Costello: "Hey, I wanna run my stereo but I gotta burned out tube."
Abbott: "You need a njoe tjoeb first."
Costello: "A nose job? Whaddya mean a nose job? My nose is fine."
Abbott: "That's right, a njoe tjoeb. First."
Costello: "The guy on first needs a nose job?
Jokes apart, it is supposed to be a Dutch word, and the 'j's are silent. So Njoe Tjoeb is pronounced as 'No Job'. I think it means new tube.
I have one - without the upsampler board (I don't have this one installed), the sound is very rolled off and very warm. There is loss of detail as well. The player is a Marantz 4000 CDP with the output stage taken out and replaced with a tube output stage.
I have no idea about the quality of the CDP though. There exist many Marantz CDP mods, and this appears to be one of them with tube output stage.