@bunkertoy , I've owned a SLP-05 for (I think) going on 3 years now. I have no experience with the VTL pre that you referred to. Also, I do not have the golden ear, and it is possible that I may not even have ears that are very good.
With that typed, the Cary does have two pair of balanced ins and one pair of balanced outs. (It also has one pair of RCA outs and three pairs of RCA ins.)
Two of the eight 6SN7s are left and right balanced input buffer, and my understanding is that if you are using the RCA ins you wouldn't even need them installed. I have never used the RCA ins on mine. There is another pair of 6SN7s that are left & right channel headphone amp; I have never used headphones. The separate power supply for the SLP-05 does use one 5AR4 rectifier tube.
As far as sounding tubey:
I don't have a lot of experience to compare with. I have only had two other preamps prior to this one. One was a B&K digital HT pre, and the other was a SLP-90 that I picked up in '99 second hand and had Cary do some mods on, including removing the phonostage and adding a truly balanced circuit (meaning not BINO) from in to out. With the balanced circuit, the SLP90 used three 12au7s for each channel and one pair of rectifier tubes.
Aural memory can be flawed (at least mine can be) but to compare the SLP-90 to the SLP-05, the SLP-90 was a sweeter and warmer sounding presentation. In my own description, I do not find the SLP-05 to be what I would refer to as either sweet or warm sounding with most of my source material. (At least not when I am sober.) What did strike me when I first put the SLP-05 into my system was that the presentaion was larger with clearer and cleaner detail. I would define that detail as better imaging and hence a more palpable or tangible soundstage, but others might not define a soundstage by that definition.
As far as tube rolling:
I have played around with some different 5AR4s (it came with a Sovtek) in the power supply and for most of the time I have owned it I have been running it with a British Amperex which I understand was a tube manufactured by Mullard and branded Amperex. I cannot say that rolling the 5AR4s made a difference that I noted immediatey, but my ears often do not work that way. What I have done that made an immediate noticeable difference was to roll pairs of older/vintage 6SN7s in the left and right balanced input buffer sockets. However, if tubey is defined by warm and sweet, I would not say that this is what I achieved by rolling that pair of tubes. What I believe was accomplished with different tubes in those sockets was a larger (wider & deeper) soundstage with more air and more detail interspersed in that soundstage. In other words, I believe that rolling the older tubes in those sockets enhanced what I felt the SLP-05 already did better than my previous preamp.
That preamp arrived to me with EH 6sn7s in all eight sockets. After I had owned it for around a year I started rolling the the balanced input buffers that I alluded to, but I continued to leave the EHs in the positive and negative phase gain sockets. About ten days or so ago, I replaced those eight EHs with JJs.
As far as rolling balanced input buffers: I have used RCA black glass VT231s, Rayethon VT 231s, and most recently I was using a pair of Ken-Rad (branded Tung Sol) SN7s that someone very generously bestowed upon me. When compared to the first two pairs that I listed, I felt the Ken-Rads lacked some of the detail and air, however I felt their presentation was a bit more laid back and therefore perhaps a bit warmer and (dare I say) sweeter--but not to the point that I would describe it as a "sweet warm sound."
With all that typed, I recently came by a pair of '52 Sylvanias that another very generous individual gifted me with, and earlier today I finished up my second seesion with them. My initial impression was spacious. I would also say that they had more of what I would call a "velvety" quality to them, but that may mean different things to different listeners.
It is worth pointing out that all of my experience with the SLP-05 in my system has been with my system moved into a small untreated room for near field listening and the accoustics which are ubdoubetly flawed in this room may be affecting my perceptions; however, I would also point out, that prior to putting the SLP-05 in the system, I was listening to the SLP-90 in this same room, so the comparison that I am making of my perceptions of these two preamps is not based upon the room.