence knob.

the amp is on a circuitboard, but all is well spaced, so it shouldnt be too hard to repair if necessary.

soundwise, its great. nice and punchy, with some crunch on channel one that works well. the cab has 4 rola/plessey 12u50 speakers, which sound great.

here are some pics













got it for a steal, and am very happy with it.