Amperex PQ 6922 vs Amperex PQ 7308

Thanks, Ed. That was my thinking, too. Therefore, I am assuming when Joe's Tube Lore is talking about Amperex 7308 with shield, he is discussing PQ tubes whether or not he specifically mentions PQ.

Ed, if 7308 are selected 6922, then what was does the PQ designation on 6922 tubes signify?

TVAD,

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

Nhtran, thank you! I've been going nuts trying to figure out the different tubes and colors and labeling.

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.

PQ = premium quality - it could just be a branding thing but then again it could be some extra selection for matched sections, etc. Likely impossible to say - much lore surrounding that sort of thing has been lost to the mists of time, alas.

-Ed