Determining amp rating of transformer from Crate GFX-15 transformer

[pdavis68]

I have a Crate GFX-15 that I've disassembled. I want to re-use the transformer from it. I'm going to get a 24V transformer and connect the secondaries to the 12V secondaries so I can step up to 240V and then use this for a tube build (down the road. I've got several concurrent projects at the moment, but I'm just trying to figure out where my parts inventory stands).

But my concern is whether it'll be able to handle the current. The transformer model number is labeled HK57H-124C, if that's of any help (I couldn't find much online, at least nothing in terms of specs. Mainly other people looking for specs).

But I think my clue is the owner's manual, which under technical specifications, lists the various input voltages:

120 VAC, 60Hz, 30VA
100/115VAC, 50/60Hz, 30VA
230VAC, 50/60Hz, 30VA

So, safe to assume a 30VA transformer?

 

[JMFahey]

I was going to suggest a 1A secondary, based both on amp power rating (a 15W RMS amp should "eat around 50% more than that, so some 24/25VA) and the unwritten rule that says that *rated* power consumption is slightly exaggerated to provide for some margin.

So 24/25VA should be a safe rating.

30VA? ... shouldn't even overheat it, even less burn it, but you might find somewhat higher voltage drop under load than expected.

 

[pdavis68]

I don't think I'm going to have to push it too hard. I was going aim for a pretty low power amp. Something in the 3-4W area, I think. Hopefully it won't sag too badly.