Tubes & Digital - Is There A Link?

To what extent has the ongoing resurgence in tube components been fueled by audiophiles attempting to "correct" for some of the deficiencies in digital music reproduction? In the pro audio sector the causal relationship is quite clear. As soon as digital music production became prevalent there was an explosion in tube based products, particularly mics and mic preamps, but also equalizers and compressors. There was even line level devices that did nothing to the signal except run it thru a tube based circuit at unity gain. Engineers were upfront in stating that they were trying to add warmth, texture and depth to the digital signal. For audiophiles I'm not sure the link between tubes and digital is as clear cut, but I'm interested in what others think.
Personally, I think that although the inclusion of certain tube circuitry in the system may possibly soften the digital sound, there is no way that a problem in the source can be improved by the downstream components. If the problem is not corrected at the source, all the other items in the chain can only color it, or lose some signal. Even a perfect playback system is only capable of revealing exactly what is on the source, and nothing more.

That said, I do believe that the tube additions to digital systems has become very popular to try to cover up some of the digital sound artifacts. I don't really think that "covering things up" is the proper way to go about solving the problem though. And a really good tube system won't do any "covering up" anyway. Also alot of "covering up" going on with cables in digital systems. And the quest for "non-fatiguing" speakers to "cover up" the "fatiguing" digital sound. And on, and on. It seems that many audiophiles spend thousands on trying to "cover up" the sound of the source item they picked.

It's funny how you never hear about any vinyl addict posting a question about how he can make his analog rig sound more "digital". :^)
I don't think the focus of tubed recording gear is to "correct" sonic deficiencies of digital but to attempt to deliver a higher quality reproduction. Tubes, inherently, are capable of producing a higher level of detail than solid state. Also, it's argued that tubes produce a more "natural sound" because they generate even-ordered harmonic distortions as do acoustic musical instruments, compared to the odd-ordered distortions produced by solid state. However, tubes are hampered when it comes to high frequency response and bass control. The "warm" sound produced by even-order harmonic distortions is magnified by output transformers (mostly) and, ironically, poor circuit design to some extent.
There is recording gear out there that uses OTL topology in order to take advantage of the tubes inherent qualities - not really to mask the digital sound but to minimize loss of detail in the entire audio recording chain. At least that's my $.02
I have a copy of an article that is about 5-6 pages long that discusses the history of the tube, the current uses of tubes / tube industry, the stopage of the development of the tube and why there is a resurgence in the development of the tube. The article basically states that tube development is becoming mainstream and that it is a micro varient similar to the solid state device that replaced it; but with tube design topology. If anyone is interested, I will see if I still have the article or can get my hands on a copy.

GS5, what pro oriented equipment uses an OTL design?
Pendulum Audio and, I think, Mesa. I'm not in the recording biz - the Pendulum gear is something I read about in a guitar mag a while back.
Tubes seem to add "fullness" rather than warmth. They also add depth and soundstage.

My pet theory is that the second harmonics help activate the location reponse of human hearing. A thin sound, such as a high-pitched beep, is often hard to locate. A harmonically rich sound of the same pitch is much easier to locate.

Why a resurgence of tubes when SS is measurably more accurate? My feeling is that digital/SS is losing something that is not being measured. The measurement standard, harmonic distorion of a single sine wave, is missing something.

I know about Fourier Analysis and the Super-Position Theorem but who said these audio systems are guaranteed linear? We're missing something.

Just my 2 cents.
In my experience, tubes can add depth, amazing layering, bloom, body and some add warmth (all of which good SS can also do), but I also think tubes with a digital source make the sound somehow artificial, synthetic, if you will, and am going back to all SS gear on an all digital front end.

On a side note, I recently heard an all McIntosh setup, with tube amp and preamp, McIntoshch cdp and speakers, that sounded so much like solid mid-fi solid state reproduction I had to make sure the speakers where in fact hooked up to the claimed components. It's just about tradeoffs, you pick your compromises. I have found SS gear to sound more real, more believable, less synthetic, but can see where the appeal of tubes come from with a digital setup, especially with a hot tweeter and limited range speaker, where only certain types of music is listened to.