Telefunken vs Siemens EL34

I'm have been looking to upgrade my EL34 power tubes in my amps. Does anyone know if there is a sonic difference between these two brands ( in the EL34 version )? I have studied many photos of the 2 brands, and they appear to be identical in consrtuction.

They are definitely different, both in sound and construction. has some pictures. I have a pair of the "round hole in plate/wings" version, NOS factory matched, that are available. IMHO the rarest and best of the breed of German EL34s.

I would ( due to cost ) really consider calling Tube World and ask about trying there Svetlana "cryo'd" EL 34 which they rave about. It'll be much cheaper and probably sound very close to buying used or nos Teles' or Siemens.
What amp? Can you fit a new EH 6CA7? You might like this sound at a much lower price.