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Roland MC-50 MkII midi sequencer - tips, tricks, bugfixes, upgrades.

Sept 2014

I started midi-sequencing on this machine back in 1992, using it's audio sync signal (known as FSK) to lock it to an 8 track reel-to-reel tape recorder. The MC-50 was the nerve centre of both my midi gear, and (via CV and DIN sync converters) my pre-midi gear, keeping everything playing together. Hooked up to a midi keyboard and a midi fader box, writing was fun and fast. The keystrokes became second nature, so even while editing midi data you seemed to stay in the creative zone. The tape sync rarely failed unless there was a problem with the tape. It never crashed.


Software replaces hardware

By the early noughties, hard-disk recording on a home computer became affordable, and the possibilities were incredibly exciting. So, inevitably, the MC-50 and the tape machine gave way to a computer-based sequencer, first Cubase, then later Ableton Live, what is now called a "DAW".
Almost immediately, I noticed tempo sync problems. The clock pulses coming from the computer were nowhere near as tight and precise as the hardware had been!
Moving from Cubase to Ableton Live provided no improvement in the timing department. The jitter in the tempo clock got correspondingly worse the busier the Live set became. Worse still, the way midi was implemented in LIve 5 (my main composition DAW) seemed incredibly clunky, and heavily mouse-dependent. Ableton Live deserves it's reputation as an amazing tool for manipulating audio, however the midi side seems to have been an afterthought.

The frustration caused by these problems caused me to look for ways to use my old MC-50 alongside Live 5, to give me the best of both systems. As I've said, just slaving the hardware to the software via midi clock proved way too sloppy. Luckily around this time I became aware of the great work done by David Lackey at Innerclock Systems. He was promising to deliver a box that read an audio pulse from a track on the DAW, and put out sample-accurate midi and din sync clock pulses. This got me thinking. What do all DAWs have to give priority to, first and foremost? The simultaneous reproduction of multiple audio tracks down to the sample level. So it seems logical that generating the sync signal at the audio level, rather than the midi level, should give you much more accurate timing.
So I looked at techniques for generating an FSK sync signal - yes, good old tape sync - as audio from the DAW to the sync input on the MC-50 hardware, bypassing midi altogether. For some reason just sampling the FSK signal didn't work very well, but generating the pulses from a soft synth triggered by a midi file did work. The technique is not without it's limitations, but has proved to be a qualified success - details here.

Hardware is back on the team

So, now I had sequencers old and new, hardware and software, locked together in tempo, with the DAW as the master.
Great - but really, you ask, why bother?
Well, as I mentioned at the beginning, the reasons are fun and speed.
Keystroke commands can be so much quicker than using a mouse. They are generated at a lower level of brain architecture, and so have a less disruptive effect on conscious attention, allowing it to focus on the creative effect of the task. Using a mouse engages more parts of the brain, and at a higher level of architecture (e.g. optic cortex needs to track the pointer, and relay this information to the motor cortex controlling the mouse-hand). The result of using keystrokes is a feeling of freedom and flow when creating and editing midi parts. Of course, this assumes you have put the time in to read the manual and acquire the skills in the first place. The time spent is always repaid well.

Some key commands on the MC-50 make workflow extremely fast:
• [PAUSE] + [RECORD] allows you to start recording (or erasing) from the very tick (one tick is a 96th of a quarter note) that you are stopped at.
• UTILITY 8 (tune) sends an A4 note on all channels when you need to check audio connections or tune your analogue synths.
• [STOP] + [MIDI] sends an All Notes Off message on all channels.
• [PAUSE] + [MIDI] updates all pitchbend and CCs up to that point in the song.
• Hit [LOC] and a number to jump to a Locate point, hit [LOC] + [REC] then a number to set a Locate point right where you are.

x0x style

For rapid rhythm pattern recording, the MC-50 uses the classic old Roland step-write-while-running style of a TR808 or a TR909, with eight levels of accent. Its quick and intuitive even just using the 2 line display and the key pad, but it's even better if you are using a midi controller keyboard with a sustain pedal, as this allows instant erase of any particular voice by holding the key down with the pedal depressed, while the pattern loops. This is a very fast way of writing/editing rhythms - shame they are only one bar long! But once you write them into the  Rhythm Track, you can quickly copy them into a "Phrase" track (a Phrase track is everything else that is not a Rhythm track) to allow sophisticated editing/quantizing that simple pattern writing doesn't allow, so you start simple, then get busy. The screenshot below shows a closed hi-hat pattern of sixteen steps, the numbers representing the note velocities.


Composing quirks

The MC-50 allows an interesting type of midi composing, reminiscent of Roland pre-midi products such as the MC-202 and the TB-303, whereby you can at first enter, in step time, the notes or chords you want to use, without worrying about their timing position. Then, once they are entered, you can then write, in real time, the velocity/step/gate time of those previously-written notes or chords independently of the actual note values. (Roland's name for this is the snappy "MODIFY RECORDING").
So lets say for example, you have some piano chords you like the sound of, and want to try them out over a house track. Enter the chords in STEP time, just one after the other, don't worry about the note values, then in REAL time, using just one key, try tapping out some rhythms til you find one that works. After that, you can adjust the note velocities, again in REAL time, with the mod or pitch wheel if you like. Fun and fast. Another example: input a handful of notes triggering percussion samples in step time, then in real time send it the midi notes of a groove or a drum machine pattern that you want your sequence to conform to.
A simple but surprisingly creative instant-gratification feature are the mute buttons. There are mute buttons for the Rhythm, Tempo, and the eight Phrase tracks. These allow on-the-fly arranging while you are synced to your DAW... Ableton can only beat this for fun if using a fancy control surface.


The "Super MRC" type of Roland sequencers, such as the MC500/MC500mkII/MC50/MV30/JV1000 etc, are amazingly reliable and free from crashes. But there are two bugs that I'm aware of, the "loop" bug and the FSK bug.
When the unit is externally synchronized to either "Tape" or "Midi", and it is then put into "loop" or "cycle" mode (the term Roland uses is "BLOCK REPEAT"), it gets increasingly out of sync as it loops. Analyzing this, I have discovered it is because it "loses" a single tick when the loop rolls around again from the end point to the start, causing the timing lag to increase with every cycle. Therefore the fix for this bug is to specify the loop points, not by bar number, but by [LOC] (locate) points. This allows you to set the points down to single tick resolution. Place the first LOC point at the 00 point of the first bar, and the end [LOC] point one tick less than the end of the last bar i.e. at beat 4, tick 95, of the last bar. And so by holding [SHIFT] while hitting [PLAY], loop play will start when the external clock arrives, and continue to play the loop indefinitely, accurately locked to the DAW.
The FSK bug happens when you send the unit FSK signals to the sync in jack, while it happens to be playing under internal tempo, and not external clock. The LEDs will flicker, playback will stutter, and the unit may freeze up. This is cured by stopping the FSK and hitting [RESET].

Floppy upgrade

These machines are now over 20 years old, so their floppy disc drives may be starting to get a little flakey. Mine certainly was, so I replaced it with the HXC Floppy Drive Emulator, which was a fairly straightforward drop-in replacement. There are other options around such as USB floppy emulators, but they may not be able to provide the data in a format that the MC series can recognize. The HXC system has great support and been proven to work.
Details and images of the replacement are below.


Incredibly, despite years of use, my machine has needed no major work. However, some of the buttons are getting a little intermittent, so I thought I would take a look at them to see if they were accessible to a bit of cleaning. A detail of the switch is shown below. Unfortunately, there was no obvious way of getting the switches open to clean them, so I'm still investigating this.

Under the hood

To open the MC-50 for servicing or upgrades (qualified personnel only!): Unplug all connections and flip the machine over to rest it on some thick cloth or foam, to prevent damage to the screen, alpha dial and buttons. Then, remove all screws on the rear and underside of the machine. Make careful note of which are the metal threads and which are the self-tapping threaded screws. At the rear panel there is one screw longer than all the others. You can use a graphite pencil on the case, which can be rubbed off later.
Once this is done, slide the base rearwards so that the jacks and power button can get clearance, to allow the base to be lifted up and away.


Replacing the floppy disk drive

Note the orientation of the two connectors on the floppy drive. The ribbon cable has a coloured wire that denotes Pin 1. The power cable has 2 ground wires and a 5 volt line, the fourth connection is absent. Disconnect them. Unscrew the mounting brackets holding the FDD in the unit, and lift it out.


Use the same mounting brackets to hold the HXC hardware. I had a bit of trouble here - the casing of the HXC (made by Lotharek) is so tough, it flattened the threads of the original metal-thread mounting screws. I had to resort to self-tapping screws with deeper threads.


Connect the cables. The 5 volt power line is marked on the HXC, as is Pin 1 of the ribbon cable connector.

Now, flip over the HXC, ready to screw the mounting brackets back to the chassis.

The HXC LCD displays an image of a floppy disk, ready for use with the MC-50:





Text and photos copyright © Adam Inglis 2014


MC-50 panel switch jpeg

Floppy upgrade