Difference between Siemens CCa & 7308

I'd opine that in most systems a good 6922 or 7308 will suffice. To fully appreciate the nuances of Cca, the other system components must be a very high level.

I use a pair of Cca in what many users would call a reference phono stage. Yes, and as Grant says, the presentation is more refined and the imaging is better but there is a price to pay for this.

I think most users would be totally satisfied with a high quality Amperex 6922 or Siemens 7308.

YMMV

The CCa have a top to bottom clarity that is unrivalled in any 6dj8 tube I have ever heard. The sound is wide open and dimensional with excellent deliniation of individual instruments. Midrange resolution and depth is really quite impressive. Clarity, neutrality, extension and the subjective impression of linearity. Not the last word in instumental texture or color (see the Telefunken) and though not hot or bright there is the feeling of a slight treble tilt. The bass may be ever so slightly dry. The depth, dimension and detail of this tube is really pretty amazing.

The E188cc sounds more like an amperex 7308, vivid, colorful with deeper and more dimensional bass than either the amperex or the CCa. The mids and highs are liquid with not quite the openess and clarity of the CCa but perhaps better clarity than the 7308. Perhaps the E188cc has some of the best qualities of both the CCa and the Amperex 7308.

The Telefunken is warm sounding, subjectively dark and compressed especially compared to the CCa but that impression seems to leave upon further listening (you quickly get used to it) and you start to hear the midrange resolution and textures, especially with female voice, string, anything with a lot of vibrato. Liquid and real sounding. The bass seems to go all the way down, perhaps exceeding any of the above yet is on the softer warmer side of things. It is probably the best tube for intimate works and small jazz ensembles though my wife loves it when her feet vibrate during O Fortuna using this tube.

I'm using Porter Ports into Eichman Power cords into a Cayin 17d and a DK Design Signature with Synergistic Research Reference Cables as interconnects and S.R. Alpha Quads Actives into Von Schweikert VR-4 Jrs.

I'm currently using a quad of White Label USA Amperex 7308 PQs in the 17d and enjoying, for the time, the CCas. Sounds pretty good. I think the ultimate call would be CCas in the CD player with either the E188ccs or the Telefunkens in the amp depending on my mood but that will have to wait. Anyway I still like the Amperex to much to let them go.

I certainly would not kick a 7308 out of bed for lack of a CCa!