Every so often, a piece of gear or an invention comes along that revolutionizes the guitar game. The Spirit Tone Generator – based around Hughes & Kettner’s Spirit technology, found for the first time in the Black Spirit 200 amplifier – is one such item. But what does it do exactly, and why is it such a great thing for the future of guitar tone everywhere? Let us take you back to the beginning to explain…
Solid-state circuits are a polarizing topic among guitarists.
Even their detractors will concede that they’re robust and reliable, but get to talking about the tone they produce and you will find yourself embroiled in debate.
This didn’t deter the many manufacturers who have seen fit to dabble in transistor circuits time and time again since the late 1960s.
Some of these amps were even a commercial success. One was a stylish trendsetter, the legendary Roland JC-120, a stereo solid-state combo with a built-in chorus effect.
Unloved and unlamented
Apart from a few other noteworthy exceptions, though, transistors were the stuff of cheap bread-and-butter amps.
The classic combo for beginners was often one of this breed. Many ended up abandoned in rehearsal rooms, unloved and unlamented leftovers gathering dust in the corner.
People associated tone with tubes, so these continue to feature prominently in most ‘respectable’ guitar amps.
The tube was a proven part, mass-produced for military use, with a familiar technology. And it was the mother of nearly all the trademark sounds of rock ‘n’ roll.
When many of the big brands discovered Asia as an ultra-affordable offshore manufacturing vehicle, tube amp prices plummeted and it seemed this tech would still have a lot of mileage left in it.
Even the emergence of modeling technology nearly 20 years ago was just a road-bump.
Tube tone: still king?
The trusty tube was still the measure of all things tone.
Modelers merely imitated the sound, but they did offer a lot more possibilities and reliability in a lighter package.
That made modeling a serious alternative for working musicians. Touring is big business these days, and truck space is a cost-point that weighs heavily on the bottom line.
Economics is one of the reasons why we’re seeing amps that are more computer than analog sound generators behind guitarists on the world’s big stages.
The next top modeler
A modeler computes sound using smart algorithms. The audience in front of the stage can’t hear the difference.
It sounds as good as it always did.
But it doesn’t sound better – how could it when logic would dictate that a copy can’t sound better than the original?
If you ask the players, though, they would much rather take their old tube-driven treasures out on the road, but the rational thing to do is to leave them at home.
Ah, those were the days, when the rock ‘n’ roll circus was no place for rationality.
In touch with the true nature tone
So, why not have it both ways and reproduce the behavior of a tube circuit from the input jack to the speaker?
We’ve seen attempts to do this by modeling the preamp, EQ section, rectifier and power amplifier. Been there, done that.
How about if we find a way to get in touch with the true nature of tube-driven tone?
At the risk of getting metaphysical, how about if we tap into the spirit of the tube?
What happens between tubes, capacitors and resistors may appear to be random chaos outside the bounds of the laws of physics. That’s not the case, though.
This does follow certain rules, but as they say, it’s complicated.
It’s a long way to the top (if you wanna rock ‘n’ roll)
Figuring out a way to shoehorn the give-and-take between the input section, voicing section, rectifier, output stage, and output transformer into a compact, fully analog circuit was not going to be easy.
It would take a monumental development effort. Now if only we could find a developer with a deep well of over 30 years’ experience building tube amps to drawn on…
Enter Bernd Schneider, tube-gear guru and chief developer at Hughes & Kettner.
This idea had been germinating in his mind for several years. He’s been fiddling with soldering irons for a very long time now and could foresee that tube technology had evolved about as far as it could go.
Is the day of the tube numbered?
Tubes sound fantastic, but compared to ultra-reliable contemporary components, they’re an anachronism, a relic from a distant past.
Tube manufacturers are a dwindling breed; we don’t know how long amp makers will be able to find the right type of musical-sounding tubes for their needs.
Actually, that’s already a challenge today.
The Spirit of tubes
Once the go was given to explore this avenue, Bernd set out on a mission to capture the spirit of a tube circuit in a discrete analog component that would come to be called the Spirit Tone Generator.
It took years to translate all the complex processes and myriad interactions between the various circuits, tubes and output transformer.
Not nature, but second nature
Of course, Mother Nature didn’t create the tube amp. But they’re second nature to those of us who grew up with these amps.
That’s why we’re comfortable comparing the efforts of Bernd and his crew to bionic engineering.
They set out to mimic a system found ‘in nature’.
Everything that happens in the individual stages of a classic tube amp circuit influences neighboring stages.
This interaction is constant, simultaneous, and more chaotic than not.
Bernd and his buddies distilled the essence of all that into the Spirit Tone Generator, which is now at the heart of the Black Spirit 200.
And that’s why this 200-watt monster roars, sings and twangs with the best of ‘em.
Tone junkies, beware – it’s about to get addictive
There is no latency, as nothing has to be calculated and converted from analog to digital and back.
The Spirit Tone Generator works at the speed of light, just like its tube forebears – well, actually about a 1/100th of the speed of light, but that will do for our purposes.
The point is that it captures all that lovely electrical chaos inherent in a tube circuit in such an addictive way that players find it very hard to put the guitar down.
Aim higher, sag lower
We’re not making that up. This actually happened when players started testing the prototype.
Their enthusiasm was wildly contagious, emboldening Bernd and the team to aim even higher.
Why not go beyond the preamp tube circuit to capture the behavior of the output stage, transformer, speaker, and even the power supply?
So they did, ending up with tone-shaping possibilities that the template does not offer.
Thus controllable sagging was born.
Well, here’s the short of it: a classic tube amp’s performance ‘sags’ when you do a Nigel Tufnel and turn the master up to 11.
Lots of cool rock-related stuff made millions of kids want to pick up an electric guitar; the sound of a sagging power amp is one of them.
But classic tube amps can only achieve this mixture of compression, creamier tone, and shimmering overtones at volume levels that can stun large and slay small creatures.
Soak or croak?
Now, a power soak attenuation system can convert a lot of this volume into heat – more on that here.
That works to a degree, but it’s not the same as a dynamic drop in power supply voltage.
It adds a flattish flavor to the tone that some players don’t like.
The sagging control made possible by the Spirit Tone Generator doesn’t do this.
It lets you dial in the sweet spot, that divine moment where a power amp sounds heavenly, just before it is about to cross over into the great beyond.
The Sagging knob on Black Spirit 200 offers eight stages of this bliss, from pristine clean to edge-of-destruction high gain.
You can dial this in as you see fit – without any unwanted side effects associated with microphonic tubes, ridiculous noise floors, over-the-top compression, and so on.
So, to belabor Ye Olde Cliché™, the Spirit Tone Generator really does combine the best of all approaches to guitar amplification – the tantalizing tone of the tube, the peerless reliability and lightness of the transistor, and the near infinite sound-sculpting potential of modeling.
All this loveliness comes latency-free and with a control feature array that’s essentially indistinguishable from that of a classic guitar amp.
The Spirit Tone Generator is the logical extension of what guitarists really want, paired with the possibilities, ideas and knowledge of our time.
Getting back to the bionics analogy, the biologist would call this an evolutionary leap.
First published: December 13 2018. Most recent update: December 13 2018.