You need ONE transformer fro making the AC voltage from your wall outlet (be it 100, 115 or 230V) into the voltages used by the amplifier, which means one HV around 230V and one 6,3V for heaters.
Then you need TWO transformers that convert the high impedance, high voltage low current AC signal from the output tubes into a low imp, low voltage and high current signal that can make the loudspeakers sing.
I know nothing about Japanese sources but near you, there's the
www.vt4.com which sells good components for few dollars.
I'd recommend a pair of this transformer
LM-2014U as OP transformers.
An this transformer cuold go for mains power transformer -
LM-048A
Other useful transformers for output are these:
http://www.analogmetric.com/goods.php?id=211
This transformer for mains power would work as well:
http://www.analogmetric.com/goods.php?id=287
All of those available from China.