The Telefunkens CCa is too bright on top for my ears -- too much treble energy -- but this finding is altogether system-dependent.
I have found an inexpensive ECC88 that really sings in my system, i.e., one that was made for Siemens in the Tesla Rosnov factory during the Cold War. Often these were labeled 'Made in West Germany' but the factory code indicates the Rosnov plant in Czechoslovakia. I use these in my Jotas, and find them to be quiet, strong, durable and lovelier than Telefunken CCa in my rig. Also, I compared them to the Siemens E188CCs in my collection, but ended up preferring the Rosnov 'Siemens' in my Art Audio gear.
I have found an inexpensive ECC88 that really sings in my system, i.e., one that was made for Siemens in the Tesla Rosnov factory during the Cold War. Often these were labeled 'Made in West Germany' but the factory code indicates the Rosnov plant in Czechoslovakia. I use these in my Jotas, and find them to be quiet, strong, durable and lovelier than Telefunken CCa in my rig. Also, I compared them to the Siemens E188CCs in my collection, but ended up preferring the Rosnov 'Siemens' in my Art Audio gear.