I have been using the K8020 preamp for several years now, without any major problems. The only modification I performed was replacing the tubes for high quality versions of the old ones.
One thing I noticed of this preamp: after a power outage (which does not happend often in the place I live), the preamp switches to active when the power is restored.
The result is that the filaments are heating the tubes for no reason at all after the power outage has been restored, which does not do a good job to the tubes lifetime (to be honest, this was the reason why I replaced the tubes, the factory supplied ones where almost “burned up” after coming home from short holiday with a power outage while I was gone…).
Do other users of this nice preamp experience the same problem? Since I have this preamp for some time, I can imagine that a new firmware is available which prevents the preamp from turning on automatically after a power outage.
Your feedback will be appreciated!