The 8b was about 12 watts on the triode setting, more like 30 or 35 on pentode. I have forgotten the sensitivity of the 19s but the 8b should be fine, that was the power rating of many of the best amps of that era. My first stereo amp was a Dynaco Stereo 70, which was 35 a channel, I never had trouble running out of power and I drove less efficient speakers than Altec with it.