TUBES 6922 pinched waist

Talon4,Thanks for explaining the sheild.I have only 2 tubes in my pre they are seimens CCa type.They sound great. With only 2 I can play with different tubes.I just tried some Amperex 6dj8 Bugle Boys white lettering.They lacked bass and were harsh in the highs.I hope the PQs are better.

What does the falcon mean on the Seimens, Does it tell you the age or quality of the tube? It looks like the letter H in the middle of an S Does it mean they are Halskes?

Gellis1, I thought I'd add that Andy @ Vintage Tube Services does testing as well. He has a lot of the old testing equiptment-pictures on his web site- dating from 1920-1960. For $6 a tube, he can test your tubes for use-(how close they are to being new), shorts, etc. and tests them in a testing booth for microphonics. I had him test a batch of new 1976 7308 Jan Sylvania tubes that I stumbled upon in my area. He matched the survivors, which was about half of the tubes sent, labeled them and sent them back. Also, if you do buy tubes from him, he backs them up for 1 yr. Good hunting! Stan