Bias for Jolida 502 P Amplifier

Seriously great amp. I keep mine biased at 500mv just because it seems the amp was built around that point...with KT120s (which I've been using daily for almost 2 years and they refuse to burn out) you can supposedly bias higher, but it sounds fine at 500 so there it stays. The Jolida guys told me there's at least 50mv in each direction that is still conservatively within spec (I think the manual says that also), so there's that. I check it every couple of weeks and there is rarely much drift...10 mv maybe here and there, but my house AC is nothing special and all over the map (I do a load of wash and the LEDs on the 502 blink a little) and the amp doesn't seem to care.

The "break in" period of my Jolida was hard to quantify since it was so subtle and sounded great right out of the box. I noticed more from tube rolling, my most recent being the amazing Psvane 12AX7T-II input tubes...highly recommended. I look at the LEDs when I adjust the bias and it seems that if you turn the bias up to the point where an LED is steady and then back it off until it's almost out, this corresponds to 500mv...in my amp anyway. After that, the house current fluctuations are evident and I ignore that, although the LED blinking indicates a sign of life.

Do Gold Lion KT88s sound better than KT120s in a 502? I think they LOOK better for sure, but I've been putting off buying a set.

When I talked to the people at Jolida about the 120s a while back (almost 2 years), they hadn't tried them, but assured me 120s wouldn't melt the amp. That, plus the good reviews, made me try them. I also liked the 6550s that came stock, and a set of Sovtek kt88s I bought (cheap), so I have all those for backup or whimsy. Psvane 120s do look cool, but since I've seen 150s for about 300 bucks (Ebay) and I assume they also won't melt the amp, maybe I'll try those when my 120s finally croak. Maybe we can start a tube exchange club...loan me some 150s...somebody...

Instead of a stock tube cage, I'm thinking of making a small prison fence replica someday...little guard towers with tiny barbed wire around my tubes. Impractical but cute...I might be able to score something from a prison doll house company.

The issue is deciding which prison doll house company to use?