Are Fender and Marshall Transformers interchangeable?

[joesatch]

Let's say i wanted to replace a JTM45 Power Transformer but have come across a Fender PT rated somewhat similarly but very cheap in price. Would this work? Same with the OT ?

[sluckey]

yes yes

[pdf64]

Fender PTs often seem to have their ratings expressed in a different way to Marshall. So make sure to compare like with like. eg the typical Marshall 700V@150mA is probably a ‘point on the curve’, rather than the max load.

[Willabe]

So make sure to compare like with like. eg the typical Marshall 700V@150mA is probably a ‘point on the curve’, rather than the max load.

Would you define 700V@150mA is probably a ‘point on the curve’?

I don't think it is understood by many here including me. 

[pdf64]

I meant that 150mA probably isn’t the max rated current. So 700V@150mA means that when loaded at 150mA, the voltage will be 700V. At lower loads, the voltage will be higher, at higher loading, it will be lower. A typical 2xEL34 with a 3k5ish primary OT and a HT voltage of about 420V at max unclipped output will probably draw more than 150mA.

[dwinstonwood]

A typical 2xEL34 with a 3k5ish primary OT and a HT voltage of about 420V at max unclipped output will probably draw more than 150mA.

As much as I've read on OPT's this is still a point of confusion for me. Is there an "explanation for dummies" for how and why OPT primary impedance affects power tube current draw? If I used a 6,600 OPT with two 6V6GT's would the current draw be more of less if I used an 8,400 OPT?
Thanks!

[PRR]

> If I used a 6,600 OPT with two 6V6GT's would the current draw be more of less if I used an 8,400 OPT?

Dummy thought experiment:
 
300V across 6600Ω is 0.045A
300V across 8400Ω is 0.036A

Those are not final answers. There's two sides to the Push-Pull winding, and we assume sine-waves not steady DC. But the trend is right.