Hi there
Here my experience building the MegaDrum. I’ll update this thread as I move along.
I’m an architect in the field of cityplanning, so fair to say the wonderous world of solding to me is out of scale by approx. 1:700.000. All thou I’m not all thumbs, you should NOT view my project as a how-to. I have applied weird solutions and I’m publishing partly to offer my experiences and partly to let more skilled people point out the flaws for you to avoid.
I believe you can generally judge a craftman by the level of organization in his workshop. Go ahead and judge my skills, two hours into the battle.
I bought a rubber pad MPS-400 set (Millenium) last year, got fed up with the sloppy bounce and replaced the pads with Millenium mesh drums. I primarily use it as a miditrigger with BFD2. Now it's time to expand the set with a few of cymbals and a percussion section.
A huge thanks Dmitri and Synthex for offering a mindblowing alternative to the TMI-6 or Alesis/IO.
The box
My component supplier presented me with a mountain of small ugly boxes in weird proportions. I’m thinking, since there’s a chance I'll spectacularly crash ‘n burn with this project, it should at least not be ugly to the insult.
Thank you IKEA for the well-proportioned low-budget plywood drawers.
I glued on the bottom from a small drawer as reinforcement and division.
Please note the sides are higher than the bottom. That feature is crucial. This side is btw the top of the finished module.
A thick sidepanel from the drawer system is used as bottom of the module. A fitting suitable for drumrack mounting is added. Note the white furniture pads used as shock absorbation, between fitting and module. Prolly worthless placebo, hehe.
I recommend playing with the layout and taking future expansion into account. Make it bigger than needed, both inside and outside.
After drilling the holes, I added a metal folio to smooth the surface and to give the texture of a flightcase. To get sharp corners with the folio you have to trace a tiny groove on the topside of the folio. Don't apply pressure and cut through! Just use the weight of you hand do the job.
Use the Iron on low heat (and no steam! soz) to smooth and activate the folio's glue. Use a towel between the folio and the Iron or you'll sleep alone on the couch for a while.
This tool or a big drill can be used to re-emerge the holes without shreddering the folio. Don't drill after the folio is applied.
Some more IKEA budget stuff to canibalize. Cardboard drawers offers the flightcase stiled corner protection. Also, the thin metal rim can be used around square holes like the LCD and others, to hide the sawing marks.
Drilling square holes is not one of my strong points...
My finished cockpit with the MD and mixer interface close together. All plugs on the top and no cords, switches and the like on the sides or the back. I've made room for a 17 jack expansion.
The mixer fits like a hand in a glove and the MD can be mounted at a tilted angle without the mixer sliding off.
This is why I needed the elevated rim on the top of the box.
A clean front with just the keys, the LCD and the LED. The LCD was very dim using the 470 resistor, so I replaced it with the spare 100 after the picture was taken and it nice and clear now.
This is the drumrack mount with a small drawer underneigh with a side removed as a cable collector.
Jack inputs
I ordered the v2.8 kit but I had unforseen trouble getting the stuff for jack input PCB's in Copenhagen. This is my sad collection of sockets. 3 different kind of legs to get the magic number 17. The left socket takes a hammer to fit in a printboard, I reckon. So I went the PCB-free jack input road.
On the backside, chaining the pins to be grounded.
This is the Hi-hat jumper part and my first micro solding! *Runs a victory lap while the crowd pounder upon the origin of silver elephant droppings on the board*. I better get some more practice before the real solding begins.
Oh look, the Brooklynn bridge in a warped 60-ies acid trip configuration. Btw the picture does not show the finished Hi-hat jumper part. Don't use for complete reference.
Marking the cable in five and tens makes counting so much easier... and count, recount and count again you will.
While solding, the wires are pulled in the right direction. Redirecting solded wires can't be good.
The Hi-hat mini board is partly hidden under the 40-pin cable. The two blue rings are gathering the grounded wires. Input jacks all done... climb a ladder and look south for the postman to arrive with the v2.8 kit.
Oh, important still in cost-efficient projects... use child labour for time consuming fault finding
The Board
Praticing solding/resolding on an old car stereo
I found it useful to line up the components on a color print of Synthex's board to minimize the risk of mistakes.
Cool service from Synthex provided a few spare parts. Thanks!
Carefully checking the solding for shorts or bad solding. I made a short between pin 39 and 40 and spent 20 mins trying to clear the gap... only to realize 39 and 40 are both ground and connected by design.
Free solding advice: Don't sold after 3:30 am
POLARITY! Well, I wasn't aware any of the components had polarity (note the negative symbol on the side), untill I had already solded 3 of these 'cooling towers'. By blind luck they were all correctly solded and I celebrate that by solding the last 'tower' the wrong way...
2nd free solding advice: Don't sold till after 6:00 am
Everything is mounted on the sides or the top, so the MD can be taken clean off the mount without removing internal wires. Plenty of room for a 2nd board, foot switch pcb, hot coffee tubing, ATM outlet, WifeGain<0, or what ever expansion the geniuses throw at the hungry pack in the future.
NB. The 40-pin cable for inputs and the 16-pin cable for the LCD is not connected to the board in the picture, for a better view
Close-up of my inverted metal casing. The lower fitting for the board is glued to the box since it'll be upside down.
Troubleshooting
This is by no mean a complete troubleshooting. This is merely what I did wrong and how it was solved. Read Dmitri's documentation! Read Synthex's manual! Search the board! Be patient and don't jump to conclusion thinking you know what comes next when the guru's provide their step-by-step solutions/testing procedures. I can garranty, you hold 97.8% of the answer and Dmitri, Synthex and others can only provide the missing link, so pay attention to stupid details.
Jack problem
I was missing signal from 6 jacks. Problem and solution is described in this thread
Polarity of external power.
Be aware of the polarity. There's no standard for polarity of transformers. Some has + on the tip, others on the ring. I had to reverse mine. Also spend a few extra $ on the transformer. Cheap ones will send a high impac jolt down the line if/WHEN they die.
Inserting the ATmega chip
Wait till you're done checking for shorts and breaks. It could save you the chip.
Take great care inserting it... it's no pretty sight having a fully inserted chip with , say leg #23 sticking out!?
Configuration
In a marathon this would be hitting the 30-kilometer-wall. All hardware is done, you grab for the sticks and set up the essentials like midi note number and such. And hmmmmm... retriggering, xtalk, inconsisstent output level and what have you. Will it ever work?. Thing is, you need to rethink this. Hardware done is not the end. It's the halfway point. Plug 'n play is simplicity but it's also robbed of any form of flexibillty.
So the abyss you're stirring into right now, is actually a very good thing. It's your garranty there's a combination for your weird mixture of Roland, trash cans and coffee lids. Finding it should take you throu Dmitri's MD configuration and search the forum!
I'll offer a few of the post I found particularly helpful. It's a long read, but by far the shortest road:
Problem with dual piezo management and hihat controller
My problems' thread...
3 zone cymbal support, Yamaha style. How many of you need it
You need to scroll down in some of them.
I'm by the way, still riding the abyss. This is my snare, doing steady 5-inch velocity strokes. As you can see the output values are all over the place from 1 to 69, but xtalk and retrigger is gone and there are tonnes of options untouched... "To infinity and beyond!"
I may update this thread with my findings doing the configuration.
