TUBULAR: Vacuum Tubes in Music and Audio
If you keep up with me on Instagram, you probably saw that I swapped some power tubes out of my Vox AC-10 this weekend. I’d been having noise issues with the amp and after a little inspection of its innards, I found the problem – the power tubes were toast.
A quick trip to Sam Ash and $30 later, my amp is gig ready again. The technical aspects of guitar amplification has never been my forte; that’s more the realm of an electrical engineers and electricians. But dealing with the vacuum tube components this weekend captured my curiosity.
Tube technology is obsolete, yet we guitarists lug around the audio equivalent of those old, bulky TV sets from the 80s and 90s – and we’re proud of it! We pay top dollar and then we brag about our sweet Mesa Triple Rectifiers, Fender Twins or Marshall JVM stacks. But why?
How exactly do vacuum tubes work in an amplifier? Why do they sound so much sweeter than solid state amplifiers? What other types of audio gear uses this type of technology?
What’s in a Tube?
It may seem like some sort of voodoo, but what goes on in a vacuum tube is actually pretty easy to conceptualize. The idea is this: You have two pieces of metal (electrodes) inside a vacuum-sealed tube. One piece of metal (the cathode) is heated up so it begins to release electrons. You run a positive voltage through the other piece of metal (the anode – also called a “plate”) and the electrons fly across the gap, creating an electrical current. This is called a diode tube, and it is useful for changing AC current from your wall to DC current that your amplifier can use. This process is called rectification. Yes – these are the types of tubes Mesa-Boogie refers to when they say dual and triple rectifiers.
But this is the neat part. In the early 20th century, an inventor named Lee de Forest added a third electrode to the diode tube system, creating the first triode vacuum tube. This third piece, called the control grid, controls the flow of electrons from cathode to anode by continuously adjusting the voltage running through it. This is the piece that allows for signal amplification – the signal from your pickups controls the voltage running through the control grid.
Tubes vs. Solid State
Vacuum tube technology largely went the way of the Dodo with the invention of the transistor, but not completely. This obsolete technology yields an inimitable sound that tickles all the right spots in our ears. Arguably, solid state technology is reaching sonic parity with our beloved tube tech, but I invite you to get your hands on a Line 6 or Blackstar solid state amp, blast it, and then plug into a Fender or Vox tube combo. The difference is quite clear to me – there’s nothing like the real thing. It’s like the difference between movies shot in the 90’s and the latest Marvel Studios blockbuster – the age-old debate of analog vs. digital.
To me, the biggest benefit to using solid state amplifiers is the cost issue. Purchasing a tube amp is costly. Maintaining a tube amp is also costly, whereas solid state amplifiers don’t really require much maintenance at all. Still, I’d rather pay a little extra. It’s worth it when I feel that delicious tube breakup on a particularly gnarly double-stop.
Where else do you find vacuum tubes in the music world?
The fondness for that tube warmth is not limited to the guitar world. You find vacuum tube technology everywhere in audio – from the studio to the living room. Audiophiles often opt for consumer-level tube amplification in their dedicated listening rooms. Many tip-top microphone preamps utilize vacuum tubes, like Universal Audio’s LA-610 mkII. Or on the economical side, there are offerings from companies like ART Pro or Presonus as well.
The Tribes
If you look at Korg’s infamous Electribe series of groove boxes, you’ll find glowing vacuum tubes proudly displayed on the faces of the EMX-1 and ESX-1. These were released in the early ’00s, and you can hear the tubes working when you push them. Kirk Dambra, a live electronic performer I had the pleasure of playing with several times when I was neck deep in house and techno music, swears by his ‘tribe – and for good reason!
When a Tube is Not a Tube
Perhaps the most interesting instance of a vacuum tube I’ve found is on Ibanez’s Nu-Tube Screamer, which I first got hands on with at the Austin Synth Expo. Ibanez partnered up with Korg and implemented Korg’s patented “Nu-Tube” technology into the 2018 iteration of the celebrated overdrive pedal. What makes Nu-Tube unique is that it is a “tubeless tube.” Essentially, Korg developed a way to put vacuum tube functionality onto a circuit board without the need for a fat glass tube.
How that works is frankly beyond me – black magic, no doubt – but that’s probably a trade secret.
I can tell you one thing, though; it sounds effing amazing. That’s why I have one on my pedal board.
Conclusion
Will tube technology completely disappear someday? It’s hard to tell. Modern digital emulation of these imperfect analog sounds is getting so good (and cheap, cheap, CHEAP) that some may wonder why bother dealing with this dinosaur equipment. And quantum computing is tantalizingly close to becoming a thing – what will that mean when it trickles into the audio world? Who knows. I imagine it will be awesome, but I’ll still have my Fender Deluxe.
Chris Lazaga
AudioMunk
Do you have a preference – solid state or tube? Drop a comment below and let me know!
