Where can I find post office tubes, authority tubes and tubes for professional telecommunications technology?

For post office tubes, authority tubes and professional telecommunications, measuring and amplifier technology, suitable types are mainly sought for preservation, restoration and high-quality special applications. These include sought-after classics such as C3c, E180F, E180CC / 18046, EF860 / EF800, EL861 / E81L, C3m, C3g and D3a. Many of these tubes come from the field of post office, telecommunications and studio technology; E180F and E81L are documented as special pentodes, EF800 expressly for professional telecommunications technology, and C3G / C3m / D3a are considered typical German post office tubes with particularly high-quality electrical data. Anyone who needs the right tube for such applications will find many of these types at BTB.