What didn't you like about them?
I haven't used them enough to make any firm comments.Also I have only compared them to the stock Shuguang tubes that came with the amp
Spark inside the rectifier could mean a bad tube.
I had a similar incident with my AMR CD player.One of the 5687 tubes sparked during warm up (when the HT had just come on) and it took out the LH output board
Price is 4200 euros.
Headphone socket can be put where you want it
It appears the 812A's are run conservatively 480v 35ma
Build time is only around 4months