Well, here is no advice for a tube design, but did you ever listen to a Pass aleph series ?
They are something special and sound very good from scratch, and they are not sensitive to Preamps.
Another interesting idea could be the F1 amplifier ( the First Watt ), these are made for speaker design like you have.
They are something special and sound very good from scratch, and they are not sensitive to Preamps.
Another interesting idea could be the F1 amplifier ( the First Watt ), these are made for speaker design like you have.