Prema luna Prolog 5 replacement power tubes (KT88)


Hi folks. long time no talk. 

The symptom: 
My brother in law owns a Prema Luna Prolog 5 power amp. I suspect that one of his tubes has a vacuum leak. The tube will fill up with a blue flame, then burn off the escaped gas then send a loud pop through the speakers when the escaped gas is burned off. 

The question:
Im looking for a replacement output tube for this piece. I doubt Prema Luna makes their own tubes eventhough the tubes are branded with their logo. I suspect that the tubes are made in China. Does anyone know who manufactures the tubes for Prema Luna, or does anyone have a recommendation on replacement KT88's that sound as good or better than the OEM tubes? Oh and of course he is not looking to go to deep into his pockets. I was considering a set of Gold Lions or Mallards which are in the $200-$250 price point for a set of 4 matched. 

Thanks in advance

-Keith
barnettk
@hgeifman 

Oh Ok I just looked at the link. He has the actual OEM KT88's at $55/per. not bad, and that is in his price range. So there ya go. Thanks this has been very helpful. 
primaluna tubes are rebranded shuguang chinese tubes

upscale kevin deal is also primaluna so he would be the logical source

primaluna amps run relatively modest bias currents in power tubes so they are not super picky with tubes used... you can buy matched sets of chinese or russian tubes of various types from a variety of vendors - am sure you know that these amps have a variety of features that allow much flexibility in tube usage