PT Outer Limits

[andrew]

Hello, I have a 150ma--275v Hammond PT, Would I be pushing it too hard to run a quad of EL84-GZ34-and three 12ax7? Thank you.

[Structo]

Do you know what the heater winding is rated at?
That is the determining factor.

4 x EL84 = 3 A

3 x 12ax7 = 1 A

So 4 amps heater current.

[andrew]

Thanks Structo, mine is only 3A. I love that avatar.

[David Root]

Modern Hammond transformers are VERY conservatively rated.

Which model do you have?

Typically they can handle 30% higher than rated on the HV winding, if they are the same on the 6V3 winding you are still probably OK.

[andrew]

I made a mistake on the specs. The 5vt is 3A and the 6.3vt is 5A. It is a Hammond 270FX. Thanks!

[Structo]

I was going to say that usually the 6.3v tap is rated pretty high with 6 amps being typical for many PT's.

[andrew]

Is the 150ma. high enough for the 3-12ax7 and 4-el84? Thanks again.

[David Root]

I would think so.