Tube upgrades for Jolida 502B?


I realize this is something that has come up before, though in searching the archives I didn't come away with a clear path forward. My amp is completely stock and came equipped with Sovtek 6550s. Using it to drive Totem Forest speakers. I contacted Jolida. They recommend KT88s. Their reply is a bit unclear but they might be suggesting Electro Harmonix. They also indicate reliability issues with Chinese KT88s. Response Audio (Jolida dealer and modder) recommends Shuguang KT88s (Chinese). The Tube Store recommended JJ Tesla KT88s on the strength of their great imaging and deep bass (more bass being something I was looking for). I was initially leaning towards SED Winged "C" 6550s. Now I am a bit more confused. I'm curious about KT88 vs 6550 sonics and reliability differences. Thanks in advance to any one willing to take the time to share their experience and preferences.
128x128ghosthouse
I decided to go with th following tubes:
Gold Lion KT88s. In the 12AT7 position, the Mullard CV4024. For the 12AX7s, Tungsram ECC83. All matched and designated "platnium." Get them this week. Cant wait to hear them. HOW LONG DO TUBES TAKE TO BREAK IN???
I've bought a majority of my tubes used or already burned in from the seller so it has been plug in, play and enjoy. From reading in other forums about 100 hours will do for your tubes to break-in. Enjoy. You've got quite a batch of tubes there for your Jolida. I have the Mullard CV4024 in my Jolida amp as well. The only tubes I've been swapping are the 12AX7s.
Or the audio grinch who incited incendiary hifi jinks and stole playback of Mannheim steamroller the world over. Hey legacies are hard to come by in this 5 milliseconds of fame world. Happy New Year everyone, at least the solid state folks will just say...wha?
Risking redundancy I offer the following: My Jolida 502p is currently sporting "matched" KT120s, "Preferred" tubestore 7025s (a Chinese version in the 12AX7 family that really sound great), and tubestore sourced NOS JAN Philips 12AT7s that I just installed...the JAN Philips seem to sound a little more refined than the stock EH 12AT7s, and they have the benefit of having more exposed glowing bits and that's always a wonderful thing regardless of sound quality. "We roll because we can", Wolf Garcia 2013.
question about kt120 tubes. i spoke to walter from underwoodwall the other day and asked if i can use 120 tubes in my 502p amp. he said no. i dident ask why but i see other folks here using them. so, whats the story?? is it safe to use kt 120 in this amp. and if yes, do you still bias so the led,s go on??. i understand they use more current or something so wondering if the 502p power supply stiff enough for them. thanks