newbie greetings

[lilakmonoke]

hi all im an electronic musician from berlin and really like the sound of the opl3. the midibox community is amazing!

 

i cant find any sammichFM kits/builds so now im considering building a midibox fm instead. i think i can handle the soldering except for the tiny feet of the opl3 chips. because of that i would rather buy/trade a complete build but i will also try to build myself. where do i start?

 

cheers!

 

florian

[Shuriken]

You can buy the pcb at:

• SmashTV
• Mikes Midishop

For parts you can try reichelt, musikding, banzaimusic.

 

The only tricky part is the OPL3 chipset. You can try on ebay. Maybe someone has a trusted source?

[lilakmonoke]

thanks! there is lots of chinese opl3s on ebay.de ... are these genuine or am i being ripped off?

Edited March 29, 2014 by lilakmonoke

[Sauraen]

Hi lilakmonoke!

 

In my experience it's not that hard to solder the OPL3 and YAC512s--it's more time-consuming than soldering through-hole stuff, but not really harder. First melt a bit of solder onto each of the pads without the IC there. Then, holding the chip in place on the board with one hand and the iron with the other, push the leg into the solder with the iron, melting the solder. Do this for the two diagonally opposite corner legs first, and make sure the chip is aligned properly so all the legs are right on top of their pads. Once it looks good, do the other two diagonal corners and check again for alignment. Finally push each leg down into the solder, waiting about 20 seconds every couple legs to let the chip cool down again. If a connection doesn't "look" good (you can sort of see with a magnifying glass if the solder has flowed onto the leg), add a bit more solder and see if that does the trick. Finally use a multimeter in continuity test mode to make sure there's no connection between any adjacent legs. If you want to be really thorough, follow each trace and do a continuity test between the OPL3 leg and wherever the trace connects to (obviously these should all show a connection).

 

As far as where to get them from off ebay, I bought two YMF262s and four YAC512s from ebay seller smallpartsbigdifference (http://www.ebay.com/...tsbigdifference) for my build. They combined the shipping on the two orders (for a total price, including shipping, of $15) and all six chips work. They arrived about a week after ordering them, which is pretty good for Asia -> USA. (To be clear, you only need one OPL3 and two YAC512s.)

[lilakmonoke]

thanks for all the info! ill contact the seller see what he says. buying the opl3 from china seems a bit crazy to me when you can desolder them from a soundcard here. desoldering  should be easier than soldering, no? i just have some bad experiences with the tiny legs of smd parts but i guess the opl3 is a lot bigger.

 

so just to doubecheck: for the most basic midibox i only need

1) core module and parts

2) opl3 module and parts

3) bank stick

which i can all get from mikes store

 

+ 2x powersupply whats a simple solution for that?

 

thats it?

 

thanks again for the great support!

midibox rocks!

 

thats i

[Sauraen]

I desoldered one OPL3 and YAC512, and it was more difficult than soldering them; in fact I don't know of a single electronics application where desoldering is easier than soldering (when you want to not destroy the part, of course!). But if you are really uncomfortable with buying from overseas, and you can get a soundcard that cheap that has them, go right ahead. The two tricks to desoldering are: 1) start by adding some extra solder to each leg, and then 2) thread a very fine wire under all the legs so when you melt the leg on the end, you can pull the wire forward and it will come through and separate the leg from the board.

 

For banksticks, I would recommend you build the module on veroboard (prototyping board) so it is easy to add more ICs if you start running out of space. IMHO you should start with 4 or all 8, it's not worth bothering for just one.

 

For the power supplies, you have two options. In either case you will need a 7-10VAC wall transformer, connected to J1 of the core module, to supply +5V. But you also need to power the OPL3 module. The standard way is to use a +/-12VDC bipolar power supply like this one from MFOS . But if you're comfortable with a little modding, you can modify the OPL3 board to be able to run off that same +5V supply, powering it from the regulated +5V output from the core module. Here's the and the resulting Wiki article. I would not recommend the latter if you're not familiar with electronics, though; it's not hard to construct, but it's a relatively new addition.

 

That's all if you only want to control your MIDIbox FM from your computer. Adding the screen is as easy as plugging it in, and you can always build and add a control surface later (obviously more work).

Edited April 1, 2014 by Sauraen

[lilakmonoke]

hi sauraen ... thanks for a the details. i think ill stick with the standard power supply, maybe there is a commercial bipolar 12vdc power supply? i think i can hande the rest and if im stuck i can always post here for help. great forum! ... btw. somebody should design a real time fm synth with a high quality yamaha fm chip like in the sy77. i know there is the preenfm but thats dsp. fm is such a good synthesis but all the 80s synths cannot be edited in real time. cheers!

Edited April 4, 2014 by lilakmonoke

[lilakmonoke]

so just want to say that im finally joining the global midiboxfm revolution and starting the build. ;-) meanwhile ive been programming something similar in pure data just to see what i can do with it musically.

 

also im in the market for a set of opl3/yac512 chips, if somebody want to get rid of some let me know ... and ill be pestering you if i get stuck in the build, apologies in advance!

 

best regards, lilak.

Edited June 19, 2014 by lilakmonoke