6SN7 driver tubes


I need to replace a few 6SN7 drivers in my amps. They take 3 per side. I've been using Sylvania 6SN7GTB which sound great, but they're pricey to find reliable ones. I've been considering EH or Chinese brown base. Any thoughts on these? Or any other recommendations? I want to keep the cost under $20 per tube.
mingles
I wrote an assay wich went somewhere. The upshot is . IMHO the Sylvanias are my favorites especially the chrome heavy T plates that are directly opposed with 3 rivets.
Brent Jesse of AudioTubes.com can set you up with true NOS tubes for $20 each,or thereabouts anyway. In your price range.
Usually RCA and sometimes later GE niether of which are that great.He may have some OEM Philco or Admiral etc. Sylvania true chrome dome, top getter, T plates,however. They excell in balanced extension and are a great 3D sound staging tubes.
I have heard that the russian tube is a world beater, but only the real deal old stock tubes. I have also heard their noise floor tends to be high. With drivers that usually doesn't matter. The tube you choose though, will alter the sound even in the driver spot.
If you go for the Russian tube be careful who you buy them from. The seller should know what he is doing and know the other choices.
If you send me an email I will give you a long list of what I think the outstanding attributes are,for the various commonly encountered 6SN7s.
Post removed 
Post removed 
Ditto recommendation of Tung Sol 6SN7 reissue. They get pretty close to the good characteristics of NOS Russian 1578.