I have Cary Audio SLP 03. I got very good results with NOS Mullard CV4003 box plate, Amperex Bugleboy 12AU7 Holland and Amperex 12AU7 Holland (no bugleboy logo, later production). Some of these tubes can be very pricey. In your case you need only a pair while SLP 03 uses four. Therein also lies the issue of polarity. SLP-30 output is inverted. So you have to reverse your speaker wires (red speaker wire on black terminal and vice a versa) for maximum sound staging and base response. Hope this helps