For a more professional sound you can replace the cheap tubes that often come in consumer level audio gear (such as mic preamps) with some NOS tubes.
What is NOS? It means "New Old Stock." Basically the idea being that the new tubes being made today are crap, so you're better off buying a refurbished older tube.
When shopping for tubes make sure you get the right kind that fits well with your gear. 12AX7 is the most common type of tube used in audio gear.
Buy NOS Tubes Online
 |
 VINTAGE 6C4 VACUUM TUBES 1 NOS 1 NOT TESTED  US $1.25
|
 VINTAGE NOS 2D21 VACUUM TUBES TESTED US $1.25
|
 VINTAGE 3 NOS 5726 VACUUM TUBES TESTED US $1.25
|
 BULK PACK OF MISC NOS VACUUM TUBES US $4.99
|
 PAIR of NOS EL34 JJ ELECTRONIC AMPLIFIER VACUUM TUBES US $19.38
|
 TWO MINT NOS RCA RADIOTRON VACUUM RADIO TUBES CRC 112 A GLOBE UX 112 A US $45.00
|