Amperex PQ 6922 vs Amperex PQ 7308

IMNSHO PQ=shield, it's the graphic that is on the tube. Sorry if I wasnt' clear. I have only had PQ with shield logo, not any that are either/or.

generally 7308s are quieter and better matched. they are selected 6922s, essentially.

the consumer versions pre-date the military versions in general. Age is by color of printing to a degree. white, orange, green for printing colors, oldest to newest. usually they have date codes on them too.

as with most tubes earlier=better.

-Ed

TVAD,

To answer your question, only the PQ version had the shield logo. The other one has the green JAN label.

PQ and Non-PQ are the same tube. I've not heard consistant differences in sound between the two label types.

On the otherhand, in the gear I've owned, Amperex 6922 and 7308 sound quite different from one another. There is also a difference (in sound) between Holland and USA product with the same internal construction.

I've owned/tried approx. 100 various Amperex White label 6922's and 7308's in Audion and Consonance gear.

Same goes for Philips SQ and Non-SQ labels (based on sampling 20+ of their 6922's). They sound alike.