4 ohm vs 8 ohm taps

Stevecham, use the 4 ohm taps.
Atmasphere, further to my other note, the tubes don't 'see' the impedence on the speakers, but the impedence on the primary of the transformers, which DOES NOT change with the whichever taps one uses on the secondary.
Bob P.

inpepinnovations@aol.com...The primary impedance depends greatly on the secondary loading. If it didn't why would transformers have multiple taps?

Eldartford, you know of course that the secondary on the transformer has different taps, 4, 8 and 16 to match the speakers. Those taps simply have different amount of winding to 'transform' the primary winding impedance which is constant. The tubes themselves don't see the secondary taps or impedance.
Salut, Bob P.

inpepinnovations@aol.com...You have it backwards. The different taps of the transformer secondary make it possible for the tubes to see the same (high) impedance with different loads.

Here is a way for you to test your theory. Short out the speaker terminals of your amp and drive it hard. If your theory is correct, the tubes won't see the short. After the fire department has left, post results of this experiment :-)

Eldartford, exactly - the tubes do not see the difference of what is connected to the secondary taps or to which taps the speaker is connected. The poster that said that connecting the speakers to the 'wrong' tap would make the tubes 'see' a different load and thus distort their output.
The reason that the amp overheats when shorting the speaker taps is due to the tranformer trying to drive a 0 inpedence load and thus drawing more power from the tubes on the primary side. It has nothing to do with the impedence changing on the primary (which doesn't), which the tubes 'see'.
Salut, Bob p.