The OTS transformer doesn't have the necessary 5v tap for a tube rectifier. You can add on a 5v transformer and wire it up that way, or alternatively torres engineering makes a few add on kits with transformers and switches sockets, etc

Gregg

Not entirely true. Amps with OD Channels or even cascading gain amps like the OTS can have Tube rectification. Voltage Sag has nothing at all to do with OD, even output section (PI and sometimes output tube) OD like you would get on some of the amps you mentioned. The reason most amp builders opt for diode rectification is for reliability over their tube counterparts, and also because they are looking for less sag and more touch sensitivity and fast response in their amps. An OD channel in an amp, whether it be a dedicated channel or a cascading gain type will draw very little in the way of current as 12AX7 type tubes don't draw much in the way of current, so you can indeed have a tube rectifier, or two, or as many as it takes to provide the current and voltage you need in a modern high gain amp, but again, for economy and reliabilty, most builder opt for diode solutions.

Gregg