Though ready and willing to take full advantage of all that the digital tone modeling revolution has to offer, like many guitar gearheads, I fall back on my trusty tube amps and analog stomps when it's time to get serious. Color me intrigued, however, when Yamaha's two-strong THR Series solid state combo amps hit the shelves at the beginning of last year – featuring the company's Virtual Circuitry Modelling (VCM) technology for authentic-sounding tone, even at low volume. Three new models made a U.S. debut at the Winter NAMM Show back in January 2013, and I've been discovering exactly what VCM tubes sound like with the THR10C solid state boutique home/studio amp.

In the box

  • THR10C guitar amp
  • AC adapter
  • USB cable
  • Stereo mini cable
  • Owner's manual
  • Cubase AI 6 DVD

Before I dive into a review of this amp, a word or two on Yamaha's VCM technology. The company says that its software environment allows its engineers to digitally model amp circuitry at the component level, creating virtual clones of resistors, capacitors, tubes and so on. The finished solid state amp offers what's claimed to be authentic vintage tube-like tone.

A number of companies have made similar claims for digital processing, but the results are often less than satisfying so I opted to play Devil's Advocate and asked my technical contact at Yamaha to explain what made VCM different.

"We use the physical modeling technology originally developed for the VL1 synth in 1993 (the world's first commercially available physical modeling instrument) to accurately model the behavior of each component in the signal chain," Yamaha UK's Julian Ward told me. "So instead of using our DSP power to shape and equalize the output of our guitar amp circuit (what most modeling amps do), we use a fundamentally flat-response audio circuit and deploy the DSP to model each component in our virtual amp circuit. By doing this, the bi-product is the tone of the analog circuit we've digitally created but beyond the tone, we also get the musicality of an analog circuit because the physical modeling technology is capable of modeling the non-linearity and signal loss associated with analog circuits."

"What that means in the real world, is that the amp models in THR actually respond like a tube amp – from the fact that turning up the master volume changes not only the loudness, but also the tone, compression and distortion characteristics to the fact that the amp responds to picking dynamics and attack in the same way as a cranked tube amp – because our VCM algorithms are capable of reproducing the way individual, analog components actually effect and interact with both the signal passing through them and each other," he continued. "But even with the capability of modeling the behavior of individual component types, VCM isn't a carbon-copier for amp circuits – the algorithms need to be hand-tweaked and fine-tuned by an engineer who understands how the real component and circuit would react."

"This is another unique element of THR's amp models," added Ward. "While they are based on classic amps as a starting point or reference, they're not designed to be a perfect simulation of another amp. Instead, our engineers create the best sounding amp based on that type of circuit they can make – just like amp modifiers like Mesa Boogie, Splawn and a host of other boutique amp companies (who mostly started by making amps based on either modded Fender or Marshall designs) – but our engineers have a VCM software toolkit instead of a box of components and a soldering iron."

A quick tour of the THR10C

The new home/studio amps retain the original THR shaping that lends a vintage radio feel rather than the more familiar square box practice combos like my 15 W Marshall shown below. The dark blue THR10C has dimensions of 360 x 183.5 x 140 mm (14.1 x 7.2 x 5.5 inches) and weighs a portable 2.8 kg (6.1 lbs). It's powered via an included AC adapter or six AA-sized batteries (not included) – the alkaline variety claimed to offer up to six hours of use, while Nickel-hydride cells will get you an extra hour or so. There's a chrome carry handle to the top for ease of transport.

Staying topside, a rather nice retro power switch to the left serves to illuminate two orange/red LEDs inside the grille to bring home its tube/valve emulation credentials. The lights also reveal two 8-cm (3.15-inch) full range speakers with bass porting through the slots, promising true Hi-Fi stereo sound at a total rated output of 10 W. The THR10C benefits from a DSP developed in-house by the company's Semiconductor Division, 24-bit A/D and D/A conversion and a sample rate of 44.1 kHz.

Moving left to right along the top, you find five user-assigned memory buttons, a small LED display and a tap/tuner button. The tap function allows the user set the tempo of the repeat (by tapping more than twice) when using the unit's delay effects, and the chromatic tuner function is engaged by pressing and holding the button for one second. Holding down the switch for more than three seconds activates the unit's extended stereo function, which expands the stereo image for a far more spacious feel than you'd think possible from such a small unit.

Next up is the Amp knob, which allows selection of Deluxe, Class A, US Blues, Brit Blues or Mini amp emulations, or Bass (fat bass tone), Aco (electro-acoustic sim) or Flat (flattened out clean sound) – more on these later. The Gain and Master controls work in a similar fashion to the preamp and master controls on a tube amp – the former dials in preamp gain/distortion, while the latter oversees power amp level.

Bass, Middle and Treble EQ follow, leading into two banks of onboard effects. Players can choose from either chorus, flanger, phaser or tremelo modulation effects for some extra tonal spice, and four different ambient delay/reverb simulations, including tape echo and spring reverb. The more you move the knob clockwise, the greater the influence of the effect within its block.

The last two control knobs deal with output volume. A Guitar control caters for adjustment of the instrument's output via the amp's stereo speakers, and next door is a USB/AUX output knob for playback level control of any music player plugged into the auxiliary jack or USB-connected computer.

Confusingly, the user manual states that the unit's Master volume control "only adjusts the volume when Bass, Aco or Flat is selected with the AMP control" but this is not the case. The Master needs to work in conjunction with the Guitar output knob to pump out sounds from the speakers. This actually seems a little odd at first but does allow for more precise control over the output volume.

At the far right is a 0.25-inch instrument input, a 0.25-inch stereo headphone out jack and a 3.5-mm auxiliary input. Completing the tour is a USB port to the rear, situated next to the AC power input.

First play

The five main amp emulations are based on tones from existing, real-world amps but are not intended to be exact copies.

"I think a lot of players are looking for what they think an amp sounds like rather than what it actually sounds like," said Ward. "Lots of these amps are actually quite hard to get a good sound from (unless you're John Mayer, Joe Bonamassa or Eddie Van Halen playing in a great sounding room with amazing mics, recording equipment worth millions of dollars and a top-class engineering/production team). Is it better for us to attempt to create a totally accurate replica of the sound and response of a DC30 (or whatever) or just make an amp that has that vibe in terms of sound and response and is fun, engaging and easy to play? Of course, there's an argument for both, but for what THR is designed for (essentially a high-end practice amp, not a pro toolkit) we decided on the latter."

The five main THR10C emulations are based on real-world amp circuitry as follows:

"We're all players and love a bunch of different amps so had an idea in our heads of 'a sound something like ...' when we were deciding what we wanted the THR models to sound like," added Ward. "The bottom line is that only a DC30 sounds like a DC30 – we're not trying to claim the THR10C mimics that, these amps gave us a starting point for a tonal signature to aim at."

Given this varied ancestry, it will come as no surprise that each of the five main Amp selections sounded markedly different, but they all have one thing in common – they made my solid state amps sound very ... well, solid state.

The Deluxe offers a beautiful clean sound that seems determined to resist all calls to get down and dirty. The Class A dials in some warm – but not too overpowering – distortion/gain and features a responsive EQ that takes some mastering (a tweak on the Bass, for example, will also affect the blend of the Middle and Treble). The US Blues setting is great for those Freddy King moments, and the Brit Blues produces a not too shabby homage to Slowhand's unmistakable Bluesbreaker tone – even down to the EQ knobs not having a great effect on the overall sound.

As a dedicated fan of fuzz though, my favorite of the five was the Mini. Unlike its real-world ancestor, the THR10C's circuit offers full EQ and both Gain and Master blending. The quite impressive range of gorgeous textured distortion grunt available made for quite lengthy metal-tastic adventures.

Of course, the 3.5-mm auxiliary input also means that you can feed in music from your MP3 player and jam along to your favorite artists or rehearsal/studio rough cuts. As the hardware is made by Yamaha Hi-Fi, the audio reproduction is actually pretty decent and loud enough for most home use settings.

When is a tube not a tube?

So, has Yamaha found that elusive Grail of digital simulation, and nailed the tube amp once and for all?

"Digital amps may not be able to 100 percent accurately model the exact behavior of a tube circuit, but I would say that all digital technology is not equal and with VCM physical modeling we can get close enough, in practical terms, that the majority of players won't, in our opinion, notice or care," said Ward.

I find myself in agreement here. Of the genuine, real-world tube amps that inspired Yamaha's THR engineers, I've only actually had the opportunity to play through two of them – a Deluxe Reverb (albeit a 65 reissue) and a vintage Bluesbreaker. I have heard other players using the remainder, though, and the THR10C succeeds in sounding very much like the kind of tone you might get from them. There were even startling moments when the emulations managed to capture the essence of my own tube amps.

Like classic tube amps, each of the virtual amp circuits in Yamaha's boutique home/studio amp proved quite responsive to the controls on the guitar and, in an interesting twist, the character of the available ambient and modulation effects also changed in keeping with the chosen Amp setting. When all's said and done, though, the THR is not a tube amp.

"Sure, you could argue that the response of our Mini model doesn't have the exact same sound or response as a 1xEL84, 1xGT12AX7M, 1x10 combo but then my response would be threefold," Ward told me. "First, if you want the exact sound you get from a Dr Z Mini Z, buy a Dr Z Mini Z – but good luck using it as a USB interface or getting that tone in most situations without getting dumped/divorced/arrested. Second, change the power tube in that amp (or even the venue you're playing in) and the sound and response will probably change – what that amp, or any other tube amp, sounds like isn't static or perfectly predictable – it's just about having a great sound and a good response. Which leads me nicely onto the final point: Whether or not the models in THR are good sounding, usable amp models? We believe so – the obsession with digital versus tube or whether an amp model sounds like the real thing is a bit of a moot point to us, what actually matters is how your amp sounds and plays."

One step beyond ...

As touched on above, the THR10C can also be hooked up to a computer with the help of the onboard USB port and the free-to-download Yamaha Steinberg USB driver. Without doubt, one of the most compelling reasons for doing so for tone junkies like me is the ability to go under the hood and further tweak the amp's parameters via the THR Editor. This software allows users to add otherwise hidden signal processing to the output, to choose from different cabinet configurations and store favorite patches to the library for later recall.

In addition to stomp or rack compression and a noise gate, the settings of the amp's included effects can be altered to personal taste. Rather than storing the rather pleasant tremelo sound I had managed to create (similar to the guitar heard on the excellent Cotton Patch Hot Foot by Big Walter Horton) in the library, I stored it in one of the five available slots in the user memory bank on the amp itself. This allowed me to recall these settings even after disconnecting the amp from my computer. A nice touch.

The THR10C also comes supplied with Cubase AI 6, a stripped-down version of Steinberg's powerful full music production suite. While installing Cubase AI was relatively straightforward, the registration process was another matter. I can understand the need to protect expensive software from piracy, but activating and registering using the necessary eLicenser package felt overly complex and somewhat clunky. Perseverance paid off though, as the software certainly proved to be worth the effort – although going into detail of precisely how it's used is perhaps beyond the scope of this review.

One excellent feature worth mentioning is the wet and dry USB signal that's simultaneously sent to the computer from the THR. The wet signal includes all of the effects, tone tweaks and amp simulations that you've chosen to include, and the dry is a straight, clean DI signal. The latter proved very useful for post processing of recorded output. If, for example, you nail the rhythm but want to change the effects used on the lead break, the DI signal can be fed back into the THR, new effects applied and the revised lead break spliced into the track without having to re-record the whole thing.

The bottom line

The THR Series was created as something that would meet (or even surpass) the off-stage needs of a player, sitting somewhere between cheap-and-cheerful practice amps and the big volume stage amps.

"We were trying to keep in mind the core things that we felt such an amp had to have: genuinely high-end, 'real-amp' sound, response and feel (at home-friendly volumes); the ability to integrate into a player's setup off-stage; usefulness for the actual application that it was designed for," revealed Ward. "We figured that an increasing number of people playing at home were doing so either at some kind of desk, or in a decidedly domestic situation such as on the couch. This was a big drive for the shape and style of the THR enclosure – the cabinet designs of most other guitar amps (and most small amps are literally just down-sized versions of big amps) are based on projection and dispersion characteristics needed for live performance and, as part of this, they're always designed to be used on the floor – something that's a pain at home."

"And while some people may have the luxury of being able to stand up, six feet away from their amp when they're learning a song or jamming to a track on YouTube on a Thursday night, it certainly isn't the majority," he added. "So we made THR in a configuration (and therefore shape) that would work for how we figured people were actually playing (or wanting/needing to play) – with their amp at roughly ear-level (on a desk or table) and projecting a short distance, not to start coming alive ten feet away from the cabinet. The fact that the shape is roughly the same as a small 'lunchbox' head is, to be honest, a happy coincidence."

I have to admit that, being someone used to those floor-based amps, I didn't immediately warm to the design. Once switched on and plugged in, however, the THR10C soon had me convinced. It starts by drawing you in almost immediately with its eye-catching LED lighting behind the grille, but it's the extent of control over the tone/volume blend that was the first obvious winner for me.

Though die-hard tube fans might beg to differ, the fact that it isn't a real tube amp doesn't really matter. Yamaha's versions of the five tube amps included with the THR10C show an impressive attention to detail, something that follows through to the onboard effects (particularly the Tape Echo).

Anyone who has enjoyed some one-on-one time with a powerful tube amp will know that the harder you drive it, the better it sounds. At just 10 W rated output, this amp is not going to give you anywhere near the same ear-damaging volume, but its VCM technology does seem to offer a similar big sound feel at a much lower output.

Throw in the ability to fine-tune the supplied tones and effects even further using the Editor, together with the included Cubase software package and its ability to act as a very capable speaker for a music player, and I think that Yamaha has got itself a winner with the THR10C.

Available now with a street price in the region of US$299, this is probably not going to be something that you learn to play guitar with. Quite rightly, in my opinion, it will likely find a home with musicians looking for something that can give a vintage low gain, hand-wired boutique amp sound in a small and lightweight package.

The THR10C is joined on Yamaha's new product podium by the THR10X (for an extreme gain, stacked amp sound) and the THR5A (which offers simulations of classic tube condenser and dynamic microphones and studio-grade effects for electric-acoustic players). The original THR10 and THR5 are also still available.

Product page: THR10C

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