Power transformer is Hot!

[Profklamen]

I just bought a Vibro-King that sounds great and seems healthy. Using my Weber Bias meter, the tubes read 25ma and 30ma - not exactly balanced, but within a reasonable range.

I've noticed that after being on for 2-3 hours the power transformer seems quite hot - I cannot hold my hand on it for more than a second. It seems as hot as the tubes. It also seems to heat up even when the amp is on standby.

Is this a problem? What could be wrong?

By the way, these amps have massive power transformers.

Thanks

[KLB]

This is typical for a Fender because the heat from the tubes and transformers gets trapped by the upside down chassis and relatively enclosed back space.

[Profklamen]

KLB,

That makes sense, but it seems to get quite a bit hotter than my Super Reverb or Twin Reverb. Could something be wrong that might cause this? or maybe it's just the way Vibro-Kings are designed.

[KLB]

Super and Twin Reverbs have large power transformers, hence their big tone and high headroom. This also means the current draw relative to core size on the PT is not as much.

Apparently, the Vibro-King has a smaller PT than a Super Reverb.
I recall playing one a few years ago and found it broke up fairly quickly. This would tend make the PT work harder.

Still, if in doubt, take it to a tech and have it checked out.
The tubes could be biased too hot, for example.

- Ken