Phono preamp tube rolling.

What components are in your system, any tubes? Which cartridge and TT?

OK then. Phono preamp is an extension of cart, arm, table. I'm sure you will be asked this question again.

I understand. I like to tube roll, however, the sonic characteristics of a tube or set of tubes will depend on the circuit being used.
I can't find which tube type the Ares Magnum uses, but there is a constant in selecting tubes for a phonostage; only use low-noise tubes. You often need to request they be noise tested by the dealer, or you state that they're for use in a phono preamp.
 The reason is the high amount of gain used to boost the signal from the cartridge. If using MC, you may need a high amount of gain which will increase any noise in the tubes. If using MM, not as critical.

My experience was good.

For phonostage I mostly used 1950's RCA black plates. Not as warm as Mullard. More transparent with great dynamics. Need to request low-noise.

Mullard Blackburn longplates are very good. I also like the CV4003 boxplates, although the 12AU7 long plate square getter and large O-getter are cleaner sounding with excellent imaging.

I love the Brimar CV4003 boxplates, similar but more  transparent than Mullard with very good highs.

@pindar. I've paired a Kenrad VT231 Black Glass with a Sylvania VT-231 in my amp. Two very different tubes providing dynamic holographic sound.
And a Tung Sol BGRP in my preamp. 

Yes, a holy grail Tung Sol 6SN7GT from the ’40s. Now listed on Ebay from $450 to $900 per pair.

@mulveling 

the Tung Sol BGRP sounded the most unique out of all, and the best to my ears. An extremely juicy, "technicolor" sound (like Koetsu) that was the only tube which seemed to fully deliver on the 6SN7’s purported promise as "king of tone". The Ken-Rad was my next favorite (especially BG variant), with bass 2nd only to the Tung-Sol. The Sylvania VT-231 seemed a little dry to me but was neutral and could be good in combination with Ken-Rad or Tung-Sol. I also liked the brown-base Sylvania 6SN7WGT, probably more than the tall bottle VT-231. I never liked the gray glass RCA VT-231 as much as these other makes, but it’s nonetheless a pretty good sounding tube.

My thoughts exactly, even down to your remarks about the RCA VT-231.
Ken Rad Black Glass paired with a Sylvania VT-231 produces the best attributes of both tubes.

The only tube I've heard to rival the Tung Sol BGRP is the Melz 1578 OTK, Russian military. This is a magical sounding tube. I know these terms get thrown around, but a pair of these in my amp created a you are there experience, so realistic it was scary.

 Unfortunately, the early years were the best and they're all gone. I have some from 1980 and for a short time I was able to enjoy them before they crapped out. Have one pair that works and I'm saving it. 

The OTK stamp meant it went through quality control and met the highest specs.

@mulveling
There are a couple dealers in Russia and Ukraine selling various Russian tubes. A 1578 stamped on the glass with the multiple holes on the supporting rod is the real deal. Many sellers call their tubes Melz 1578, you just have to see the internal structure to know they are not.

@surfmuz , you are so right. I  mentioned on another tube thread that I'm done with Melz. I purchased a pair of 1578 OTK from a dealer in Russia, 30 day returns. I loved them, ordered 2 more pairs. Long story short, 4 tubes had crackling issues, the remaining pair will reside on my shelf. I'll save them for a rainy day.

I found out later on a different forum about the poor QC after 1970s. Mine are 1980 vintage and can be restored by resoldering the connections inside the pins. A few owners who also bought the 1980s have done it successfully.