A McIntosh solid state power amp with autoformers, in the 200 wpc range might be worth trying. It will give you the DC protection you want. I ran very efficient speakers with 60 wpc tubes for a long time, but when I turned it up it would get to sounding a little stuffed. I think now that the amp was reaching its limits, but as they say, tube amps don't clip as harshly as solid state amps. I don't know why. Anyway, an MC2200 changed that. It was a second generation autoformer McIntosh amp. Later ones are no doubt better, and certainly more expensive.