Hyperion has recommended a BC337 sub over on the Sansui forum recently. And I see Pete just made a recommendation as well. Looks like the main difference is the BC337 has a lower fT than the original (100MHz vs 300MHz) whereas the PN2222ATA is equal at 300MHz. I don't know if the speed is critical at that position so will defer to Pete's recommendation. Original SC735: http://www.datasheetspdf.com/PDF/2SC735/613419/1 Fairchild PN2222ATA: http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/PN2222ATA/ Either way the replacements have a center base pinout and will need some lead bending to fit. The original was center collector.