CCa Siemens, gold pins, one of the best sounding ECC88 / 6DJ8 / E88CC / 6922 together
with Telefunken diamond mark and Philips and Amperex, possible close matching. I have three different types, even “all grey”, the earliest type.
This is type II “gray shield” Siemens CCa from 60s.
Matched pair of Siemens CCa gold pins ECC88 / 6DJ8 type II
Type III “silver shield” matched pair from 70s