Best 6SN7 for the money?

If you have the vk-150, NOT the vk150se, then the front 6sn7's are VERY critical-they are the input tubes. I'd spend the most you can there. So 4 tubes in your case. Then, replace the other 12. Worked wonders in my old vk60. I've since replaced it with a vk75se. Call BAT as well, they'll have some good advice.

Older 6SN7's are generally better. For the prices you mention, you should have no problem getting used Sylvania or RCA 6SN7GT/VT-231 on eBay. If you go with RCA get the grey-glass.

Based on my personal experiences with GT, GTA, GTB, W, WGT, WGTA, VT-231 and 5692 by various brands (Sylvania, Raytheon, RCA, Tung-Sol, Ken-Rad and Amperex) on Counterpoint and Atam-sphere equipment, the RCA 6SN7GT/VT 231 tubes with grey glass internal coating do demonstrate very smooth high and satisfactory bass.

Happy Listening.

For $60 a pair some of the VT231 types would also be my first choice.

The RCA, Sylvania, Raytheon, and Ken Rad (clear glass) can be had in your budget. The RCA are rich sounding; the Sylvania clear and immediate; the Raytheon on the sweet side; and the Ken-Rad good bass drive..

The best VT231 types are the Tung-Sol and Ken-Rad (black glass), but they will run $130 to $200 a pair depending on condition.

I also like the Sylvania 6SN7W. There are three varieties: A short bottle; a tall bottle; and a tall bottle with a metal base. Prices are all over the map; from $60 to $120 a pair; the metal base ones usually the highest..

For a more modern tube, the 1980's vintage JAN Phillips 6SN7WGTA are a nice tube for around $40 - $60 a pair (brand new). They were the stock tube in the original version of the Blue Circle BC21 preamp; and I think were an upgrade tube in some Rogue preamps.

Some others are the Tung-Sol 6SN7WGT that have a similar sound signature to the VT231, just not as clean (they're less expensive as well). Also the early Sylvania 6SN7GT chrome domes...

You might think about calling Andy at Vintage Tube Services. He will send you tubes to try out. As far as all the opinions, Andy and I spoke today about these tubes. His "take" is that the Tung-Sols are good, but somewhat lighweight; the Sylvanias have great high end, and are good for the input tubes,but are "lighter" in terms of "body"[i.e., weightiness of presentation], so he suggests "balancing" the driver tube with RCA's. which are richer. I'm getting a package of a mixture of tubes to try out on my Antique Sound Lab Hurricanes. I bought some RCAs, but wasn't sure they were the most transparent, so I'm returning them within the 30-day return privilege period.

My experience also. The RCAs are richer sounding, with more weight. I found using them mixed with other, quicker & lighter tubes can provide a nice result.