I looked it up. If you Pre uses 6H23 then any of the 6922 family of tubes can be directly substituted. It has been my experience that using one of th NOS/OS choices that Upscale has on offer will sound better than the Sovtek. Others may disagree but you should explain as best you can what sonic charactristics you prefer. If your not quite sure which appears the case I have found that Amperex white label tubes are well liked.
The gold pins are usually present on the 6922 and up. The 7308 has slightly different electronic parameters making it a particularly reliable tube as well as yielding better sound in most cases. Given all that the best choice in the absence of any specific direction would be the 7308 Amperex as long as they are not the cheesy JAN green letter ones. Otherwise if you have the money to play around buy a few different types and audition them. Tubes are resellable if you don't want to start collecting but be careful its a slippery slope when you first hear the magic of a newly tried tube. It can be habit forming.
The gold pins are usually present on the 6922 and up. The 7308 has slightly different electronic parameters making it a particularly reliable tube as well as yielding better sound in most cases. Given all that the best choice in the absence of any specific direction would be the 7308 Amperex as long as they are not the cheesy JAN green letter ones. Otherwise if you have the money to play around buy a few different types and audition them. Tubes are resellable if you don't want to start collecting but be careful its a slippery slope when you first hear the magic of a newly tried tube. It can be habit forming.