Opera Audio uses Valve Art nickel plate 300B made in China as stock in their 300B amplifiers, due to its good price/performance ratio. However there are customers who want better 300Bs but find their choice is kind of limited inside China. I can check with them if they would like to try out the Svetlana 300B. FYI, Opera Audio is the single biggest customer of Sovtek in China but it seems to me Svetlana has a good reputation on 300B in particular. May be I should email Alex. On the other hand, we can supply VV300B with curve trace matching results too. My good friend bcherry has a nice outlet www.diyhifisupply.com

Cheers,
Stanley