Adding tube sound to my SS system

@fuzztone that is not accurate unless you are using a Flea-watt Tube amplifier. Many PP Tube Integrated and Amplifiers on the market that will power inefficient speakers. AR, Unison, Jadis,  Rogue, AH, Octave just to name a few. I have speakers with 88 db sensitivity and my Octave V110SE  drives them spectacularly and sounds heavenly. 

@tkrtrb125 think he meant that the BHK preamp uses both tubes and transistors as amplification devices, and that OP should try a preamp that is pure tube. Power amp is not in play, at least according to OP's provided context. 

This is sacrilegious, but I’ve experimented lately with SS lines stages versus my tube line stages. What I’ve concluded is that good SS line stages (Phison PD2 SE, Meridian 808v5) are highly transparent. When I add a good SS line stage in front of a tube line stage, the resulting sound is 99% that of the tube line stage alone.

That said, when I run the SS line stage on it own - directly driving power amp - it’s missing that "breath of life" in the midrange. It sounds "very good" to be sure, but I absolutely CANNOT enjoy music like that, long-term. I’ve tried. My favorite tube line stages also don’t cause any constriction to sound stage; in fact they enhance it. They add engagement factor in spades.

This is definitely anti-purist. However, I find value-add in the conveniences of the SS line stages - particularly the superior remote volume control (pots and stepped attenuators suck here) and the Left / Right balance control. Even slight channel imbalances drive me CRAZY, and many systems have one to some degree.

So am I using these expensive tube stages (VAC Master, Rogue Hera, ARC Reference 6) just as a fancy "coloring box"? Maybe. Do I care? No. I think of my eyeglasses, which from a technical standpoint are horrible little distortion generators: they add geometric distortions, chromatic aberrations, reflections, impose on the fringes of the image with their frames etc. However, they work with my own flawed eyes to allow me to perceive and enjoy much more detail than I could otherwise. I feel the same is happening with tube preamps, on some level - whatever psychoacoustics are going on between our ears and brain, the tube preamp transmits more of the musical message in a way I can enjoy it. "Ultimate transparency" be damned.

@tkrtrb125 oh my bad lol. You are right; I scanned too fast. It's extra confusing because they make both BHK preamp and power amp units, and I think both are hybrids.

https://tmraudio.com/components/preamplifiers/modwright-analog-bridge-tube-buffer/

@jbuhl  Yep - the "Analog Bridge" by ModWright is a fantastic suggestion for OP that shouldn't get buried. And Dan Wright is truly a great guy. I almost picked up one myself, but I'm such a gear hoarder and already have so many tube components - I'm not sure I have a use case for it yet. Seems perfect for OP to try. 

A lot of tube preamps use something like an Alps RK27 pot (aka "Blue Velvet", or its motorized version), which always audibly penalizes sound quality (even if slightly) whenever I've compared it to other alternatives. Even up to very high MSRP's, you see that ubiquitous blue plastic pot all too often. I hate it! I absolutely hate the Alps Blue. I can't understate that. In general, the volume control is often a weak point of the tube preamp. The Bridge avoids that issue.

I was running a Rogue RP-7 tube preamp into a highly-regarded Rogue tube power amp, the power amp replacing a SS amp driving my Fyne Audio F-702 speakers that were made in Scotland.  I felt it resulted in degraded tonal qualities of instruments, reduced definition, and slightly reduced soundstage.  I replaced the tube power amp—but kept the tube preamp—with a pair of Odyssey SS monobloc amps, and I have regained what I lost plus gained better imaging and depth and lateral dispersion of soundstage. 

@mike4597 Most of the Rogue power amps (I had Apollo Darks) do not sound like traditional tubes. And the RP-9 didn't sound even *slightly* like a tube preamp to me (like the RP-7, it's actually a hybrid). I've had Solid State amps that are actually "sweeter" sounding. Glad you found what works in your system! Nice speakers.

Personally, I didn’t find the Yggdrasil to bring me anywhere near to what I expect from "tube sound". It was a very good DAC to be sure, but still rather SS sounding. The Meridian DACs (566, 808 series) are not even R2R and get me closer to the sound I wanted than Yggy did - but DAC rolling in general is no substitute for a tube component downstream, if that’s what one craves IMO. I used Yggy most with tube amps, and liked it better that way than paired to SS amps.

For context - I had the OG Yggy Analog 1 and later the Analog 2. Haven’t heard the recent ones. The USB implementations back then (USB 3 and then USB 5) sounded awful to me (bright, lean, fatiguing) - had to feed it coax to be happy.

OP could look at tube DACs, but they’re simply a DAC box with a tube output buffer built in. Modwright’s bridge will be much higher quality and more flexible.

How is the Yiggy an R2R DAC? It uses a DAC chip. Unless I am missing the meaning of an R2R.

A chip is just a package. It doesn’t disqualify R2R / ladder conversion. The Yggy (OG versions, at least) were an R2R DAC based on a chip that was (IIRC) manufactured for medical devices, and re-purposed by Schiit’s digital engineer. BurrBrown made an R2R chip that was popular for a long time - the 1704.

Now if you restricted your query to discrete R2R, then chips would be disqualified :)