i have 4 old vacum tubes from an old table end table style record player. 2 are siemans the other i'm unsure of the others brand. one of the siemans tubes is black on part of the inside is this one bad? is there any reson i should hold onto these? can i do anything with them i cant do with a transistor, traic, draic. they all have 9 pins what are all of these pins do? the small one apeares to be a SAG ECC83S preamp. both siemans apear to be stareo tubes. the blackened siemans has part #ez81, then a siemens EL84, then a what looks like sonotone EL84-0bq6. apears to be a power output pentode (what is a pentode?) i'm thinking about just sticking them in a project case and putting a smalll LED under each of them then conecting all the leds in it to a usb cable for power.