@ James: Interesting to see you are using the Magnum K2's - My father had a pair of the MK1's back around 1970 maybe, they were built of plywood I remember & the back was held on by a myriad of screws - I thought they sounded amazing - How do the K2's compare to modern offering as I see them going on Ebay from time to time, he originally ran them with the Goodmans Amp & Tuner (audio-suite?) they brought out - The amp was was only 15 WPC & I think was the first silicone transistor amp, but the Magnums must be efficient as they went quite (very) loud.