Do European/Asian Tube Amps use step-up transformers?

[Flying Guitarist]

Since many parts of the world use 220-240 Vac service, are tube amps sold for those markets even using a step-up winding to get closer to 300 Vac or do they simply rectify the line voltage directly?

Seems they could make simpler and cheaper amps by using a much smaller power transformer just for the heater filaments, although the amps would run at lower power.

 

[Wyatt]

Since many parts of the world use 220-240 Vac service, are tube amps sold for those markets even using a step-up winding to get closer to 300 Vac or do they simply rectify the line voltage directly?

When building amps for different markets, companies use a different power transformer. Power transformers are all just a ratio. You have a different primary voltage, you use a different ratio to get the secondary voltage they want. But more important, PT''s made for the European and other 50hz markets have to be beefier or they'll burn out (even with a step-down transformer).

There are lots of universal power transformer options as well. A modern universal PT usually give 100VAC, 120VAC, 220VAC, and 240VAC options, running 50Hz or 60Hz, depending on how you wire them. See the second page on here...
http://www.classictone.net/40-18078.pdf

Fender used to build amps for domestic markets and for export-only. They would use the lower cost simpler 110-120VAC/60Hz PT's for domestic amps and universal PT's for ewired for the region they were headed for export amps. Occasionally you'll find a universal PT being used in domestic Fenders as well ('70'ss Champs come to mind).

But other companies, mostly those who relied on exports to North Amercia, would wire a universal transformer up to a switch so they could set all amps for domestic and export sales.