8 & 16 ohm taps at the same time

[Marc]

I had a question asked of me today that I didn't have a clear answer for...

"can you use the 8 & 16 ohm taps at the same time without damaging the OT?"

I wondered how the impedance would be reflected with the two loads and wouldn't the 8 ohm tap see more current, assuming that it is a tap and not a separate winding.

Anybody care to help on the theory?

Thanks,
Marc

[Steve Conner]

You can use them both at the same time, provided you connect a 32 ohm load to the 16 tap and a 16 ohm load to the 8 tap.

[tbryanh]

I am thinking that connecting a 32 ohm load to the 16 tap and a 16 ohm load to the 8 tap is correct.

I was wondering what the logic is for concluding this. Please explain.

[R.G.]

I was wondering what the logic is for concluding this. Please explain.

The idea is that the transformer is still functioning acceptably if the transfomer losses are no more than they would be in the one-winding case and the power transferred from the tubes is no more than the one-winding case.

Steve made the guess that if you load each winding to twice resistance, you get half power in each. The power delivered to a load from a transformer is
P = V^2/R
so if R goes to 2R, then power delivered goes to half.