4 ohm vs 8 ohm taps

Eldartford, this is where we disagree. If the 'wrong' ohm speaker is attached to the wrong tap, the tubes DO NOT see a different impedence at the primary. The tubes continue to see the primary winding impedence, whose impedence remains constant regardless of what impedence speaker is attached to whatever tap. The power transfer from the transformer to the speaker, however, is affected and also the distortion because of the mismatch of impedence on the secondary windings to the speaker. Due to this mismatch of power, the volume might not be sufficient and the operator then increases the gain at the tubes, perhaps driving them into distortion, but it is not because of the impedence changing on the primary side.
Salut, Bob P.

inpepinnovations@aol.com...You say quite plainly, "The tubes continue to see the primary winding impedence, whose impedence remains constant regardless of what impedence speaker is attached to whatever tap". It is not a question of misunderstanding. You are wrong.

How do you explain the MC phono pickup step up transformer example?

No, Eldartford, the person saying that attaching an 8 ohm speaker to the 4 ohm tap will cause distortion because the tubes will 'see' a different impedence than if the speaker were attached to the 8 ohm tap, is wrong! When in doubt, use the lower tap, the worse that will happen is a loss of ultimate power transfer, but with lower distortion.
Respectfully, Bob P.

inpepinnovations@aol.com...Have a nice day.

I have a similar situation. I have a CJ MV60 with a 4 ohm tap and 8 ohm speakers. I called Conrad Johnson and they advised me that in most cases, the 4 ohm tap sounds better.