A 548

[ppppenguin]

Portadyne > dynamometer > railway. Simples

[Mike Watterson]

The Internet?

I do have a nice Portadyne, They seem based on USA models.
https://www.radiomuseum.org/r/portadyne_...model.html

Wife bought it as a present for me, so it's in the living room. When you get to a station, you go slightly past and the cunning shaft is a slow motion fine tuning.

Nothing now during the day. There was a lot more 14 years ago when I restored / repaired it.

Your A548 is a few years later and keeping with the Portadyne use of surplus / old parts. I expect many had an EL33 not an EL3. As is the more common in older USA models of the 6Q7G dual diode & triode. The EZ33 is rare (and only listed on the entire Radiomuseum for that model!). Likely some production used something more common.
https://www.radiomuseum.org/r/portadyne_a458.html

[Paul_RK]

Aside from the A548, my only Portadyne set now is one of their last, still with its tag celebrating their history if a little too boastfully. The 1932 Portadyne Challenger battery transportable was one of the more reluctant needful departures before our move back to my home town.

Paul