Dynaco ST-70 and 6ohm speakers


High, I have a restored st-70 and a pair of Viena Acoustics Bach speakers that are labeled 6 ohms, should I use the 8 ohm or 4 ohm taps on the dynaco?
Thanks for your help,
Guycom
guycom
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The ST-70 was working with the Maggies for me(at the time) because I was using it only above 200Hz. Well- That was with a 6db/oct slope, through a Dahlquist DQLP-1. Solid State on the bottom. I used(and modded) the combo with a variety of speakers for about 16 years.