Pls Help: DIY Tube Pre with 54V (for ICE Power 300AS1 amplifier module)

[stecco70]

Hi,
I think the star tube prj mentioned in this forum might work for the following project but I cannot find the schema...

I would like to build an easy and cheap but good-sounding Head/Combo for Guitar or Bass but I need some help.
So I would like to add a Tube Pre to the ICE Power 300AS1 amplifier module.
This module includes already the power supply (it connects directly to 220 or 110 V AC) and has following extra power outs:
+12V DC, max 300mA
-12V DC, max 200mA
+5V DC, max 1A
+54.5V DC, max 5.5A
I would like to make a Tube Pre using these supplies.
Do you think the Tube Star could work? Where can I find the schematics?

Otherwise I had a very good experience with the Fever 6J1 tube preamp. It's power supply is a dual 28V (schema below).
Can I just connect 0V to -28V and +54.5V to +28 (disconnecting the old tube pwr supply removing R5, C4, R9, C8)?
Do I have to change some components?
For the heating I found that 200mA should be enough.
I found Min heater voltage 5.7V so no 5V, correct?.
I could use the +12V with 2 heaters in series (see schema) or is it better to make a separate +12V from the +54.5V supply?