I got an email from a Laney tech, and he says the PT has been used for 15 years and is supposed to run hot 60-70 degrees.. and it is spec. to 12 degrees.
The tech guy suspected the two small yellow thermo-switches (F2 and F3) in the low voltage supply line (feeds bias, reverb and effect loop) to be bad. There has been much writting on the large yellow thermo switch (F1) in the filament supply line to be bad (bad batch from the supplier). And people have either changed it or bypassed it.
I have bypassed all three thermo-switches and left the amp on when biased at 19mA and 22 mA with two jj EL84 tubes and it takes a bit longer for the power transformer to heat up, and though hot to the touch it was slightly "cooler" than before..
I left the amp on for three hours and the idle dissipation was rock solid within 0.5mA of drift. So removing the yellow "bastards" seem to have worked..
Last thing to note is that a standard EL84 should according to the vintage mullard datasheet pull 760mA of filament current but BillM meassured a 830mA draw on the jj EL84 so they might eat a bit more current than the supplied rubys, that also behaved very different in terms of idle dissipation at a given bias voltage. (20mA at idle, JJ EL84 ~ -8.6V, 20 mA at idle stock tubes ~ 12V).