Paul White, editor-in-chief of Sound On Sound, on life with his trusty Blues Cube guitar amp… This article was prompted by my quest for the ideal gigging amplifier. Some say that because I’ve suffered for my music, I make sure everybody else does too, but I couldn’t possibly comment! Although I’ve owned some really nice guitars over the years, until now I never really found an amplifier that I was entirely happy with. Valve amps always seemed too loud while modelling amps never quite gave me the quality of clean sound I was looking for, even if their overdrive sounds were perfectly fine.
“There is the option of buying a smaller valve amp and then miking it up for bigger gigs, but even small valve amps can be scarily loud once you’ve found their sweet spot.”
These days I prefer to steer clear of valve amplifiers for a number of reasons, some sonic, some practical. For a start valve amps are typically very heavy, the most affordable models based on printed circuit boards can be difficult to service, and because valves run very hot, components including the valves themselves can get overcooked. Valves need replacing fairly regularly, which can be expensive, and because valves deteriorate over time, you can never quite be certain that your amp is sounding exactly the same as it did at the last gig. The fact that different brands and grades of valves perform differently just complicates things further. Those are some of the practical reasons, but what of the sound?
It seems that the majority of classic valve amps only perform at their best over a relatively narrow range of volume settings, so if you buy an amp suited to large venues, you’ll probably find it sounds disappointing at lower levels, for example when playing in smaller pubs. Of course there are power soaks you can use to drop the amplifier power but most users would agree that they have some detrimental effect on the tone. There is the option of buying a smaller valve amp and then miking it up for bigger gigs, but even small valve amps can be scarily loud once you’ve found their sweet spot.
I came across the current Roland Blues Cube range when one arrived for review at Sound On Sound. Right away I liked the way that it was styled to look (though an optional tweed covered version would have been lovely) and to operate like a traditional amplifier with no menus or LCD windows, and I liked the fact I could carry it in one hand without discomfort. But the biggest surprise was the sound and, perhaps just as important to guitar players, the way it makes the guitar feel as you play.
It really did perform like a responsive valve amplifier but without excessive hiss or hum or those mysterious crackling, spluttering noises. I’m no stranger to modelling, both in hardware and software, but the Blues Cube didn’t feel like any modelling amp I’d tried before. A major criticism of many modelling solutions is that the dynamic response isn’t the same as with valve amps — you don’t get that little bit extra when you really dig in or that shimmery clarity when you back off the volume. With the Blues Cube there seemed to be a very natural interaction between amp and guitar. Sadly the review model went back, but it wasn’t long before I bought one.
Where are the other amps and Effects?
A typical modelling amplifier provides a choice of amp models, the ability to store presets and maybe some multi-effects, but to date those amplifiers have, to me at any rate, always sounded and responded like approximations of the real thing rather than as a true alternative. The detail in the modelling varies between manufacturers but a common approach is to break the amplifier down into blocks such as input stage, EQ, power amp stage and so on, then model each of these sections as a whole based on how that block performs rather than delve down to component level.
Roland claim that the technology behind the Blues Cube goes far beyond modelling, though strictly speaking it is still a form of modelling, albeit with a very detailed approach where all the clever stuff is done inside a DSP. Rather than approximate a load of different amplifiers, Roland’s designers instead concentrated on a single ‘tweed era’ amplifier and then not only dug down to component level but also modelled the interaction between components in extreme detail — all the way from the guitar input to the speaker output. The practical outcome is an amplifier with conventional controls that operates as you’d expect a traditional amp to work.
We’re told that the circuit Roland chose to replicate was based on a classic Tweed era amp that uses one 12AY7 and two 12AX7 valves in the preamp, a classic passive tone stack and a phase inverter feeding a Class AB push/pull output stage hosting two fixed bias 6L6GC power valves running into an output transformer. That amp’s power supply used a GZ34 rectifier valve, an important element when it comes to power stage compression.
Modelling the way a transformer output stage interacts with the inductive load of a loudspeakers is particularly challenging and a key element in how the instrument feels as you play it. A high-impedance FET input stage presents the correct load to the guitar while the solid-stage power amp section is driven via a high-impedance circuit designed to allow it to interact correctly with the speaker load where the fine-tuning of the amp/speaker partnership is done in the DSP section.
At the end of the chain is a custom 12 inch speaker, or in the case of the Artiste 2 x 12 model, a pair of them and we’re told that even the type of ply used for the cabinets was selected to enhance the tone. If you want a bigger rig, there’s also the Blues Cube Tour head and matching 4 x 10 cabinet, but for pub gigs with a full band, I’ve never had to have my Blues Cube Stage amp up past the 30 Watts setting. That’s sums up what Roland’s engineers tell us about the technology, but as a user, how does the amp really behave and how can you get the best out of it?
Does it Sound Any Good?
Whatever the technology under the hood, what really matters is whether or not these amps feel and sound like real valve amplifiers and to me they do, but with the bonus that the best sound is not limited to a narrow range of output levels. The preamp section can go from very clean without sounding clinical, via bluesy break-up to classic rock while power stage drive and even power supply compression due to voltage sagging is also modelled in a way that adds just the right sense of spring and compression to the sound.
“All of the amplifiers have separate Clean and Crunch channels plus a switch that allows both channels to be used together (Dual Tone) for a mix of cleaner and driven tones.”
To get around the ‘it’s still too loud’ problem, the power scaling control can go as low as 0.5 Watts. And yes, I have played a trio gig (no drummer of course) using that setting. Again the way of achieving the power scaling differs from the norm as we’re told it involves actually changing the power rating of the solid stage amplifier, but it really works and is something I rely on a lot when playing venues of different sizes as I can get that sense of a pushed power stage at any volume. It also allows me to get the right sound at studio friendly levels as (despite the very decent emulated DI output) I almost always use microphones to give me the most flexibility in capturing the sound of the amp. For most smaller gigs and for recording I favour the 15 Watts setting.
Other than the 30 Watt Blues Cube Hot, all of the amplifiers have separate Clean and Crunch channels plus a switch that allows both channels to be used together (Dual Tone) for a mix of cleaner and driven tones. These names can be slightly misleading though as the Clean channel can go from pristine, ringing clean to a light bluesy breakup while the Crunch channel can also be tamed at its lower settings. I’d say that without using pedals, the amps work best for clean-and-country sounds, smokey blues and classic rock. If you need a more modern metal sound, then just use a metal pedal – the amp can take it.
An optional footswitch can be used to switch channels and many third-party ones work just fine. Roland’s GA-FC Foot Controller can be used to access Channel Select, Dual Tone, and — where the amp has it, Tremolo/EFX Loop. As with many valve amps, each channel has a choice of normal or high gain inputs (almost everybody goes for the high gain one regardless of course) plus there’s a boost switch to ‘up’ the gain for guitars with weaker pickups or to add more drive. There’s also a bright Tone switch in each channel to add a useful amount of top — especially valuable with soupy sounding humbucking pickups.
To take full advantage of the modelled power stage and power supply interaction, you need to pick the power setting most appropriate to the venue so that you still have enough clean headroom and overall level but the effect of a pushed power stage still comes into play when you turn everything up. Some players like to mix a little clean channel with the dirtier drive channel using the Dual Tone switch, which helps keeps the dirty sound in focus, something you can do with a single button press or a footswitch. I haven’t mentioned the reverb yet, which might have been more attractive with a hidden switch somewhere to go between spring and plate emulations rather than being plate only, but the plate sound on offer is actually very musical and avoids spring ‘twanging’. Great for those reverb-soaked minor blues or just for taking the dry edge off the sound in highly damped rooms.
All the models include the same classic three-band EQ section and variable level reverb where the larger models also include a presence control and tremolo. Starting with all the EQ controls set centrally usually gets you in the right ball-park with a single coil style guitar though humbuckers may thank you for a touch more treble and maybe the top boost switch. I thought I’d miss not having a presence control on my Blues Cube Stage but I seem to be getting all the sounds I need without it.
Rear panel effects loop connections are provide on the larger models too but not on the Blues Cube Hot or on my Blues Cube Stage. Also worth mentioning is that on all models a USB direct recording port is included as is a suitably authentic sounding speaker emulated line output that can be used both live or when recording. This saves having to mic up the amp on stage if you need a little help from the PA. And talking of miking, for studio use I find that backing the mic maybe 300mm or so from the speaker grille gives the sound just a little bit more ‘air’ so if close-miking is your norm, give it a try and see if you like the difference. You can also change the recorded tone by trying different mics and/or moving the mic position between facing the centre of the speaker cone or the edge.
That’s all very well, but isn’t only one amp model something of a limitation? Well, if you have one amp you really love, why would you want to change it? Nevertheless, Roland’s engineers added a socket to the underside of the amp to allow the plugging in of an optional Tone Capsule — a piece of digital magic in a valve-shaped plastic dome. Each tone capsule was developed in conjunction with a ‘name’ player with a view to capturing their signature sound with the same meticulous attention to detail as the amplifier’s original Tweed emulation.
The range of Tone Capsules seems set to increase but already you can get signature Eric Johnson, Robben
Ford, New York (Oz Noy) and Ultimate Blues (Kirk Fletcher) capsules. These Tone Capsules completely change the character of the amplifier in the appropriate way (and the colour of the power LED), but I’m not going to let Roland get away without some criticism as, on my model at any rate, there’s no way to switch between the Tweed sound and the Tone Capsule sound. And plugging the capsule in and out all the time is not practical at a gig. Adding a switch on the Tone Capsule itself could address that for existing amplifiers, even if capsule switching is something Roland plan to add to future Blues Cube models.
Plays Nicely with Pedals
If you use pedal effects such as delay, then you have a choice as to how to deploy them. Delay invariably sounds best coming after distortion so on the larger amplifiers, it makes sense to put your delay in the effects loop if you use the amp itself to shape your overdrive sound. However, I find that a Blues Cube makes a great partner for overdrive pedals. If you set the clean channel gain so that you’re just getting a hint of breakup with the guitar volume at maximum, kicking in the pedal will produce a wonderful classic rock tone while with the pedal turned off, you can back off the guitar volume slightly to get a really valve-like clean tone with natural warmth and compression. So many other modelling solutions seem to produce a very lifeless or sterile clean sound with the guitar volume backed off, but not my Blues Cube.
I use a couple of different drive pedals on my board and set the amp up with the gain at around half way on the Clean channel, which allows me to put all my pedals before the amp where my delay comes at the end of the chain. This turns out to be a very versatile way of working; I can call up rock, country or pop sounds very quickly, all without having to touch the amplifier.
As most lead sounds set using pedals include a touch of added level, the overdrive sound you hear is actually a combination of pedal overdrive plus the front end of the amp being pushed a little harder. I find this sounds better than using the amp in ultra clean mode and then relying on pedals for all of the overdrive so it is worth experimenting with the clean channel volume to find the sweet spot.
For pedal users who play mainly small gigs, or even larger ones where the amp can be fed through the PA, the single channel Blues Cube Hot could be a good choice. For those with simpler needs, a Blues Cube Stage or above used with a channel switching footswitch might be a practical option as you can get a wide range of classic sounds without needing any pedals at all, though you’ll need to move up to the Artiste if you want tremolo as well.
There are still some wonderful valve amplifiers out there and of course some of them can be tempting, but for what I need to do in the real world of mainly pub and club gigs where I need a consistent sound over a wide range of volume levels, my Blues Cube meets all my practical needs, it sounds the same every time I switch it on and it makes the guitar feel right in my hands. What nailed it for me was the natural compression and ringiness of the cleaner sounds, the touch responsiveness, those ‘just breaking up’ blues tones that you can really dig into and the way the amp co-operates so well with pedals. And when playing gigs accessed by a three story fire escape, I really appreciate the weight.
For years I’ve been frustrated by the limitations of both valve and modelling amplifiers but for me my Blues Cube ticks all the right boxes ( though I still look back fondly to the days when amps came with covers rather than having to buy them as optional extras) so I don’t think I’ll be looking for a new amp any time soon. To put things into context, yes there are many cheaper modelling amplifiers on the market but if you think valves are the only way to go and you care about tone and feel, especially at the cleaner end of the spectrum where these details really show up, then give one of these amps a try as it might well change your expectations. It did mine.