Output Transformer Questions

[billyz]

After all that then factor in that the speaker is Not a static load either. The cabinet also affects the load impedance and it is ever changing.
Hence the nominal impedance of the speaker is all that is given . I would bet that a sealed cab will have a nicer impedance curve than an open back cab. As the tube amp has a low damping factor , it reacts more to the speaker and cabinet than a high damping SS amp.

For some reason I thought the Dynaco st70 had a primary impedance of 4.3K , more fidelity.

[RJ Guitars]

I found this which gives some credibility to my thoughts on matching up impedance's... as well as gives me at least one transformer that might work.

http://taweber.powweb.com/store/wot45sch.jpg