Member's recommendations for tube amplification

David I'd judge the choices based purely on sound quality.  The Line Magnetic 508ia for example is an integrated amplifier that by all accounts outperforms many stand alone power amplifiers.  Also I believe that the preamp section can be bypassed if so desired. It seems the 508ia has a good pre section that responds to tube upgrading.  Waltersalas can certainly address this aspect. 

A high quality integrated can be built with better parts and transformers than some power amplifiers,  it all depends. 
Charles 

Thanks for the shout out, Charles. Yes, I think the Line Magnetic 508ia is an incredible amplifier, so much so that it forced me to reconsider my previous bias (no pun intended) for separates. I do indeed believe that the pre section is pretty great, though I may at some point do some experimentation with a good preamp to see if further improvements can be had by adding a quality pre in the chain. That has always been my experience in the past, but as I said, the LM 508 has resulted in a paradigm shift of what an integrated can do.

I do think it is necessary to upgrade the stock tubes to get the absolute most out of the 508, especially the 300B and 6SN7 tubes, though it also sounds good with the stock tubes. Adding some EML 300Bs and a nice pair of Sylvanias or the 6SN7 tube of your choice will yield very noticeable improvements.

To my ears, it is a stunning partner for the Double Impacts. I've had systems that were more than twice, even three times, as expensive, but I have never had better sound than I have now.

@david_ten I would suggest going the straight amp route rather than getting an integrated. No slight to Line Magnetic or any other integrateds mentioned, I just think invariably you may think about upgrading some part of your system again. When you do having a separate amp and preamp gives you more options, also I am guessing you may find yourself wanting a tubed preamp at some point.

"...I just think invariably you may think about upgrading some part of your system again."

Jond has just described the audiophile condition in a nutshell, regardless of what kind of amp you use. :)

Waltersalas,
I’ve expressed on many occasions my unabashed joy with the Coincident Frankenstein. I truly suspect that I’d be just as thrilled with the Line Magnetic 508ia. It is reputed to have high quality output transformers and power supply. 805 tube driven by the 300b? Sounds like a formula for superb sound quality if implemented correctly. My gut feeling is that this is a very top tier amplifier. I will say that the Frankenstein is one of the very best sounding Amplifiers I’ve ever heard. I don’t see how someone could possibly go wrong with either excellent choice.
Charles