buying (NOS) tubes online

Buy from reputable sellers vintage tube  dot net,

vintage tube services , Brant Jesse audio, viva tubes , and a few others 

Also check out Vivatubes for older production Soviet replacements.

For the 6N1P's older (1970's) Vokshod versions should be warmer sounding than later Vokshod and Reflektor versions.

Getting into 6922 types to sub for 6N1P will up the cost substantially.

Not aware of any subs for the 6N6P.

DeKay

@inna i see you deleted your post about not liking Brent Jesse. Why? 
 

my vote is for Brent and Andy for NOS. I try to never buy off eBay because anyone can put down test results and even show a picture of the tube tester that is biased wrong to produce good results. If Andy sold via online in a quick fashion that would be great but because of the slow wait I always go to Brent Jesse. Much quicker. 

+ whatever for Brent Jessee - good tubes, fair prices and easy to deal with. He's my main go to.

Have also purchased NOS Russian 7189A's from Viva Tubes

Also, reliable, though their prices have risen the last few years is Tube Depot

Here’s a complete set for the Valhalla for less than $60- 

https://www.audiozomba.com/product/schitt-valhalla-2/