Ampeg heritage B-15 build

[emi2345]

Hey there,

I'm currently trying to build an Ampeg B-15 in a 3U rack-mount chassis. I've been using the heritage B-15 in the studio and I absolutely love it, so I'm trying to make something similar. I've built one valve amp before, a stereo EL84 amp similar to a Leak stereo 20.

I'm working from the heritage B-15 schematic but I noticed there was a slight design change after the first production run; the bias switch and standby switch were combined into one 3-position switch (presumably to avoid the momentary 0V bias caused people switching the bias with the standby off?). I've found a switch that I'm thinking of using, a 4PDT one, would it work?

As in the schematic, I could wire two poles of the switch between the power transformer and the rectifier, and the other two poles switching the bias. When the switch is moved to the centre ‘standby’ position, there is no high voltage going to the rectifier but might there be still be some high voltage on the valves for a moment or so? Doesn’t it take a moment for the high voltage to dissipate from the power supply after the power is disconnected? This whilst the 6L6 cathodes are not connected to anything (ground nor cathode bias). But that should be fine right, no current will flow through the valve. The 6L6 cathodes are disconnected from everything at the same time as the AC is pulled from the rectifier.

Here's the kind of switch I have:
http://www.ebay.co.uk/itm/Wobble-Lever- ... Sw9N1Vqi6G

Any advice on this, or anything else about this amp design would be much appreciated!

Edmund, Oxford, UK