It’s been a while, life got, well lets just say life got….
In the meantime I came across some cheap l-pads on ebay which set me thinking about building a quick and dirty attenuator for my Harley Benton Ga5H, (its an dpi valve junior copy).
An L-pad is basically a big variable resistor with enough welly to act as a load dump between a low wattage guitar amp and a speaker. The ebay ones are rated at 12 watts, as a rule of thumb I would suggest using a pad that is rated twice as high as your amps output. My Ga5h is rated at 5 watts so 12 watts for the l-pad is fine.
The schematic is stupidly simple. I didn’t even bother with a switch in the end. The thing rolls a lot of treble off when in soaking up a lot of power. You could freak about with resistors to add treble back into the signal.
It works ok.