Category: Equipment (Page 1 of 10)

Time for another post in the series on Roland A-80 MIDI Keyboard Controller servicing. Previously:

• The Roland A-80 arrives
• Changing R43 to make the aftertouch more responsive
• Replacing the key bed “upper” felt
• Replacing the D4 key’s rubber dome switch
• Replacing the LCD display

The short:

• Use Velostat to replace the pressure-sensitive cells under each key.
• Change R43 to a variable resistor of about 27k and set it mid-way
• Enjoy.

The longer, illustrated version

Despite the R43 fix, the touch response has never really been usable. The mechanism Roland used clearly didn’t remain viable over time. The risk of screwing up the key bed completely has always deterred me from experimenting in this area.

And then, there was this thread on Computer Music Guide forum, “Roland A-80 (Aftertouch Repair)”. Back in 2014, noisevoid had the great idea to experiment with alternative pressure-sensitive rubber to see if they could restore touch-sensitivity to the notoriously unresponsive A-80 key bed. Their research identified a product from Zoflex as a possible solution…. and then they were never heard from again on that thread.

But the idea intrigued me, and after Syntaur alerted me that the “upper” key felt strip was back in stock, I decided it was time to go deeper. I placed an order for a sheet of the Zoflex product… and also did more research on pressure-sensitive materials.

One finding in particular looked very interesting: In 2016 Liam Lacey had implemented a “toy keyboard synthesizer” with pressure sensitivity using a product called “Velostat”. Intrigued, I ordered a sheet as an alternative.

Eventually the samples showed up. The Zoflex rubber sheet was about 1mm thick and quite “spongy” and quite expensive for a 10cm square sample, in beige. The Velostat sheet was larger, more like an A4 sheet of paper, and much thinner. And cheaper.

Here’s the plan:

• Replace R43 with a variable resistor to allow for sensitivity adjustment
• Remove the keys and the upper felt strips
• Lift the plastic pressure strips enough to insert samples of alternate product
• re-assemble loosely to test response

Replace R43 with a 100k variable PCB mount resistor

There’s no getting around it. Main Board A has to come out for desoldering. I’ve covered this process before. Six screws and several connectors need to be removed.

The odds of an alternative variable-resistance pressure membrane “just working” with the current 56k value seems unlikely. I obtained a small PCB-mount 100k resister and snipped off one of the outer legs. This gives us a replacement for R43 that will let us alter the resistance. I wasn’t sure this step was necessary but it seems prudent.

With that done, I re-assembled Main Board A back into position.

Remove the keybed assembly

Probably best to review my previous post on the subject.

Digression: The Key Press Action

I created this animated GIF showing the mechanical action of a key press:

As you depress a key, the first thing that happens is that the grey rubber dome switch is activated. (You can see it on the right.) It has two contacts in it that closes two circuits in quick succession, indicating Note Velocity.

On the left you can see two felt strips that run under the keys. The black keys rest on the right-hand strip. The white keys rest on both strips. Under the felt strips are circuit contacts for each key press (white on the left, black on the right). Each contact is covered by a small rectangle of material that changes resistance with pressure. So, as you push down on the key, the resistance change is detected and translated to note pressure or “aftertouch”.

Remove the keys

This is where a key removal tool becomes very handy. I’ve actually made a short YouTube vid of the process:

With the keys removed, we can start finding out what is under those felt strips.

Remove the felt

At this point, my recommended procedure diverges from what I actually did. I was cautious and also not sure of what my next step would be. I wanted to remove the felt strip but leave the pressure strip in place. Also, I wasn’t planning on re-using the original felt strip, at least, not all of it. I figured I had a replacement strip that could be used for either the white keys or the black keys. I thought I only needed to keep 50% of the existing felt strips in re-usable condition.

The adhesive between the felt strip and the underlying plastic strip is quite strong and it was an awkward process to remove the felt intact while not also pulling the plastic strip away from the PCB. I really wanted to leave as much undisturbed and original as possible.

With the felt removed, we can see the plastic strips under which the pressure-sensitive resistive pads are mounted:

In hindsight, knowing that I was going to remove the plastic pressure strip eventually anyway, I should have removed the felt+plastic strip as a whole, and then carefully separated the felt from the plastic on a flat surface with more room to move.

Testing Substitute materials

I carefully cut out little rectangles of the Zoflex and Velostat material:

I then pried up the end of one of the plastic pressure strip and inserted the sample rectangles under it so that they covered the two carbon contacts beneath. Keys B7 and C8 were to be the test cases. I’m sorry, I don’t have a picture of this configuration, you’ll have to imagine it.

I then tacked the felt strip back in place temporarily and re-installed the two keys; lifted the key bed chassis back into place and re-connected it (remembering the aftertouch subsystem ribbon cable; easy to forget that one).

As a test patch, I initialized a program on the Novation PEAK and set the mod matrix so that aftertouch controlled the pitch of Osc1, bending it down a full octave at “maximum pressure”.

Results:

• The Zoflex key was unresponsive.
• The Velostat key was EXTREMELY sensitive to pressure.

Conclusion:

• Discard the Zoflex and experiment more with the Velostat.

WARNING: Turn off power to the A-80 before attempting to change the resistance of R43. Trust me. The A-80 will go berserk if you don’t.

By testing the change in touch response after each adjustment the value of R43, I could tell that reducing the resistance produced a corresponding decrease in sensitivity (a good thing!) A value of ~10k for R43 appeared to be optimal. Of course this will be subjective, your mileage may vary… I would think a varistor of 27k would probably give finer control.

What you shouldn’t do, and don’t need to know (Fast Forward)

• I used a crude method of tacking the Velostat rectangles in place
• I replaced the plastic pressure strips over the top and tacked them in place
• I used the 50% best original felt strips for the Black keys, flipping them over and using Kaisiking “red backed” double sided tape as adhesive.
• I used the brand new replacement felt strip for the White keys
• I assembled all of the key bed, and installed in the chassis
• I tested the unit.
• The Black keys worked great
• The White keys would not trigger reliably – the new felt + velostat was too thick, preventing the rubber domes from actuating.
• Also the difference in feel between white and black keys was disturbing.
• Removed key bed from chassis, removed all white keys
• Removed felt strip, which took the plastic strip with it because of the super-tacky double-sided tape I used
• Decided to use the remaining original felt strip for the white keys, and re-do the pressure strip “properly” while I was at it.

Converting the pressure strips

You should apply this process to both black and white keys.

Having peeled back and removed the plastic pressure strips, I carefully cleaned the carbon pads with 91% isopropyl alcohol.

In the most-used keys (the central area), the original pressure pads had left white residue on the carbon pads. Use a light pressure and don’t go overboard, because you can remove carbon from the PCB and you don’t want to do that. Just clean them as much as you can, to encourage uniformity in touch response.

I then cleaned both sides of the plastic pressure strip with the isoprop, to remove as much of the residual sticky as possible.

The next step was to apply the double-sided tape to the resistive side – the side that will be laid over the carbon contacts on the PCB.

Using tools to keep use of greasy fingers to a minimum, I peeled the backing from the tape and placed the rectangles of Velostat over the pressure pads:

Next steps:

• Carefully place the pressure strip back on to the PCB, locating it very carefully so that the pressure pads are over the carbon contacts for each key.
• Firmly burnish the strip in place to encourage the adhesive.
• Place a second layer of tape over the top surface of the plastic pressure strip (in hindsight, I could have done this before placing the Velostat rectangles.)
• Peel the backing, and place the original felt strip over the pressure strip.
• Re-install the white keys

And that’s it. Wonderfully responsive, polyphonic aftertouch.

The LCD display on my A-80 has always been a bit dim, but it is still usable. I think the backlight had dimmed over time, although I could still hear the whine of the voltage transformer that supplied it with power.

This noise is a known issue, and inspired by The Midi Maniac’s YouTube video, I ordered a replacement display from Gregor Walbeck E-Pianos in Germany. The part arrived in timely fashion, with very good instructions. Rather than re-create the excellent video, I’ll just add a few supplemental steps.

The standard first step for getting into the A-80 is to remove the screws from the underside in order to release the top panel and allow it to lift up and open. I’ve talked about this process before.

Having removed the 15 screws from the underside, but before opening the lid, there is another step that we need to do.

In order to reach the display sub-board, you will need to remove four screws that retain the metal sub-board chassis plate on which Main-A and Main-B pcb’s are mounted.

If you’re like me, you will have opened up the unit and discovered this plate is solidly attached by screws from the back of the unit:

These screws can be removed from the back side of the lid:

There is still one screw internally holding the plate in place, but it can be easily removed when the lid is open. I don’t have a picture of that, but you can see the MIDI Maniac removing it in his video. He doesn’t mention the four screws at the back, at all. They certainly add some stability to the internal circuit boards, but I can also see how they might have been added in a later production run, maybe.

Anyway – if your unit has these screws in the back, you will need to remove them. In my unit, these were two machine screws (outermost) and two self-tappers (innermost). I don’t know why they are different.

Word of warning: I had great difficulty re-inserting these screws. Aligning the mounting plate, then closing the lid in order to screw them in place was a trial. The threaded holes are in the mounting plate itself, not the thin back plate of the lid. There was no way to partially tighten the screws, then align the mounting plate on the points of the screws. I think if I had rotated the unit so that the lid was upright over the lip of the desk, I might have been able to re-fasten the screws while the lid was open. However, I persevered and eventually got it all tightened up.

Then, disconnect CN3 and CN4 from Main-A board. I needed to disconnect them to create some slack. Now, after unscrewing the single retainer screw in the center of the board, you can carefully tilt the mounting plate towards you to gain access to the display sub-board, nestled into its recess.

There are two connectors to remove from the display pcb: Power, and the ribbon cable. The display unit is retained by four screws, one in each corner. The only problematic one is the lower right, which I had to approach from under the bottom of the main boards’ mounting plate. There was only just enough clearance for an awkward operation. Not ideal, but I didn’t want to disassemble more than I absolutely had to.

The replacement display comes with eight plastic washers. I assumed that, due to the slightly thicker profile of the new unit, that these should be placed on either side of the pcb, so that the board was very slightly raised further out from the plexiglass window, and also protected from the head of each screw.

Okay, MIDI Maniac shows this reasonably well in his video, but in words: I inserted the screws on the right side, with the washers in place, loosely so that I could slide the new display board in from the left (the mounting holes in the PCB are actually slots). Then, using double-sided tape to hold the plastic washers on either side of the PCB, I could rotate the display into place, and then insert the screws on the left side and tighten them all up. (Remember to remove the sticky protection label from the top of the new screen before doing this!)

Then, simply attach the ribbon cable to the board. As per instructions, it does not need the power connector. This can be un-threaded back to the PSU board and curled up and zip-tied out of the way.

Now for testing:

Worked first time. Yay. Now the instructions are very clear about how to remove the two components on the PSU board that are no longer required to deliver power to the display. I snipped them off with a pair of nipper pliers. No More High-pitched whine!

So, either I have to pivot to writing music without D above middle C, or I have to repair my Roland A-80 again. The D4 key stopped responding. After a miserable couple of days procrastinating, I opened her up and took a look.

I’ve written about disassembling the A-80 keybed before, and of course the first thing I did was open that post and refresh my memory. Quick recap for first-time readers:

• The A-80 is HEAVY and most of that is in the keybed itself;
• It uses a rubber dome with two contact switches to trigger a velocity-weighted note event from each key press.

One thing I was sure about: After last time, I wasn’t going to try and lift the entire keyboard off the table, and also I was going to need to have it in a state where I could monitor MIDI output whilst testing key presses.

I pulled the keyboard out and unplugged it, then tilted it onto its back edge (on a soft towel) and removed the necessary 15 screws from the underside.

Right-side up, carefully lifted the lid. At this point I deviated from the previous process – I needed this to be in a playable state whilst examining the inner workings of the keybed. I unscrewed the 12 screws holding the keybed in position in the chassis (shown as II and III in the diagram above – III from inside the chassis, and II from underside. Then I lifted the keybed away from the lip of the chassis and raised it up on two metal blocks (about an inch high) on either side. This was sufficient to be able to remove the white keys whilst leaving all the connectors in place.

The key removal tool made quick work of removing the keys around the problematic “D”:

Not the sharpest knife in the draw, am I. When I saw that “!” in black sharpie on the base plate, I remembered from last time: D4 was the key in which I accidently damaged the rubber dome. I left it unrepaired last time, because it sat correctly, the invisible slit in the side of the dome didn’t appear to affect the key response. (And, indeed, it worked fine for 6 months.) Yet, here we are.

This was a great relief, to know that there was an actual root cause to the failure of D4, and not just something random breaking.

So, what to do? First, I tried repairing the slit (which was substantially larger than I remember) with superglue.

THIS WAS A BAD IDEA.

A) it doesn’t seem to bond the rubber dome together, and B) very great danger of getting glue on the conductive contacts under the dome or on the PCB. NEVER TRY THIS.

At this point, if I had no other recourse, I was prepared to re-purpose the rubber dome from the lowest or highest note, sacrificing it and yielding a functional 87-note keybed.

I had one more thing to try, however: Replacement rubber domes from www.bustedgear.com. I haven’t found any genuine article for the Roland A-80 in stock anywhere, but these replacement parts KCS10 are apparently good for the A-50 and they sure looked near-as-dammit identical. I’d ordered a couple of sets several months ago, on a hunch that I might need them in the future. THE FUTURE IS NOW

Using an exacto blade, I carefully removed the damaged D4 dome. The domes are installed as a strip, held in place by double-sided tape (true!) and the white key domes are subtly different from the black keys. Upon close examination of the replacement, I could see they weren’t an exact match with either black or white key dome, but I think they would be close enough. Anyway, the bad dome had to come out, even if I was to replace it with a dome from elsewhere in the keybed. It was worth trying these KCS10 domes, just to see.

Trimming the replacement dome to fit was finicky but the exacto blade earned its name. The replacement dome is slightly lower (not easy to see from this angle):

I carefully installed the D4 making sure not to dislodge the new dome, just sitting in place with the slightly tacky and very dusty tape remaining on the PCB.

Connect mains power and MIDI out, open Cakewalk with an instance of Pianoteq responding to notes, and HOT DAMN if it didn’t JUST WORK. Perfect? Pretty close. It does seem to respond a little “hotter” in terms of velocity sensitivity, which makes sense if the new dome is slightly lower/closer to the PCB. But you know what? The velocity sensitivity across the whole keybed has some variation in it, and this is DEFINITELY playable. It’s not wrong; it’s just slightly different. Not really noticeable unless I listen carefully.

Let me be more clear: I can forsee a time when I a) experiment with replacing a Black key dome, and if that works okay, then b) replacing the whole 7+octaves. That would give the A-80 a usable and consistent velocity response.

Okay, um, let’s take the key out and try and attach that dome in place a little more firmly. I used two tiny pieces of fresh double-sided tape and I guess it made a slight difference. Probably not a great idea, if one of the strips comes loose, it could work its way up or down to cover the contacts under the dome, and then this key will stop responding again. At least I will know how to fix it.

All keys back in place, keybed restored to original position, all screwed together, and hey we’re good for another take.

I can not remember when I acquired the Roland A-880 MIDI Patch Bay. It certainly wasn’t the first piece of kit I ever bought – that honor goes to a second-hand Roland Jupiter 6 back in 1988. It had some DIN ports – In and Out – on the back for something called MIDI. It was soon followed by an Akai sampling keyboard and synthesizer rack module, which worked very well together when connected with MIDI cables. Also, you could send notes from the Jupiter to the Akai devices over MIDI, so long as you set the rack to listen on MIDI Channel 1 or 2. Shortly after that, we found a Roland MIDI Interface (MPU-401?) for our PC, and started recording MIDI sequences into a copy of Passport Software’s Master Tracks Pro.

Recap: MIDI in a nutshell

So far, so good. We had PC software that allowed us to perform patch librarian tasks using MIDI (called System Exclusive or SYSEX) on many of the devices but it requires bi-directional data transfer between the sound module and the computer, and signals in a single MIDI cable only go one way: You need two cables connecting the In and Out ports. From the computer OUT to the module IN; and also from the module OUT to the computer IN. The computer requests data; the module sends it; the computer sends more data.

MIDI messages are assigned a “channel” between 1 and 16. So if you connect a MIDI cable between two devices, a device listening on channel 1 won’t respond to any messages assigned to channels 2-16. More information here.

This allows more than one device in a MIDI chain. In fact, later keyboards and modules included a third port, a MIDI THRU that would re-transmit incoming MIDI signals to the next device in a chain, allowing layering and multi-timbral setups. Some manufacturers combined the THRU and OUT connectors.

I realize as I write this that it all sounds archaic these days, when we have digital bi-directional comms over a single USB connector, let alone Ethernet and WiFi. But back in the 1990’s, it was like magic, and no-one complained that they needed two cables for this type of two-way communication.

The problem is that the more devices you have, the more un-plugging and re-plugging of MIDI cables is required to manage all the equipment. Some sort of automated patch bay becomes almost required. Enter the Roland A-880 MIDI Patch Bay.

The A-880 is basically a box with 8 inputs; 8 outputs; and it will connect these together any way you like. You can use it ad-hoc by selecting an input (from the top row of eight buttons) and then selecting which of the eight outputs (from the bottom row of buttons) the MIDI messages are echoed on. If you find yourself using the same set of connections over and over, you can save it in one of the 64 possible memory locations for easy recall.

The Studio Equipment

For the purposes of this article I’m using the following devices:

• Windows 10 computer running the Cakewalk by Bandlab DAW
• MIDISport 2×2 USB MIDI interface (ports A and B)
• Roland A-80 Keyboard controller
• Roland SPD-20 Drum Pad controller
• Novation PEAK synthesizer desktop module
• Korg M1 Synthesizer keyboard
• Korg TR-Rack synthesizer rack module
• Roland D-550 synthesizer rack module

All these devices have MIDI In and Out ports for sending and receiving MIDI messages such as notes, clock, and system-exclusive (data dumps and patch edits). I’ve already decided which MIDI channels each device is going to use.

Aside: Cakewalk and MIDI Echo

Cakewalk – and presumably other DAWs – has the ability to mimic the behavior of a THRU port, and echoing the incoming MIDI data from input to output. It records the performance into the active track, but also optionally echoes the notes through the computer’s MIDI output port. This lets me play the Roland A-80 whilst hearing the sound from, say, the Roland D-550.

More on this in the Cakewalk Manual: Controlling MIDI playback – MIDI Echo

Use Case 1 – Playback of a previously recorded MIDI project from the DAW

It’s an old project from back before we had the ability to record Audio tracks in our computer. It has three tracks and I need to send the MIDI out to the Korg M1; the Roland D-550; and the third track was drums and there’s a nice standard kit on the TR-Rack that will do nicely. So I need to connect the MIDI OUT from the computer to the MIDI In on those three modules:

Unfortunately, that arrangement can’t be done as-is because the MIDI cables are point-to-point: one Out port has to go to one In port. Instead, we have to daisy-chain them using the MIDI THRU ports on each unit:

That works – providing you have the THRU ports available.

One down-side of this is latency, in that if your chain has too many hops, then the instrument at the end of the chain can take a noticeable time to respond after you press a note. Also, there’s a potential for signal degradation. If you limit yourself to 2-3 devices in a chain, it’s not a problem, and it works.

Use Case 2 – Recording a performance into a new MIDI track

Now I want to record a MIDI performance on the M1 keyboard into a new track in the project in the computer software. So I need to connect the M1 Out to the computer’s In:

Hang on, the M1 keyboard is great for some types of playing styles, but after some practice runs, I think I really want to use the weighted, 88-keys of my Roland A-80. Just a sec, I need to re-connect:

Okay, enough! I’m sure you get the idea. Let’s move all these connections into the Roland A-880. One advantage is that now, we can feed multiple In ports from a single Out port, reducing the latency and signal degradation (which in practice isn’t a problem, but hey, it’s all good):

Making virtual connections between the ports is easy once you know how: Press a button on the top row, followed by one or more buttons on the bottom row. Then press Scan/Mix or Signal to complete the configuration. So to set it up as shown above:

• Press In-8
• Press Out-4, Out-5, Out-6
• Press In-7
• Press Out-8

Now I can send my performance on the A-80 to the Cakewalk DAW running on my computer; and in turn, Cakewalk sends the MIDI notes from the existing tracks out to my sound modules.

If I decide I’d like to record the next track on the Korg M1, I can merely switch from the A-80 by:

• Press In-4
• Press Out-8 (this “disconnects” the previous connection from In-7)

Now the M1 is the “controller”.

Connecting the rest of the gear

Now we go into the closet and pull out ALL the MIDI cables, and connect all the devices:

Ports 1 and 2 are accessible from the front panel of the A-880, so I tend to reserve these for “temporary” connections (although, my SPD-20 drum pad controller has been out of the closet and connected up for about a year now). Port 1 is handy when I want to integrate my iPad into the studio, or back up patches on the Line6 POD.

Now, it is so easy to lay down a new drum track using the SPD-20 as the controller:

Other features

MIDI Clock is a “pulse” or timing reference transmitted along with other data that can be used to synchronize devices. The A-880 will respect the MIDI Clock on the port nominated as “Control In”. You can set which port (1-8) is the “control” by holding down the corresponding input button during power-on. I use Port 8 as the Control In because the PC/DAW is my timing master.

Use Case 3 – D-550 Editor/Librarian operation

I can use SoundQuest‘s MIDI Quest software to download, edit, and upload patches to the Roland D-550, and this requires that we connect both In and Out to the computer:

This works well – I can request a dump from inside MIDI Quest, and edit the patches, but what if I want to try out a few riffs from my handy keyboard controller? I want to be able to both edit the D-550 patches from the Computer (PC on Port 8) and also play notes on, say, the Korg M1 keyboard (Port 4), and have the D-550 respond.

Normally, MIDI does not allow multiple IN ports to direct to a common OUT port.

This is where the A-880’s Mixing function comes in: Any additional input port can be mixed with the control port. By design, Port 8 is my control port and also used by the DAW/PC. So we can add the M1 keyboard into the configuration using these steps:

• Hold down the Scan/Mix button;
• Press In-4 (the Korg M1);
• Press Out-6 (the Roland D-550);
• Release the Scan/Mix button.

That might seem odd but when you see the configuration graphically, hopefully it will make sense:

You can tell that Port 4 is “mixed” because the LED will flash during the scan cycle.

Memory Management

We have 64 memory locations available in 8 banks of 8 patches. I can’t imagine needing all of them. I divide mine into two categories: Bank 1 is “Controller select”, and Bank 8 is “SysEx Operation”. To make it easy to remember, I use the patch number to indicate the “subject” of the configuration:

• 1:2 SPD-20 is controller (on port 2)
• 1:4 Korg M1 is controller (on port 4)
• 1:7 Roland A-80 is controller (on port 7)
• 8:2 SysEx/Dump for SPD-20 (on port 2)
• 8:4 SysEx/Dump for Korg M1 (on port 4)
• etc

You can change programs on the A-880 by sending it patch change messages on the Control In port, using the Control MIDI Channel. You set this channel by pressing Memory + Write , then one of the 16 input/output buttons. For example, to set a control channel of 12:

• Press MEMORY + WRITE (don’t hold)
• Press OUTPUT 4
• Press SCAN/MIX or SIGNAL to complete.

Final thoughts

The A-880 has remained the heart of my studio since arriving back in the early 1990’s. Keyboards come and go (a moment of silence for the Jupiter 6, alas) but the A-880 remains at the hub, probably the most reliable piece of gear I’ve ever owned.

Other useful links

• https://www.polynominal.com/roland-a-880/index.html

This post is mostly for my own reference, and also to replace and supplement information that used to be hosted at http://soundofmusic.se/ but is no longer available.

My Roland A-80 keyboard has a pretty noisy action, and after the success I had replacing the key felt strips in the Korg M1, I figured I should give the A-80 the same love and care.

According to Gearslutz, the A-80 features a Matsushita SK-688 keybed – it’s an older keybed (but it checks out) – and Syntaur have some replacement parts available, including a felt strip suitable for the keybed “lowers”, where the keys rest when they are not being played. I ordered two units, on a hunch (turns out I was right).

When they arrived, it was time to begin the service operation.

Before you begin

I highly recommend getting a copy of the service manual. I’ve saved you the bother of finding it: here it is. That’s the PDF I use, hosted on our site. (It’s not perfect but it is the best resolution and clearest copy I could find online.) I kept the PDF open on my desktop, and flipped between pages as I worked.

Secondly, you will need a key removal tool. There are instructions in the manual on Page 5 on how to make one using a paper clip, and providing you are able to match the dimensions specified, it actually works.

However, it is awkward to use, and not too robust for intensive use. (I went the extra mile and sacrificed a teaspoon for the cause. More on that later. If you don’t have access to a basic workshop, be assured that the paper clip tool does work.)

Wherever you move the unit to, make sure it is at a comfortable working height. I initially placed it on a “standing desk” but this was really too high. I should have just used a regular-height table. The A-80 weighs a ton. (30 kg?). Most of that weight is concentrated at the front edge (each key is weighted at the tip and that is where most of the weight comes from).

Opening the Lid

The top is hinged at the back edge and flips up like a car bonnet, once you have removed some screws from the bottom of the unit. Page two in the Service Manual has the details but I’ve got a diagram from another post about the A-80 which I’ll re-use here:

You either need to flip the unit on its back, balance it upright on the back edge as you remove the screws. Either way, it’s awkward and risky. (It was at this point I realized the standing desk was probably a bad idea.) Restoring it to the normal position, the lid then swings up for easy access.

If I recall correctly, there’s an earthing wire that will possibly prevent the lid opening to a useful working angle. In my unit, I’ve lengthened the wire so that I don’t have to unscrew one of the lugs, but your unit may be different. Use caution.

Now we’re ready for the next step.

Removing the keybed

If you’re only interested in removing the black keys, you don’t need to remove the keybed from the chassis: Black keys slide out towards the back; White keys towards the front (where there is no room in the assembled unit.

Removing the keybed requires:

• Disconnecting the cables;
• Unscrewing the keybed from the base.

Disconnect the copper shield

It’s attached to the keybed by three screws:

Unplug the “key pressure” ribbon cable

It is easy to unplug the cable from the CN8 connector on the MAIN-A board:
Mark the ribbon with a sharpie so you can re-connect it correctly later (optional). The receptacle clamps down on the ribbon edge and easily releases the cable if you tug gently on the grey section of the connector to open it:

The ribbon cable is retained by a flexible clamp, and in my unit, a strip of tape holding it to the base plate.

Unplug the PCB connectors RA1, RA2, RA3

In my unit I had to snip a cable tie that was grouping all the wires together. Now that I write this, I realize that I forgot to replace it. Oh well, no big deal. RA1, RA2, and RA3 are marked on the PCB.

If necessary, you can use a small screwdriver to loosen the connectors. They are keyed, you can only insert them one way.

Unscrewing the keybed from the chassis

There are 12 screws to remove: 6 from the inside back edge, and 6 from the underside at the front of the chassis. These are indicated as “II” and “III” in Fig.1 above.

Now we can lift the keybed out of the chassis and place it on a clean padded work surface. Take care to protect the ribbon cable – it is still attached, and is fragile.

Now would be a good time to take a vacuum cleaner to the interior of the chassis. I don’t know about you, but my unit was pretty filthy inside under the keys.

Reviewing the keybed

Replacing the felt “lowers” means that I’m going to have to remove all the keys. I took some time to review the keys. Each key has an identifier embossed near the hinge. For White keys, its the Scale note (except for one B key which also says “2-2”, and the first and last keys which are A’ and C’ respectively). The Black keys seem to be a random 3-1, 3-2, 3-3, etc, up to 3-6. I can’t see a correspondence between scale position and number.

The parts list on page 4 of the service manual does not give any hints about these codes. I don’t think it is significant, apart from the obvious non-standard keys at the top and bottom ends of the keybed. However, as I put the removed keys aside, I made sure to line them up in order so that I could replace them exactly the same way. I recommend that you do the same.

Removing the keys

Each key consists of a key Holder that is attached to the base, and the Key itself which hinges on the holder, and depresses when you play a note. Removing a key from the base involves reaching through a hole in the Key and lifting a catch on the Holder to allow the holder to be slid out of the base. White keys slide towards the front, whilst Black keys slide out towards the back.

Page 6 of the Service Manual attempts to describe the process clearly, but in all copies I’ve found on the Internet, there appears to be some text missing.

Essentially, the process is:

• Depress the Key
• Insert the key removal lever and rock it towards you so that the tooth engages the Key Holder latch (it is exposed while the Key is depressed)
• Lift the key removal lever slightly to ensure the lock button at the base of the Key Holder is raised out of the hole in the base
• For White keys, push at the back to slide the Key Holder towards the front.
• For Black keys, push on the front of the key to slide the Key Holder towards the back of the base.
• The Key + Key Holder should then lift away from the base.

Having a look at base with keys removed make this more understandable:

The Key Holders fit into the notches in the base plate. Black keys lock in from the back; White keys lock in from the front. You can see the round hole that the lock button fits into… here’s a view from the back:

The key removal tool is for lifting that button out of the hole, via the tooth latch on the key holder.

There’s nothing like trying it out in practice.

One thing you may encounter is that there is a whole lot of double-sided sticky tape all over the base plate, and the key holders are very firmly held in place. It took some force to dislodge them. Sliding them out while holding the key removal lever in place was tricky.

When I started removing the keys, the holder and key would separate and the spring would fall out. Not a big deal to re-assemble, but it’s best to avoid it if possible. Knowing the mechanics ahead of time might help with this.

With the paper-clip version of the Key Removal Tool, I had difficulty lifting the Key Holder lock. Seeing as I was starting from one end and removing all keys, I could use a small screwdriver from the open side to assist in the release:

However, using a screwdriver has risks. After two decades or so, those rubber domes are fragile. USE CAUTION! DO NOT LET THIS HAPPEN:

That’s the D4 key. So long as I don’t poke it, I can’t see the break in the rubber, and I had to hope that the switch was still functional. If not, I’d find out later.

Things were much easier when I gave up on the paperclip and manufactured my own key removal tool.

The thickness of the “blade” at the business end isn’t specified, but the thinner and more polished it is, the easier it will be able to latch on to the plastic catch inside the key.

Imagine you needed a knife for something, couldn’t find one cause all you found was 10 000 spoons…. it could happen!!! And therefore you couldn’t do whatever it was you needed the knife for, and then the next day it turned out that a spoon would have done.

Ed Byrne

With all the keys removed I debated trying to remove all the old excess double-sided tape, and decided that, maybe it was there for a reason, and left it.

Replacing the key felt

This part was easy. It’s also the part where I realized that it was a good thing I ordered two units of key felt, because it took one unit just for the White keys alone.

This new felt feels a little thicker than the old strip.

With the felt replaced, we can re-insert the keys. No special tool is required for this.

Be warned that the thicker layer of felt on the underside means that there is slightly less room available when maneuvering the key into place. I took my time and tried to protect the rubber domes as much as possible from accidental shear forces as the key holder slid into the slot and locked in place.

Problem #1

A side goal of this whole adventure was to take a close look at C#5 which has always been a little “sticky”. It never quite bounced back as quickly as it should, and very occasionally stuck in the depressed state. Sure enough, when I re-inserted it into the base, the same behavior – actually worse – was observed.

Process of diagnosis:

• I tried swapping the grey plastic guide with one from a known “good” black key position, and observed the same problem.
• I swapped the key itself with a “good” one and, again, observed the sticky bounce-back.
• I removed the guide completely, and the key bounced back freely – nice – but with a lot of unacceptable “slop” from side to side.

I decided that either the guide post itself must be bent (not visually apparent), or the key holder slot slightly out of alignment (I find that hard to believe).

The solution I settled on involved removing the grey plastic guide and shaving the sides down a fraction, then re-lubing with a slight amount of grease. Fortunately this was sufficient and the re-installed C#5 key now returned to the upright position snappily. Success!

Reconnecting and Testing

With the keys restored to position, I lifted the keybed back into the chassis and screwed it in place; Reconnected the plugs and ribbon cable, and copper shield.

Anticipate the worst

• You’re going to need to connect the mains power and a MIDI out cable;
• You’re going to need to test every key on the board, with a sound source that is responsive to velocity;
• You’re going to find out that something isn’t working;
• You’re going to have to go back in to the keybed and try to fix it.

Alternatively, just screw the lid back on and heft the A-80 back into your normal position in the studio, and hope for the best. I chose this second option. I recommend that you suppress your optimism, and assume the worst. Get the A-80 into a place where you can test the MIDI output and still investigate keybed issues.

First good news: I found that the D4 functioned normally. That damaged rubber dome switch isn’t affecting the key response. Phew!

Problem # 2

However, G#4 seemed WAY too sensitive, belting out a velocity close to 127 no matter how gently I pressed the key. Ugh.

There’s nothing for it, but to open the lid and remove that key and examine the rubber dome switch.

Pro Tip: If you are diagnosing a Black key, then you do not need to unscrew and move the keybed from the chassis.

I unscrewed those 12 screws, and moved the keybed back towards the rear of the chassis to get clearance at the front; then raised it up an inch or so on wooden blocks so as to give all keys a clear travel path when depressed.

Then I realized that I didn’t need to do any of that, because I was only interested in one Black key. And they pop out from the back of the keybed, not the front.

I hope you’ve enjoyed this tale from the workshop, and maybe even found some information that helps you out in your projects. Drop me a line if you have questions.

If you’re just here for the free SFZ files, the link to download them is at the end of the post. But if you are interested in the journey I took to get there, keep reading.

Introduction

I’m thinking of including sounds from a Javanese Gamelan in my next project. After some Internet searching, I found a pretty complete set of samples available from Casa da Música released under a generous license. The sample files are available in a single download:

DigitopiaCdM_Virtual_Gamelan.zip   360 MB

Unpacking the ZIP reveals a substantial directory structure:

DigitopiaCdM_Virtual_Gamelan\
    CASA DA MÚSICA's VIRTUAL GAMELAN.pdf
    Gamelao_CdM\*.nkm
    Gamelao_CdM\
        WAV\
            Gamelão da Casa Da Música - Porto, Portugal\
                BONANG\
                DRUMS\
                GAMBANG\
                GENDER\
                GONG\
                KEMPYANG\
                KENONG\
                KETHUK\
                SARON\

The sample files for each instrument are distributed within the subdirectories, along with a set of instrument definitions for NI’s Kontakt Sampler.

Unfortunately I can’t use the .nkm Kontakt instrument definitions because I don’t have the full version of Kontakt. However I do know how to create my own instruments using the SFZ format, which is a standard text file format used by many Cakewalk virtual instruments and other third party sample players like the venerable but lightweight rgcaudio SFZ Player, or Plogue Sforzando.

Reviewing the Library

The library contains samples from three families of instruments: Drums; Gongs; and Keys. The samples are in stereo WAV format, grouped into subdirectories and with a file name prefix to identify the instrument:

Family	Prefix	Instrument	Description
Drums		Kendhang Ageng	Drum, Large
		Ciblon	Drum, Medium
		Ketipung	Drum, Small
Gongs	BB_ _	Bonang Barung	Laid Gong, Medium
	BP_ _	Bonang Penerus	Laid Gong, Small
	K_ _	Kenong	Laid Gong
	Kt_ _	Kethuk	Laid Gong
	Kp_ _	Kempyang	Laid Gong
	GA_	Ageng	Hanging Gong, Large
	GS_	Suwukan	Hanging Gong
	GK_ _	Kempul	Hanging Gong
Keys	GS_ _	Gender Slenthem	Metal Bars, Large
	GB_ _	Gender Barung	Metal Bars, Medium
	GP_ _	Gender Penerus	Metal Bars, Small
	SD_ _	Saron Demung	Thick Metal Bars, Large
	SB_ _	Saron Barung	Thick Metal Bars, Medium
	SP_ _	Saron Peking	Thick Metal Bars, Small
	G_ _	Gambang	Wooden Bars

These samples do vary in quality: most are very good, but many have odd resonances; are too quiet; are excessively long; or have tonal differences that are distracting. I can also hear from recording compression artifacts as the sounds decay into silence. Some even have negative phase correlation.

I could actually modify the sample .WAV files themselves for my own use but my reading of the license tells me that I then would not be able to distribute them. (I could be wrong about that.) However there is still a lot that can be done with the raw samples just by controlling how they are used in an SFZ instrument definition.

An SFZ instrument definition is just a text file, using simple HTML-like tags to define how samples are allocated to a MIDI keyboard; and played in response to a key press. (More information on SFZ available here.)

The Scales

Gamelan instruments are either SLENDRO (5-note scale) or PELOG (7-note scale). The scale intervals and root notes are not standardized between orchestras like Western 12-tone temperaments, but within any given orchestra, there should be consistency among its instruments.

The Pelog scale roughly approximates that of the phrygian mode of the Western major scale (E-E on the white keys of the piano), with the notes EFGBC corresponding to the note positions 12356 in the slendro scale used by most gamelan.

Catherine Schmidt-Jones, Musical Travels for Children

Musically, the 5-note Slendro scale is similar to the Western pentatonic scale, with scale intervals of large, small, small, large, small.

The (pelog) scale “selisir” is the most common; this scale leaves out the fourth and
seventh notes.

Pieter Duimelaar

Back to the Library

For pitched instruments, a file name suffix indicates the scale of the instrument, and a number or letter indicates the scale note and octave:

    Sample file suffix  Scale                    Scale Notes
    ------------------  ----------------------   --------------
    __SLxx              Slendro (5 note scale)   1 2 3   5 6   
    __PLxx              Pelog   (7 note scale)   1 2 3 4 5 6 7 

Scale Notes

The Slendro scale samples in the CDM library would appear to use a root note of C, whilst the Pelog samples start on D.

Approximately mapping sample note to apparent pitch:

                   Slendo Scale           Pelog Scale
  Instrument       1   2   3   5   6      1   2   3   4   5   6   7
  -----------      -------------------    --------------------------
  Bonang           C   D#- F   G+  A+     D-  D#  F-  G   G#  A+  B  
  Kenong           C   D+  F-  G+  A+     D-  D#  F-  *   A-  A+  B
  Kempul           C   D#- F   G   A      D-  D#  F-  *   A-  A+  B
  Gender Slenthem  C   D+  F   G   A+     D   D#  F-  G   G#  A#+ B 
  Gender Barung    C   D#- F-  G+  A+     D-  D#+ E+  *   G#+ A+  B  
  Gender Penerus   C   D+  F-  G+  A+     D   E-  F+  *   G#+ A#  B+  
  Saron            C   D+  F-  G+  A+     D-  D#  F-  G+  G#+ A+  B  
  Gambang          C   D+  F   G+  A+     D   D#  F-  *   G#+ A#- *

* = No sample provided (see “Selisir” scale variant described above).

This assumes that the scale note number in the sample file name is accurate – which seems to be the case.

Assigning Samples to the Keyboard

When mapping the Slendro samples to the conventional piano keyboard, we could start at C. However, musically, the 5-note Slendro scale is similar to the Western Minor Pentatonic scale, and therefore maps quite well to the black notes on the piano keyboard. If we did that, we could then map the Pelog scale notes to the White keys.

In reviewing the samples of each instrument, I found that the Slendro scales aren’t consistent in their interval sizes:

Instrument     Slendro Scale Interval                     Pentatonic Root
----------     --------------------------------------------  ------------
Bonang          [1]long [2]short[3]short[5]long [6]short[1]    [1] C    
Kenong          [1]short[2]short[3]long [5]short[6]long [1]    [6] A+
Kempul          [1]long [2]short[3]short[5]long [6]long [1]    [1] C   
Gender Penerus  [1]long [2]short[3]long [5]short[6]short[1]    [3] F-
Gender Barung   [1]long [2]short[3]long [5]short[6]long?[1]    [3] F- (*)
Gender Slenthem [1]long [2]short[3]long [5]short[6]long?[1]    [3] F- (*)
Saron           [1]long [2]short[3]long [5]short[6]short[1]    [3] F- 
Gambang         [1]long [2]short[3]long [5]short[6]short[1]    [3] F-  

                                               (*) approx, matches Penerus

If we assign the Slendro scale note that corresponds to the Minor Pentatonic root to the Eb key; and assign the Pelog scale notes to the corresponding adjacent White keys, we get:

                     Slendro Scale        Pelog Scale
   Instrument        1  2  3  5  6        1  2  3  4  5  6  7
   ---------------   ----------------     --------------------
   Bonang            Eb Gb Ab Bb Db       E  F  G  A  B  C  D 
   Kenong            Gb Ab Bb Db Eb       G  A  B  -  D  E  F  
   Kempul            Eb Gb Ab Bb Db       E  F  G  -  B  C  D 

   Gender Slenthem   Bb Db Eb Gb Ab       C  D  E  F  G  A  B
   Gender Barung     Bb Db Eb Gb Ab       C  D  E  -  G  A  B
   Gender Penerus    Bb Db Eb Gb Ab       C  D  E  -  G  A  B
   Saron             Bb Db Eb Gb Ab       C  D  E  F  G  A  B  
   Gambang           Bb Db Eb Gb Ab       C  D  E  -  G  A  -   

I admit, I’m probably way over-thinking this.

Pros:

• The “Keys” instruments will share a common scale note : key note mapping (same pitch = same key)
• The Slendro scale notes will be intuitively produced from the Black keys on the keyboard;
• The 12 notes in each octave will uniformly increase in pitch from low to high, making some interesting performance possibilities (trills, note substitutions, cross-scale melodies)

Cons:

• Note 60 (“middle” C) isn’t going to produce a tone pitched at 262 Hz for any instrument, although this is hardly a new concept in orchestral assemblies;
• It’s a shame that Kenong doesn’t map elegantly to Eb, matching the other Gong family instruments.

The SFZ Instrument Definitions

I developed the SFZ instrument definition files using Plogue Sforzando and the SFZ v2 format. However it would be easy enough to convert these back to SFZ v1 if necessary; I didn’t use any features unique to v2 other than the default sample path.

Each definition file uses a <control>default_path= operator to set the base directory to allow the sample files to be located. If it weren’t for those accented characters in the directory name, I’d have located the .SFZ files in the same directory as the .nkm files, the Gamelao_CdM\ folder.

But even just cutting and pasting the subdirectory name can cause problems, as you can see: “Gamela╠âo da Casa Da Mu╠üsica – Porto, Portugal”.

So instead, I’ve assumed the following relative directories:

./*sfz
./WAV/BONANG/*.wav
./WAV/GAMBANG/*.wav
etc...

This means that you’ll have to re-arrange the subdirectories to match, or edit the .sfz files to relatively or explicitly locate the samples where-ever you decide to put them.

I’ve prepared three categories of instrument definitions, indicated by a file name prefix:

• RAW_ uses all available samples assigned to MIDI notes as per the table above. Slendro on the Black keys, Pelog on the White. I used Key Switches to separate the different kinds of sample (scale, mute/unmute, piano/forte) where available, for easy comparison. Feel free to use these instrument definitions in musical projects but really this was just intended for reference and review. I’ve made comments against each sample, where appropriate.
• FIX_ are based on RAW_ but refined. Some sample substitution to omit noisy or tonally distracting samples, but retaining the original charm of the instrument. Hopefully still “organic” sounding. Ideally, this is what I’d use in projects that required the traditional Javanese tuning.
• TET_ are 12-tone Equal Temperament versions, with A4=440 tuning, using cross fades, multi-samples, and other techniques to create instruments that would be used for Western tuning projects.

RAW_drums

In general these are well-recorded samples, L-R balanced, low noise. A collection of “door slams”, “bongo hits”, and “face slaps”. I’ve assigned them to C2 > C3.

RAW_bonang

C1 and D1 are used to switch between the Barung and Penerus voices respectively.

RAW_gongs

Kenong, Kethuk, and Kempyang are arrayed with C1 and D1 switching between Muted and Un-muted (sustained) tones.

Kempul, Ageng and Suwukan are arrayed together with E1 and F1 switching between Piano and Forte voices.

RAW_gender

Slenthem, Barung, and Penerus instruments are available using Key Switches on C1, D1, and E1.

RAW_saron

Demung, Barung, and Peking size instruments are available using the C1, D1, and E1 key switches.

RAW_gambang

No voice variations, just Slendro and Pelog mapped across the Black and White keys, from A2 > G6.

The “FIX” instrument definitions

FIX_bonang

I’ve combined Barung and Penerus into one SFZ instrument, using round-robin alternating for over-lapping tone ranges.

FIX_kenong

Seeing as we have both muted and un-muted (sustaining) tones for Kenong, Kethuk, and Kempyang instruments, it seems sensible to combine these into one instrument definition. We could use key velocity to switch between them, but I don’t think it “works” from a performance point-of-view. I’ve used key switching, with C2 and D2 controlling Muted and Un-muted respectively.

Alternatively, we could replace the Key Switch with the following opcodes in order to play the sustained notes when the Damper Pedal is depressed:

<group>
hicc64=100          // play group when cc64=0   (sustain pedal up)

<group>
locc64=100          // play group when cc64=127 (sustain pedal down)

In practice, I didn’t like how the sustain pedal affected the natural decay of the sustained tones when the key was released, so I’ve left it as key switching. Feel free to experiment.

FIX_kempul

We have loud (forte) and soft (piano) tones for Ageng, Suwukan, and Kempul gong voices, so I combined these into one SFZ instrument, using velocity switching to change to the Forte tones. Some volume matching between samples was used.

I realize that the point in the velocity curve where the switch happens is dependent on the controller’s velocity curve; personal preference; etc, so tweak to taste.

FIX_gender

Tonal differences between the Slenthem, Barung, and Penerus sizes mean that I’ve left them as separate key-switched ranges in this SFZ instrument. C2, D2, and E2 respectively.

I’ve used sample offsets and volume matching to try to even out some of the harsher samples, and used sample substitution in the worst cases. The result is a more uniform instrument, but still with character.

FIX_saron

Because of a similarity of tone between the three sizes, I’ve combined these into a single SFZ instrument, using velocity switching for loud and soft tones; and round-robin for duplicates. I’ve adjusted for volume differences and also substituted some samples in cases where noise was distracting (vibration or rattle).

FIX_gambang

Generally clean samples. The Slendro notes have some rattle but it is a musical sound. Outliers in the Pelog scale have been substituted for. Clicks and initial “dead space” in the samples have been removed by limiting the sample playback regions.

The “TET” instrument definitions

The CDM library samples are used to construct a good-sounding 12-tone Equal Temperament instrument with A4=440 using the Gamelan Instruments’ samples as a source. This could be used in musical projects that would work best with Western tuning.

I’ve allowed more creative leeway in assembling the instruments. In the case of Gender and Saron, I liked the effect of playing all layers at once so I’ve provide a couple of alternative SFZ files that do that.

Definition	Description
TET_bonang.sfz	Laid Gong, Range B3 > F7
TET_kenong.sfz	C2: Laid Gong (muted), Range C4 > E5 D2: Laid Gong (sustain), Range C4 > E5
TET_kempul.sfz	Hanging Gong, Range E2 > C4 (piano/forte on velocity switch)
TET_gender.sfz	C2: Large Metal Bars, Range C3 > C4 C#2: Medium Metal Bars (Slendro), Range C3 > G5 D2: Medium Metal Bars (Pelog), Range G2 > G5 D#2: Small Metal Bars (Slendro), Range G3 > G6 E2: Small Metal Bars (Pelog), Range G3 > G6
TET_gender_ALL.sfz	All layers enabled. Thick! Range C3 > C7
TET_saron.sfz	C2: Thick Metal Bars (Pelog), Range G3 > C7 D2: Thick Metal Bars (Slendro), Range G3 > C7
TET_saron_ALL.sfz	All layers enabled. Thick! Range C3 > C7
TET_gambang.sfz	Wooden Bars, Range G2 > G6

Okay, so where can I get these SFZ definitions?

The SFZ definition files are available here: https://prodigalsounds.com/downloads/CdM_Gamelan_SFZ.zip

Reminder: You will also need to download the Gamelan WAV files referenced by these SFZ definitions, from Casa da Música.