SX-150 Mark II

I’ve been holding off from getting the SX-150 Mark II because of the 7,350 yen ($90 USD) price tag.  However, I did get a bit of a windfall from some piecework recently, and given how hard it was getting to the bookstore on crutches from the school I work at, I figured that I’d kill two birds with one stone – buying the Jansen DVD and the Mark II at the same time.

(The original SX-150.)

The Mark II is an enhancement of the SX-150, also known as the Synthesizer Chronicles special kit. The original “Chronicle” was a kit that you had to assemble, and included the mook.  Variable controls were for LFO Rate, Attack, Decay, Pitch Envelope and Cutoff.  The three switches were for Resonance ON/OFF, LFO Wave (square or triangle) and Power (Off, Low Volume and High Volume).  The External Source jack allowed you to drive the kit from a voltage source instead of the resistive strip. The build-in speaker was very tinny and thin, so using the Output jack to drive mono headphones or run audio to a mixer was a much better choice.  The good part of the kit was that it was cheap – 3,360 yen, and that made it easy to justify modding it.

(Mark II. It’s about 6″x4″x1″)

The Mark II builds on the original, replacing the Resonance switch with a variable control, and adding an LFO Depth control.  The power switch has been changed to Off, On and Gate; where Gate disables the Attack and Decay controls.  The External Source jack has been relabeled as “Line In”, but probably works the same way.  Finally there are two new pressure-sensitive push button switches: VCF Modulation and LFO Modulation.  The tiny built-in speaker is still mostly pointless – you’re better off plugging headphones into the Output jack instead.  The Output audio is pretty rich and clear in comparison.  Now, this is not a kit; basically you just get a small box that contains the Mark II, a sheet of silvery labels for customizing the knobs, and a foldout sheet with warnings (don’t play the Mark II in the shower, and don’t leave it in your car with the windows rolled up in the summer) and brief descriptions of what each of the controls do. It’s the same descriptions found in the highlights page on the website.

The one thing I really do miss from the Synthesizer Chronicles mook is the suggested list of control presets (patches) for making different kinds of instrument sounds.  You’re kind of left on your own this time.  Although, the Otona no Kagaku site does have a selection of youtube videos demonstrating the use of each of the controls.  One of the first things they did was to draw a piano keyboard layout on a piece of paper and tape it next to the resistive strip, which makes it easier to figure out where to put the stylus to play any given tune.

(Tuning control is at the top right.)

Right out of the box, the Mark II was really high-pitched, with a limited frequency range.  Initially, I thought it was because of the control knob settings and I was resigned to spending time trying to figure out how to get bass sounds.  But, I decided to look over the instruction sheet first, and immediately noticed that there’s one additional control on the bottom of the case, marked “Tuning”.  This is the control that adjusts the frequency range for the resistive strip, and is so incredibly powerful that I’m stunned that they didn’t put it on the top of the case with the other knobs.  If you intend to use the Mark II in live performances, and there’s no reason not to mod it to do so, then you’ll REALLY want to get to Tuning without having to turn the box upside down.  Gakken should have left out the speaker and put the Tuning control in its place.

Given the price of the synth, the construction of the two modulation switches is rather cheesy.  There’s no real force feedback, you have to listen closely depending on the waveform. being produced, to tell if the LFO Modulation button is even doing anything. The amount of pitch bending you get is dependent on a very small range of pressure on the switch.  The VCF Modulation is much louder and easier to sense, but still has a narrow pressure range.

Because Tuning has such a big impact on the final sound of the synth, in combination with the other controls there’s a relatively steep learning curve.  I expect to be kept entertained with it for a few weeks just trying to see what sounds I can get from it.  After that, I’ll want to replace the resistive strip with something a bit easier to control consistently, make the Tuning control more accessible, and see what Line In does.  If you’re in Japan, get this kit, it’s a good introduction to monophonic analog synthesizers.  Otherwise, the import markup makes it less attractive, unless you’re a professional musician and want something unusual to add to your tool set.

Note: If you want to hear the kit, check out the Otona no Kagaku youtube videos.

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