Recently I managed to score a real bargain. A non-working Vox AC10C1, certainly out of my available cash price range in full working order, but the cabinet looked good to revisit my intention to build an original AC4 style amplifier complete with EF86.
It arrived missing the power switch and having suffered a little bending to the metalwork having not been reassembled in a way that supported the L-shaped chassis, but after a quick dab around the chassis with a test meter it appeared intact bar the 'eco' board. Without getting into all the political debate going on about the EU, this is one of those well-meaning attempts to make the world a better place that doesn't quite work out. The function of this board is to power the amp down after 2 hours of no signal - which is kind of pointless really... yes on a TV, yes on a laptop, on a guitar amp? Nah...
So out it came.
A new set of valves went in from Ampvalves - (if the AC10C1 is not added yet you can use the Orange Tiny Terror 2xECC83, 2xEL84 set) - and the sound was there, although very quick to distort and surprisingly quiet. A second dab around with a test meter revealed 6V on the anode of one of the EL84's and a whopping 21K resistance on that connection on the output transformer.
The AC10C1's transformer is a tiny shielded generic unit which isn't really obtainable at a sensible price, so looking for a suitable alternative I ordered a Marshall 18W OT from AmpMaker. Being open it does pick up a little hum, and with its higher rating doesn't break up on the power section as early but wow, what a sound now its up and running!
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