I have FOUR Gold Lion Re-issue KT88. I used them more than 2 hours each day and so far no problem at all.
Don't jump to the conclusion on the KT66 so fast.
First, where did you get your KT66? From your message, the seller doesn't seem to be a reliable one. I know that some HK sellers get blank tubes from Mainland and print the LOGO on to make them like brand name tubes.
Second, should your amp be fitted with 6L6 or KT66 in the first place? I used to have a 6L6 amp. THEORETICALLY, it could be substituted with KT66. After giving the schematics to some friends, they told me that I need to do some adjustments before I can "safely" replace the 6L6 with KT66.
Third, my KT88 gold logo peeled off after around 100 hours of use. Only the "mark" is left behind. I checked with one or two friends and they said theirs peeled off as well. From the photo, yours seem to be still intact ....
Sorry, no offence. You are an expert DIYer or just a beginner?
I do DIY for just 1.5 years and throughout this year, I made a lot of mistakes because there are so many things that I don't know.
I don't mean to challenge you but did you check everything after finishing your Quad II? Voltage, BIAS, etc.
Friends of mine also used Re-issued KT 66, KT 88. Some even got more than ONE sets running right now. They have been using these tubes for over 1 year. No problem found so far.
