tube magic with digital source?

Thanks @millercarbon. So do I understand correctly that it is simply a waste of tubes if one only listens to digital sources?

No, and no idea how you got that from me. What I said is:

I think it far more likely that at this stage of the game we have not yet figured out the proper relevant measurements. When we do we will find it is solid state and digital that are by far the most distorted. 

In other words tubes are actually less distorted than SS.
And:

the goal of the system and every component in it is to do as little harm as possible. The goal is not to "sound good". It is not to "be magical". It is to do nothing. Components that do the least sound the best. 

So in other words putting them both together what I'm saying is tubes sound better because they distort or alter the original signal the least. 

So therefore, logically, digital will sound better with tubes. The tubes won't be wasted. Good audio never is wasted. Every tiny little thing we can do to preserve the integrity of the signal pays dividends in sound quality. Tubes do this better than solid state. That is what I'm saying. 

Remember, also said no one is buying this. Everyone is so brainwashed into SS being "neutral" and tubes being "colored" it seems Jumbo the flying elephant is easier to believe. Oh well. 

Jenifer Warnes is a great case in point, BTW.

She is. More than you know. Check this out:  

Famous Blue Raincoat is a supposedly all digital recording. It sounds better on vinyl than any digital medium. So there's one data point. Even better, in final mastering they made four different masters. Warnes, Cohen, and two others (I'm forgetting the names) listened to these four different master tapes. Three of them maintained the all-digital signal. The fourth was to analog tape. All four agreed the analog tape sounded better. 

What this shows, every tiny little step matters. Analog (tubes, records) sounds better, period. FBR sounds better on the analog master, and FBR sounds better on vinyl. Continue on down the line, it will sound better with tubes than solid state. Does not matter what lies upstream.  

This same logic applies to everything, by the way. Every single tiny little link in the chain is an opportunity to either maintain or degrade signal integrity. Nothing anywhere ever can make the signal better. All it can do is make it worse. Tubes sound good not because they make the signal sound good, but because they make the signal sound less bad than digital.

Is the "magic" of tube amplification more pronounced when listening to an analog source as opposed to a digital source? 

Yes. It is. But probably not the way you think.

Almost everyone has bought into the story that SS is somehow more neutral and accurate, while tubes are somehow more distorted, but in a way we like. This story is nuts on its face. Because what this is really saying is we survived and evolved by a preference for distortion over reality. Cannot be. Absolutely cannot be.

I think it far more likely that at this stage of the game we have not yet figured out the proper relevant measurements. When we do we will find it is solid state and digital that are by far the most distorted. 

Whatever. Nobody gonna buy that one, it happens to be true and people these days are not in the market for truth. Just thought I would throw it out there.

Anyway, the goal of the system and every component in it is to do as little harm as possible. The goal is not to "sound good". It is not to "be magical". It is to do nothing. Components that do the least sound the best. 

Well think of it. Jennifer Warnes really is in your room singing. What could be better? How would you even begin to try and make it better? You'd have to be mad even to want to try. 

(I say this knowing full well there's like a hundred so-called audiophiles racing to the keyboard trying to be the first to say oh you need to fix your room, etc etc. Mad. Stark raving.)

So, you follow me? The tube amp does not put more magic into the signal when it comes from a record, and less when it comes from CD. It does the same in either case. It is simply that the signal coming from the record is coming in with a lot more of the original Warnes in the room sound. The CD is horribly stifled, and never can recover, since the job of every downstream component is to preserve and not modify.

What I am wondering is, is a high quality tube amp as likely to present as much of that subtle (or not so subtle) holographic magic if the source is digital?

Now you know the answer: No. It can't. Because the holographic magic was sacrificed and lost to digital before it ever got to the amp.