What tubes would you suggest for the following....

I have a pair of VAC Standard 220's with KT-88's. The tubes are marked VAC on them, but I have no idea what kind they are.

While I like the power and authority that they provide, I would appreciate any suggestions on alternate tubes to try to warm up the sound and move the sound more toward this side of "tubey". The amps now sound great, but lean more towards a solid state amp.

In short, I am trying to get some of the romance and magic that tubes can provide. My speakers are Genesis 501's.

I have read that ELECTRO-HARMONIX KT 88's are terrific, but was wondering if anyone has any other insights. It has also been suggested that I try the VALVE ART ones offered by ATSI (Advanced Tube Services).

thanks. Gerry
Of the current production KT-88 tubes available on the market I would rank them in the following order based on my equipment and my ears:

Other Russian
Anything Chinese

Let your ears be the real judge.
I have had better results changing the 12AU7 input tubes. Try a set of 12AU7 J/J or Mullards and RCA tubes to have a more musical amp. My favorite was the RCA.
I kept the power tubes the same due to clearity of the sound that your Chinese tubes have. Russian tubes in my VAC amp sound dark not musical. The J/J tubes have a very good write up and were used by VAC for a period of time but were dropped by them due to early burnouts and stability problems.
Check out New Sensor they are making a reissue of the Tung-Sol 6550 and also carry EH and JJs. Good place to start rolling tubes and with good prices.

New Sensor

Happy Listening
KT88 tubes branded VAC have been Teslovak (Tesla). This tube is now JJ KT88.

And, I agree, the sound is terrific. I think they are the best of the current KT88 tubes. Others like Svetlana or EH, I guess it depends on your preferences.
Hello Gerryn. Yes, the factory tubes in your amplifier are earlier manufactured Teslas. They are probably better sounding than current crop out there. Jabs earlier post is very astute and bang on here. The 12au7 driver in your amplifiers will have a large influence on the sound of the amplifier. If your teslas are still fresh and test strong [ at least 90% or better] I would experiment with the input tubes first. The topology of my Vac pa90c monos are similiar and respond to these tubes in big way. The factory tubes supplied by vac were of chineese origin [golden dragons in mine]They are not great tubes and rolling them out can have a dramatic impact. The old 50's rca black plate version 12au7 will definately warm things up, but it is perhaps a little rolled off on the top. The common 50's nos RCA 5751 triple getter version is very good choice here. Some food for thought?
Thanks for the recommendations all. I appreciate it.

Does anyone know which of the 4 smaller 12au 7 tubes in the front row on the Standard 220 are INPUT and which ones are DRIVER tubes?

The VAC manual for the Standard 220 doesn't tell you which are which. (?)
I love the Valve Art Cryo's KT88s from Tubeman.com. They were a jump up from Svetlanas.