Biggest issue with batteries is tube keeping filament lit I would guess.

I just looked at the spec sheet for SE84 and it indicates 65W. The Zkit will be less by what a typical rectifier filament will draw. 5V@3A ~ 15W.

Watts = current*volts

Not so up on EU based suppliers, but Lundhal makes some excellent iron, I use for many projects. Finding these in Sweden could be easier . For the output transformers, you can find something in the 5-6K impedance/8 ohm range.

Let us know how it works out.

Hi all, soon the soldering will start. Went for Hammond transformers.

Have a few questions:

1. Installing meters. On the first build ZKIT1 PCB, before next one that will be PtP with a meter per channel,  I will go the easy way adding just one meter. Have read across the forum: Eg. New build have questions about installing meters

Will the below wiring work out, or should eg. the 1000uF Capacitor be wired differently?
Left, showing 1 meter build just lifting the 150Ω from the PCB and connecting Meter and Resistor in series.
Right, a meter per channel (when doing PtP)

For each option how much mA can I expect? Meaning to go with 50mA Meters as on the SE84UFO2.1 or 100 mA?
(any suggestions welcome on where to get Meters in EU with low impedance. Amazon etc is usually 630Ω, and to much taxes and tolls etc from US)




2. Gain Switch
Thought I add a gain switch, though saw on some older Schematics that a DPDT switch was used "shortening" the 2,7Ks (see Right version below), any reason for that? My idea was to just use a DPST switch like (left side below)?




3. Fuses Secondary side of PT
In docs for the SE84, it is mentioned fuses inside chassis. Found the below pic.
What are the pros/cons of these fuses? Like many things on the internet there are as many opinions as people.




That was the most urgent questions for now
Will post a share-link of my full circuit done in Lucidchart later on.