In need high-efficency speakers

Mjcmt, given that you’ve purchased a pre-owned amplifier, I’m wondering if the reason the sound "hardens" when the volume control is turned up past the 12 o’clock position might simply be that some of the tubes might not be in good condition.

In any event, consistent with my earlier comments it seems to me that buying new speakers to compensate for the fact that turning the volume control up high enough to utilize the majority of the amp’s power capability is not possible without significant sonic degradation, while not first determining what the root cause of the problem is, would not be a good approach. And if the root cause of the problem ultimately cannot be determined, I would consider replacing the amp, not the speakers. As I indicated earlier, you are probably not using more than about 6 watts of its specified 40 watt capability.

Good luck. Regards,
-- Al

Take the amp and the speakers to an audio friend’s place (or to a dealer) and test each out with other gear.

Choose a course once you’ve figured out the issue(s).

It's more advisable to do this than have a friend bring the gear to your place, just in case the issue(s) are not related to the speakers or the amp. That way you will have a starting point.

  Don't take this the wrong way.  I think I'm talking to a man ???? The wife tricked you again
 The time will never be right to buy the speakers 
You want if you ask her for advice. Do it my way just buy the things you want.   It's so sad.  Don't let kids see you it messes up their heads 
 

Eric Alexander will take care of you.   If you know what I mean    Sir.    

So buellrider, do you ride a Buell?