Guitar players are always searching for the perfect sound, kind of like radio.

RASCOE: And when it comes to amplifiers, valve amps rank above all others. Those are the types Peter Frampton used to record the iconic album "Frampton Comes Alive" in 1975, and he still uses them. Valve amps are electric amplifiers that employ vacuum tubes. And bad news for guitar fiends - there's a problem with the valve amp supply chain. Randall Ball is a musician and the owner of Ball Amplification in Kerneysville, W.Va., and he joins us now to explain. Thanks so much for joining us.

RANDALL BALL: Happy to be here. Thanks for having me.

RASCOE: So the kink in the supply chain is with the tubes, right? Like, what's going on with that?

BALL: Well, the majority of tubes are made in Russia. And with everything that's going on over now with Russia and Ukraine, it's definitely caused a problem, you know, for tube amp builders and people who play through tube amplifiers.

RASCOE: So tell us about these little glass tubes, which older people know from radios and televisions. I know about them, too. I'm not that old.

BALL: (Laughter) Well, I do know that the vacuum tubes - they just impart a warmth, for lack of a better word, to a guitar. It's almost like an extension of the guitar. It's almost its own instrument. It adds its own character to the sound.

RASCOE: And so - and I know that you have a friend with you right now who can give us an example. Let's hear a little bit from Oskar Buie.

RASCOE: That sounds good to me (laughter). I can see why people are going all-out to get that sound. That's a nice sound.

BALL: Yeah. And, you know, it also helps to have a good guitar player like Oskar here.

RASCOE: (Laughter) So do these tubes last a long time?

BALL: It all depends. They can last a long time. It really depends on how often the tubes are being used. You know, like, for a working musician who's playing every weekend and all the time, tubes could last maybe a year or two years.

RASCOE: And so right now, if they break down, can you find them?

BALL: You can find some new. It is really difficult. So what I've done with my customers is just had them look for new old stock tubes, NOS. So basically they're tubes from the '50s and '60s that are brand new, just sitting in a box - you know, like just old inventory.

RASCOE: That never got sold.

BALL: Exactly. But you know what? Some people actually like the sound of new old stock tubes. They prefer the vintage ones, anyway, over the ones that are made today.

RASCOE: Yeah. So tell us more about the tone they produce. I know you said that they're warmer. Frampton has said, quote, "it's something I don't think you can actually put into words." So maybe it's unfair to ask you to give it a try. But you said it's a little bit warmer. Tell us a little bit more about, like, the sound that it produces.

BALL: You can emulate it with digital effects and things, but the sound of a tube amplifier - when you're really kind of driving it, it's really loud and you're really working the tubes really hard, they start to distort in a very pleasant way. You know, it's just part of the characteristic of the tube. And, in fact, a lot of old rock 'n' roll records from the '50s - that distortion was unintentional. In fact, they wanted the amplifiers to be clean, but it was just an accident. And then, you know, the rest was history.

RASCOE: All right. Well, that's Randall Ball of Ball Amplification in Kearneysville, W.Va. Thanks so much for joining us today.

BALL: Oh, thank you for having me.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.