This thread is about a power transformer for a sold-state phono (remember them?) preamp, not an audio transformer in an antique tubes circuit.
The preamp amplifies AC, not DC so the filter capacitor should have a value high enough to produce a low impedance at the lowest frequency of a vinyl record (20Hz).

 

I listened to it again, and I'm not too bad at understanding American accents, I'm sure he said that Jorgen from Norway had a "Project DS2 Tube Box Phono Preamplifier", so I guessed it was valve-based!

 

Powered by a wall-wort. I suppose they exist, but I have never seen a wall-wort that outputs the voltages needed for a tube circuit. This strikes me as a story similar to how you can greatly reduce your car's braking distance by using an oxygen free muffler bearing.

 

Here it is, and it's a nice looking box!
https://www.project-audio.com/en/product/tube-box-ds2/
and it's powered by 18V DC @ 1A.

I had a thread a month or so ago about the best way to generate 200V DC for a valve circuit from 18V DC, and we all thought I should use a simple flyback circuit. I haven't built it yet!

 

It never ceases to amaze me when I see people pay
seriously stupid amounts of Money for a piece of admittedly beautiful Art-Work,
and then justify the Cash outlay by claiming that it provides a practical function that
cannot be matched by anything else on the Planet.

Oh well,
Art keeps life from becoming too boring,
I should be more appreciative.
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