7308 tube code question


I just received 10 NOS Amperex 7308 from my father. Each tube has the following markings:

All lettering in white
USN-CEP
A white triangle like symbol
VR5 *5B etched in the glass

The only nomenclature that I am familiar with is the USN = US Navy. What does the rest mean? What do people think of these tubes in a phono section of a pre-amp designed to take 6DJ8's
brf

Showing 2 responses by brf

OK, now I am confused...the tubes say made in the USA, has a *5B etched under the VR5, which I am told means made in the USA, but also has the large white triangle (delta) which denotes made in Holland. Please note that the triangle is quite large and independent of any lettering. Am I confusing this triangle with a triangle used in place of the * to denote origin of manufacture??
These tubes sound awesome. I have a Sonic Frontiers Line 3SE with 10 NOS Valvo 6922. I replaced all 10 Valvos with the Amperex 7308s, and what a difference, especially in the deep bass and a more fleshed out natural midrange. The soundstage is huge with these tubes. I generally experience a subtle change when tube rolling, but this change was dramatic. Some tell me that changing all 10 tubes in my pre-amp with 7308 is overkill (instead of changing just the first two positions), but what the heck, you only live once.

USN-CEP - That is the older Navy code for Amperex Electronic Products. "C" is for Commercial. The remaining letter or letters identify a company:

CG = General Electric
CW = Western Electric
CRC = RCA (Radio Corporation)
CRP = Raytheon (Raytheon Production Corp)
CTL = Tung-Sol

The 65-35 on Dekay's tube is the date code i.e. manufactured on the 35th week of 1965. The delta symbol on my tubes are above the Amperex name and in the same colour ink as the rest of the lettering.