I was hesitant too in buying the 75W equipment due to the vastly conflicting postings on this forum as well as others but then I corresponded with Klipsch as well as Frank Gow (Gordon Gow's son) and went ahead and bought it based on their input. The following is the text of the email from Klipsch :
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Hi Jack,
The RF-7 should be fine with that amp. The RF-7 "likes" a 200 watt amp, but only if it is a Solid State amp, tubes don;t have the same characteristics as SS amps.
You shouldn't have a problem with clipping, when a tube amp distorts at high output levels, basically it just sounds different. It won't harm the speaker.
When an SS amp distorts, it could damage the tweeter.
I would suggest experimenting with the different ohm taps on the amp.
Some suggest a difference in sound, when setting to lower ohms with tube amps.
Try them all, 8, 4 and 2 if you would like, but the speakers should be fine set to 8 or 4 ohms
I have listened to the RF-7's powered by a tube amp from one of our Italian distributors and they sounded great. I do not have any specs on the tube amp we had, I would suggest it was less than 20 watts per channel.
My Klipschorns are tube powered, 25 watt per channel Ultra Linear push pull configuration. I have not been able to suggest any difference in sound using the 4 ohm setting compared to the 8 ohm setting.
The following is a link to an integrated amp Klipsch has in one our rooms. We have driven various speakers with it.
At CES we drove our La Scala II's with it and was able to drive very high levels with it. Maybe I should say LOUD!!
It was set to 22 watts output.
http://store.acousticsounds.com/browse_detail.cfm?Title_ID=16539§ion=music
Read the partial review about that amp, which was done by Stereophile magazine. I am not suggesting to buy this piece, please don't misunderstand my suggestion for the link. It just suggests what we have used recently and were very happy with the lower wattage output.
Bottom line, you should be fine and personally I would suggest they would sound very nice with that Mac amp.
Steve Phillips Home / Professional Audio Tech Support Klipsch Audio Technologies
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Jack