I haven't tried my 52s on a smaller amp, but I get pretty good output from the BS22s with a very small amp and they are 6 Ohm also. 70W would be adequate if you understand when you need to turn it down if the sound begins to distort. That's the only risk, so if your typical listening level does not sound strained, it should be fine with that amount of power. When they get put into their new home, mine will be driven by my Marantz PM7200 which is rated at 95W.