The Roland Mobile Cube is a small battery-powered portable stereo amplifier, with built-in speakers.
Initially, I bought it for use with a laptop and Propellerhead Reason, so I can work on music ideas anywhere — but it’s capable of quite a lot more than that.
Audio Inputs and Controls
The left hand side has three 1/4″ jack sockets.
The top one is a microphone input, which has it’s own volume control on the top.
Below the microphone input are two sockets that can act as left and right stereo inputs. Or you can just use the left input for mono sources such as guitar. These inputs are controlled by associated switches and a separate volume knob on the top. There are settings for acoustic guitar, electric guitar (clean, overdrive and distortion), audio, keyboard (normal and fat). Basically, the different settings have different EQ, and in some cases effects. The audio setting gives a flat response.
There is a button for chorus, but Roland didn’t manage to find room for a variable control for this. The chorus effect is perhaps a bit too heavy-handed.
The final inputs are auxilliary, with both a 1/8″ stereo jack socket, as well as left and right RCA phono sockets. I was a bit surprised that there is no volume control for these inputs. So you need to drive them from something with its own volume control, such as an iPod, and you need to make sure the volume is not set too high before you begin!
I’ve found that you can use both inputs at the same time, although this is not discussed in the manual. I suspect there’s a simple passive mixer for the two inputs. (They’re not simply wired in parallel — I’ve checked with a multimeter.)
The button marked ‘aux center cancel’ attempts to remove sounds in the centre of a stereo image, such as vocals or guitars. The idea is to enable you to do karaoke or play along. This is not something I’ve really used, and it’s effectiveness will vary widely from one recording to another.
Everything except the aux input is routed through the tone, delay and reverb sections. The delay and reverb effects can’t be used at the same time — they share the same control knob — but they are both adjustable. The single tone control is useful, but it would have been nice to have something a little less basic, such as separate bass and treble controls.
Power comes from 6 x AA batteries. The manual says that you should only use alkaline types, but I’ve found that Ni-Mh rechargeable types work fine too. Roland say that you’ll get 15 hours continuous use from a set of batteries, but in practice at high volume levels, it’s more likely to be just a few hours.
I suspect rechargeable types might not last quite as long, due to their slightly lower voltage, which probably results in the amplifier shutting down before all the available energy has been used. You don’t really get much warning that the batteries are running low — the main thing I’ve noticed is that the power LED glows a bit less brightly.
You can also use a mains adapter. Roland say that you must use their special adapter, but I found a suitable third party one on eBay. The mains adapter is slightly non-standard, in that its output polarity is reversed compared to most.
On the right hand side, there is a 1/8″ headphone socket. As you might expect, using this cuts off the internal speakers. While not as good as a dedicated heaphone amplifier, it still does a decent job of driving headphones, including my trusty Beyerdynamic DT880 Pro 250 Ohm.
Below the headphone socket, there is a push-button power switch, and finally the power input for use with the mains adapter mentioned earlier.
Although it’s quite small, The Mobile Cube does feel surprisingly chunky and solid.
The overall size is 280 x 108 x 177 mm (11 1/16 x 4 1/4 x 7 inches).
It weighs in at 2.5kg (5 lb 9 oz).
Being battery powered, it’s not hugely powerful at 2.5 W per channel.
But the two 4 inch speakers seem to be efficient, and manage to produce surprisingly decent levels. When you drive it too hard, it behaves in a somewhat unusual way by cutting out briefly, which can be annoying.
Overall, I’m very happy with the Roland Mobile Cube, and have no plans to sell it.
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