Tube Vs. SS Preamps

i am curious to know what you believe to be the source/reason/technical underpinning behind top level tube gear being able to generally (exceptions exist of course) provide a greater sense of air and vast imaging (size, depth in particular) - compared to similarly high level solid state gear?  

I know what you mean. IMO it has to do with the distortion signature- neither a tube or solid state preamp will be making any significant distortion but its a simple fact that distortion is inescapable.

Its been shown that the lower ordered harmonics serve two functions both of which are helpful. The first is that if they are there at sufficient amplitude, they can mask higher ordered harmonics that otherwise are perceived as brightness.

The 2nd and more important function is that somehow the 2nd and 3rd harmonic are helpful to the ear in some way in helping it to perceive soundstage width and depth. You might be easily convinced that this is some sort of effect rather than being neutral, but if you listen to a direct microphone feed and compare that to the actual musical performance you find that the sound stage is simply being presented in a more natural fashion.

I think more research could be done in this area, but I'm not holding my breath for it to happen. But it is a documented phenomena.

Freya + will give you both. If you want tubes turn the tube buffer on if you don’t want tubes turn them off. I feel tubes are vital when streaming. Some or most digital streaming that is not run through tubes feels like razor blades to my ears, listener fatigue can set in fast. I have rolled tubes to find the sound I like too.

This week I replaced my c-j Classic 2SE with a Zesto Leto preamp and the difference was not subtle.    It was staggering.   Having that component in my system has cemented my belief all along that the preamp is the most important link in the chain.  Speakers ?   Not as much ,  putting the Zesto in place made it seem like I upgraded my speakers ..... incredible sounding piece of gear.   

I always find this TUBE vs SS discussion entertaining.....If not silly. After near 50 years as an audiophile and 40 years in the HiFi business, I've found there is as much musical difference among various SS and tube  amps and preamps as there is between SS products and tube products.......If there wasn't, there would be far fewer manufacturers and no need for reviews, magazines and forums such as this.

Mush more important, is the combination of devices......You can buy all the amps, preamps, DACs, streamers, turntables, cartridges and speakers you want. Buy the most expensive and highly rated products on the market, put them all together and in many, if not most cases, the total system will sound terrible. 

This is the VERY difficult part of Audiophilia......There are hundreds of thousands of combinations....And hitting one that works for you might be like hitting the Lottery.

But THAT'S what makes the hobby so much fun......It's the hunt!

Very true, even though many products measure perfectly they all sound different.  I have three preamps in front of me.   All pretty good , they have their own character and presentation of the. music.   

From personal experience these differences are a little more pronounced with tube gear .  My newest preamp doesn't really sound like anything but I'm getting more of everything if that makes sense....

What ever flavor you like I think the preamp is the most important link in the chain as it can often be the bottleneck of a great system.