Tube types

The Telefunken E88CC has much longer life (10,000 hrs vs 2000 hrs) and sounds fuller and smoother than the ECC88.  I had ARC SP-9 MKII and MKIII.  The E88CC sounded better in the MKIII, the ECC88 better in the MKII.  

"Have you guys found that switching to premium tubes has been a significant improvement?"       Absolutely!     Less painful, when you only need one.

@jea48- I mostly agree with Joe S, as well. I’m guess he didn’t have any late 50’s-early 60’s, grey shield, CCas. They command a premium price, for a reason. There’s much more difference, in the presentation of the upper-crust Siemens tubes, between their years of manufacture, than he mentions. They vary at least as widely as the Amperex iterations, which he seemed to have in abundance. So many variables, in this aspect of Audio!

@jea48 thank you for the link. There's a lot for me to learn...

@dill thanks for the link. Never heard of them... they sound like a bargain if the performance is that good.

@wlutke thanks; I appreciate posting your experiences. 

@rodman99999 good to know that switching just one of the tubes in my pre to a premium would make a big difference. 

I also(as wlutke) owned an ARC SP-9, some decades back.    I ended up with a Siemens E188CC, in it's main gain circuit.   Hadn't tried a CCa yet, back then.    Every tube, tried in that pre(there were a number), made a distinct difference in the system's presentation.  Of course, some more profound, and better/worse, than others    Again: so many variables!