https://www.worthpoint.com/worthopedia/vtl-vacuum-tube-logic-book-david-247799935
It's a lot of audiophile jargon and such but, it has a bunch of tube data and some drawings of some of his circuits afaik.... I'll try to find a snippet but there are some examples scattered out there...
like this person seems to have a copy with a drawing shown in his listing of one of the pres
https://www.stereo.net.au/forums/topic/248051-withdrawn-or-relisted-fs-vtl-the-ultimate-preamplifier/
I found this weird site.....
https://library.foi.hr/knjige/knjiga1.aspx?B=1&C=X01580
....you have to know how to navigate to the text but it does in fact give you text of the book,,, just nothing else...at least I can't figure it out.....
......of course it's not helpful in this topic..this is primary side........but there is mention of 12v heaters....the 260v b+ ... maybe not helpful at all but it's interesting.... sorry for the derail.....
Power Requirements
All equipment is designed to operate on the various AC voltages around the world. The mains transformers in our units have multi-tapped dual primary windings (for series or parallel connection) that use the following color coding:
Power Transformer Color Code
Volts PRIMARY 1 PRIMARY 2
0 BLACK ORANGE
100 BROWN YELLOW
120 RED/WHITE BLUE/WHITE or YELLOW/WHITE
127 RED BLUE
Hence any line voltage from 100 to 254 volts can be configured; some examples: black and orange are joined together as 0 volts, with red/white joined with blue/white as 120 volts to form the standard U.S. mains/power input, putting the two transformer primary windings in parallel. For 240 volt operation, the primaries would be connected in series, with black alone being
0 volts, red/white (120 volts) connected to orange (0 volts of the second primary) with suitable insulation, and blue/white being the 240 volt termination.
From these examples, it can be seen how 100 volt operation (Japan) is connected in parallel, and how 220 volt operation (most of Europe) is achieved with the primaries in series. Of course, we do not classify this oper-ation as a modification provided it is undertaken by a qualified technician or a competent dealer.
However, we stress that the equipment should not be opened for any reason by anyone other than experienced, qualified technical personnel. Tube equipment contains extremely high voltages400 to 600 volts Direct Currentwhich can cause a nasty or even lethal shock long after the unit has been switched off and disconnected from the mains supply. This is due to the
70 General Operation of VTL Equipment