The P1800 was initially designed for EL84 power valves. But there are also some oddball alternatives that can – with a little tweaking – fit into the 9-pin socket instead of the EL84. Stephen Rattley opted for some 6CH6 valves, which need a small adaptor…
“Hot input, together with all other elements of the amp now work fine. It came into operation after reorganising the input jack mini circuit and discovering a whisker from the shielding of the cable from the jack to the turret board connection. I have to say the Hot input does not sound bright to me, just a bit more lusty.
“I have also spoken to Ned the American gent who owns Tubezone and he has several thousand of these, together with the adaptors, so there is a good supply of these tubes. Nice chap.”