Which tube choice makes sense for Cayin if you want to improve it or equip it with replacement tubes?

With Cayin, the range extends from classic KT88 / 6550 push-pull concepts to large 805 and 300B single-ended amps. According to the manufacturer, the CS-88A uses KT88 / 6550EH as well as 6SL7 and 6SN7 in the preamp stages, while the CS-805A combines 805A with original Western Electric WE300B as an upgrade and Linlai 6SN7 as an upgrade. This means that the right choice does not only depend on the brand, but very strongly on the specific model and its circuit. Many suitable Cayin tubes are available from BTB selected, as matched pairs or, for power tubes, as premium-matched quartets and pairs.