Jolida 1000RC Tube ???

I just received my fresh batch of new tubes from Cryoset (KT77) for my Jolida 1000RC. I replaced all of my older tubes even though they are still in good excellent working condition, anyway, all the tubes were replaced, the system was re biased, etc when I went to turn on the system tube number 8 sounded like loud POP. This was strange since I have never experience a weird noise like that. I turned off the system immediately re check the tube and re-started the amp. Everything seems to be working fine now but now I am concern about this tube that sounded like a lOUD POP, wondering if the tube came in slightly damaged or something else went wrong.

Any ideas?
You might have had a poor contact on a critical contact on the tube pins and the socket, but your description is also consistent with a shorted tube also. Check the bias on that tube. If it is still showing proper bias then every thing is probably well. If not you may have a damaged resistor in the bias circuit. FWIW the KT77's were discussed at some length on AA tubes forum. It seems that there have been a lot of them with undersized pins - you might do a little research on this forum for the background on this problem.
As newbee mentioned, you are probably safe at this point as long as you are able to measure a bias within the indicated range (40mV +/- 5). If there was a problem within the amp, you would not be "working fine now". If you took out a cathode resistor or bias resistor, you would either have one tube with no bias reading or you would blow a fuse within 30 seconds of powering up the amp.

My guess is there may have been an arc due to the potential undersized pins of the JJ KT77 tubes. It has been a common problem. I would recommend you get yourself a small plastic "pick" and go through all your tube sockets and pinching the metal contacts. This will help in making a better contact with the tube pins.