Each tube manufacturers of the 6922, 6DJ8 or E88CC/ECC88 have different sonics (larger soundstage, low noise, warm sound,details, tighter bass.) You will have to determine what areas in your system you are trying to improve on.
The http://www.tubestore.com seems to have a larger stock of 6922 tubes.
Expect to pay $37 to $399 plus for a matched pair. Here are several tubes that I listed if my system required the 6922. Again you have to determine what sonics you want to improve.
Telsa ECC88/ 6922 Gold Pin (used in EAR Amps)
Ei Elite 6DJ8 / 6922
JAN Phillips 6922 (Used Audio Illusion)
Black Sabel Mullard ECC88/6922
For added clarity might as well change the fuses (HiFi Tunning or Isoclean) in the A3000 while your looking under the hood.
The http://www.tubestore.com seems to have a larger stock of 6922 tubes.
Expect to pay $37 to $399 plus for a matched pair. Here are several tubes that I listed if my system required the 6922. Again you have to determine what sonics you want to improve.
Telsa ECC88/ 6922 Gold Pin (used in EAR Amps)
Ei Elite 6DJ8 / 6922
JAN Phillips 6922 (Used Audio Illusion)
Black Sabel Mullard ECC88/6922
For added clarity might as well change the fuses (HiFi Tunning or Isoclean) in the A3000 while your looking under the hood.