ECL82, 6BM8, 6BM8-HiFi, 11BM8, and 8B8 can be used with internal heater voltage adjustment.

[Auction for this amp]
https://buyee.jp/item/jdirectitems/auction/n1200008961
https://auctions.yahoo.co.jp/jp/auction/n1200008961
[Auction agent]
https://baggageforward.co.jp/en/
[YouTube]
https://youtu.be/m1jbgbJ5lUg