Need some Amp help - a little new to properly powering speakers

Tim,
We have a similar assessment of moskaudio's current audio system. The speakers are pretty decent and will respond to better quality amplifiers. The Yamaha receiver is the relative weak link in this system. Evidence is that  lower level sound quality improved noticeably when the Rotel replaced the Yamaha. I do believe that moskaudio has recognized the necessity for moving toward a amplifier of "higher quality ". There’s more potential with the Polk speakers to be gained.
Charles

DF (Damping Factor) desirable level really depends on the speaker in question. Some speakers definitely require more than others, some speakers require very little DF. Too much DF can be detrimental to sound quality. There’s no such thing as the more DF the better in every circumstance. Increased DF reflects an increase in NFB and there can be undesirable  sonic effects as Atmasphere has  eloquently explained in past posts.
Charles

30 watts was a minimal recommendation to provide moderate/reasonable listening levels. All 30 watt amplifiers aren’t created equally. There is a hierarchy of quality that definitely exists. For example I would be confident that the VAC Renaissance 30/30 amplifier (excellent output transformers and PS) could drive this speaker from its 4 ohm tap and produce beautiful music while doing so. Problem is you won’t find a used one anywhere near 1K dollars. A used Cayin, Line Magnetic or Quicksilver in the 50 watt range push pull class A/B would work pretty well I believe. Interesting thread.
Charles

Hi Al,
 Thanks for the additional specifications,  I was relying on information from the Polk website. "If"  the tube amplifier has good quality transformers and power supply (PS) I feel the same as atmasphere.  This type of tube amplifier using its 4 ohm tap has a very reasonable chance of success. Atmasphere's recommendation for about 20 db of NFB (or thereabouts) makes sense as this would lower output impedance and conversely increase the DF (Damping factor). 

Meeting this criteria and the need for quality transformers/PS is the challenge for the stated budget for such a tube amplifier. 
Charles 

Amojan,
It was atmasphere who made the positive comment regarding tube amplifiers in his post yesterday. Did you not see this? I personally believe that the key issue here is amplifier "quality " be it tube or transistor. People suggesting just get a more powerful amplifier (quantity) and throwing more watts at the speaker aren't  helping moskaudio (OP).

Moskaudio, I don’t have experience with tube amplifiers in that particular price range. I would look into known reputable brands such as Cayin, Quicksilver and Primaluna on the used market. Those 3 come to mind but I’m sure there are other candidates as well.
1 Regarding tube amplifiers qualify output transformers and power supplies are essential for good sound and performance.
2 Push pull topology with minimum 30 to 35 watts and up (assuming good quality) should work well for you. If you have to exceed the budget a "bit" I’d do it to ensure that the quality of the amplifier is good.
Charles

Moskaudio
Atmasphere mentioned tube amplifiers in his reply to you. You Polk is rated at 88 db sensitivity and an 8 ohm load. It would be very informative to listen to your speakers driven by a good quality push pull tube amplifier of suitable power. You may find they have more to offer  than you're currently experiencing with the solid state receivers, 
Charles 

Moskaudio (OP) didn’t say the Rotel played louder. What was  pointed out is that the Rotel played at lower volume levels was "clearer"`(and better bass) sounding than the Yamaha at similar lower volume. This would suggest that the intelligibility was improved with the Rotel driving the same Polk speaker. This indicates the Polk is capable of better low volume performance when a better amplifier was substituted.

The Polk wasn’t the limiting factor, it was the Yamaha and its limitations. Can you improve beyond the Polk speakers? Yes you can, you can also go further in quality than the Rotel amplifier as well. Some people downplay the importance of high quality amplification and this is an error. Speaker quality matters no doubt but the same can be said for quality power amplifiers. [ can recall experiences where merely changing only the power amplifier resulted in substantial sound quality improvement. 
Charles

Apparently it is the Yamaha. The OP just posted above that lower volume sound quality improved significantly when the Rotel replaced the Yamaha component. OP, I would heed the considerable knowledge/wisdom of atmasphere. He’s absolutely right in that high quality amplifiers sound very good in their "first watt" range of power. Providing more power from a lesser quality amplifier (poor first watt performance) won't solve the problem. 
Charles 

Agree with the sentiment of pursuing higher "quality" amplifier (true for all audio products make quality the priority ) rather than higher power.