I'd find out from Fritz the minimum impedance specification. If it's within two or three dB of 8 ohms, then you might get away with a push-pull tube amp, but I would buy as much power as you can afford. Closer to 100 watts the better.
The problem you run into with an uneven impedance curve and tube amps is unbalanced volume between bass and treble frequencies because more decibel watts (dBw) are put into the highs and mids than are put into the bass, which results in the common complaint of the sound being "too bright".
If the speakers have a relatively flat impedance curve, then this is not an issue.
The problem you run into with an uneven impedance curve and tube amps is unbalanced volume between bass and treble frequencies because more decibel watts (dBw) are put into the highs and mids than are put into the bass, which results in the common complaint of the sound being "too bright".
If the speakers have a relatively flat impedance curve, then this is not an issue.