Where can I find affordable tubes for tinkering and interesting sleeper types for DIY projects?

For tinkering, experimenting and unusual DIY projects, the less obvious tubes are often especially interesting. Affordable sleeper types include, for example, EL12N, EL861 / E81L, EF860 / EF80, EF183, E180F, 5678 and 1J24. Many of them originally come from RF, industrial or special applications and are now excellently suited for creative preamps, small power amplifiers, headphone amplifiers or laboratory and hobby setups. The EL12N, for example, also appears in DIY audio projects as a power tube, EF80 / EF860 and EF183 are popular as versatile pentodes, E180F is considered a particularly interesting quality type, and 5678 as well as 1J24 are interesting candidates for compact or unusual circuits. Many of these tubes are available from us at particularly attractive prices.