I would suggest going to the link below and buy two matched pairs. I have never been disappointed by any tubes sourced from Cryoset. I have tried Psvanes in the not to distant past but they got noisy after a half year or so in circuit.
http://www.cryoset.com/catalog/product_info.php?cPath=21_42&products_id=123&osCsid=0a4o4i7fccbcugftg62g2locn3
http://www.cryoset.com/catalog/product_info.php?cPath=21_42&products_id=123&osCsid=0a4o4i7fccbcugftg62g2locn3