(http://www.p4c.philips.com/files/m/mcd908_37/mcd908_37_dfu_aen.pdf) There's the manual. (http://reviews.cnet.co.uk/digitalmusic/0,39029994,49295334,00.htm) there's a review. I suppose when they say, "built in" tubes, that's what they mean. No indication that they are removable anywhere in the manual (or what they might be). I suppose imitation is the sincerest form of flattery. I hope this doesn't ruin anyone to the use of tubed equipment(bad first impressions seldom fade easily).
