GM5: Least-cost USB-MIDI Interface Chip for 4.50 EUR

[Kartoshka]

Could wick remove too much solder so it left pin unsoldered to the pad?

don't think so, it heats and melts solder well on pads under all the pins too... am i wrong?

[Sasha]

Your wick left more solder on pins than mine. Mine looks like factory soldered... almost no solder visible.  :-\ I applied enough solder before using wick but it seamed thirsty for solder. I think everything is right, but as I`m not experienced with SMT I`m bit suspicious. Using magnifier glass to inspect it didn`t help me much.

[Kartoshka]

sure, but try the multimeter test.

[madox]

Your wick left more solder on pins than mine. Mine looks like factory soldered... almost no solder visible.  :-\ I applied enough solder before using wick but it seamed thirsty for solder. I think everything is right, but as I`m not experienced with SMT I`m bit suspicious. Using magnifier glass to inspect it didn`t help me much.

I expect there would often be enough solder left after use of the wick. I still wouldn't recommend using wick for SMT, particularly if not experienced. As mentioned before, it can grab pads, and damage PCBs. At least try using flux, and gently drag soldering with a rounded tip.

Remember to tag down the corners of the chip with solder first. Some pick and place machines actually use an adhesive to hold the devices in place, while wave or oven soldering. You could try this, but not all glues would be appropriate. Certainly some would fume in an unpleasant way.

[strophlex]

Is there any use with flux when soldering the pins individually? What does it do exactly? I am a bit confused with the flux business... It comes in spray, paste, pen, you name it form too... Is the sodering iron tip shape critical when drag soldering?

[madox]

Is there any use with flux when soldering the pins individually? What does it do exactly? I am a bit confused with the flux business... It comes in spray, paste, pen, you name it form too... Is the sodering iron tip shape critical when drag soldering?

Hi,

The details have been discussed previously. Have you watched the instructional video that was posted in this forum a couple of times? I think it is a really good place to start.

Flux reduces the surface tension of the wet (molten) solder, and enables it to flow a lot more easily. Basically, using flux allows the surface tension of the solder to snap into shape around the hot exposed metal surface, and bead away from the solder mask and other materials.

Most flux is basically doing the same thing, as described above, and it probably won't matter which type you use. Some solder additive fluxes are really operating on the viscosity of the solder, rather than the surface tension, and don't really achieve the same result. I have used gel/paste a lot, which is fine, but not cheap. Liquid flux is cheaper, and is used to good effect in the video.

Most fluxes will require you to clean your PCB with something like isopropyl alcohol. Do the cleaning before fitting any components that may be affected by or retain moisture, such as potentiometers or switches. These things rarely require flux.

Using a rounded tip is important, as a small, sharp tip can tear the materials on the PCB when it is dragged accross (particularly when working in a hurry). Using a large, rounded tip carries a more appropriate amount of solder, and easily drags the wet solder bead accross the contacts. The instructional video recommends using a fillet tip, as the groove will cup the solder. I haven't tried that kind of tip, but it makes sense, and sure appears to work well.

You can still solder pin by pin, with a fine tip iron, if you prefer. It requires more time, imparts more heat to the components and PCB, requires better control of the solder quantity, requires greater manual dexterity, and is more prone to faults. Keep in mind that very fine tracks/pads for some SMD devices, can burn or tear away from the PCB much more easily than what is usually used for through hole designs.

Hope that helps. It would probably be worth practicing on an old discarded PCB, if you can.

-edit: Flux is still helpful when soldering pins individually, though is not as critical as when drag soldering, provided that your tip and solder remain on the one pair of pin and pad. Working this way definitely is possible, though I think not the easiest choice.

[Sasha]

I just soldered missing parts and tested my module, and despite my fears everything worked instantly. Just to mention one more time in hope it will give some courage to the people with no SMT skills... I haven`t got any experiences with SMT except recently soldered the MBFM, but pitch was much wider on OPLs. This is my first SMT with such a small pitch. I didn`t wanted to buy any expensive flux as I wouldn`t use it much. Normal soldering, 1mm soldering wire and wick is really enough to do it right. ;) Now I feel ready for some of those advanced, and maybe faster techniques.

So, who is next to design some SMT PCB?  ;D

[TK.]

So, as I get, it could be configured to show the custom name of the synth, or controller instead of generic USB audio device?

Yes, the EEPROM allows you to assign a different vendor/product ID (VID/PID) + vendor/product names to the device, but unfortunately there is a bug which prevents you from declaring more than 3 IO ports once EEPROM is selected to fetch the descriptors (J1/J2/J3 open)

Details are described in the mbhp_usb_gm5_eeprom application, which can be used to program the EEPROM via MBHP_CORE module.

In addition, the GM5 driver allows you to define different IO port names. If different port names should be assigned to different interfaces, you have to use EEPROMs to assign different VID/PIDs, so that Windows is able to differ between the devices

It sounds cool. Are the port names Thorsten pictured also stored in EEPROM?

I already requested this to Ploytec

Currently IO port names are not stored in EEPROM, but this could be possible in future.

Instead, port names have to be defined in a .ini file, which can be edited with a common text editor.

Please excuse my ignorance on this but are you routing the inputs to different outputs (and vice versa) there? I didn't know this was possible with this thing!

I used the port routing window of MIDI-Ox to demonstrate the possibilities (and the advantage when using IO port names). Probably no other commercial MIDI interface allows you to do change the port names yet - although it is so desirable :)

Best Regards, Thorsten.

[Sebo]

HI:

I choose the shipping via Switzerand, but I didn't recived any PM or PayPal invoice from Screaming_Rabbit yet.

Are the invoices alredy sent?

Thank you

[Smithy]

well i did it individually each one and it gone pretty well; but to ensure it i passed with desoldering wick and removed anything i didn't like.

i used very thin (hmm.. 0.1mm i think? have to check it out later at home) solder and a magnifying glass.

Sorry i just coudnt resist.  :-[

I'm in a strange mood

[strophlex]

HI:

I choose the shipping via Switzerand, but I didn't recived any PM or PayPal invoice from Screaming_Rabbit yet.

Are the invoices alredy sent?

Thank you

I didn't receive it either. Patience is bliss  ;)

[strophlex]

The details have been discussed previously. Have you watched the instructional video that was posted in this forum a couple of times? I think it is a really good place to start.

I have followed this thread from the very beginning and watched the videos, however there were still some questions. Thanks for the answers.

Another one: How big should the tip of the soldering iron be when drag soldering?

[Screaming_Rabbit]

HI:

I choose the shipping via Switzerand, but I didn't recived any PM or PayPal invoice from Screaming_Rabbit yet.

Are the invoices alredy sent?

Thank you

The stuff is packed but the invoices are not out yet... this will happen tonight.

Different than said: You will not get a PM, but directly a PP-Invoice.

Patience is bliss  ;)

... I couldn't have said it better  ;D

Greets, Roger

[MTE]

Hi

based on the http://www.ucapps.de/mbhp/mbhp_usb_gm5_4io_board.pdf ive created a eagle board/shematic.

The ports are arranged like on Midipatchbays  IN 1-5 ... OUT 1-5 (Backview)

Enjoy the attachments....suggestions for enhancing are more than welcome :)

[Kartoshka]

if making a bulk, i'm in.

Other way i see you used second type of midi ports; and as i discovered recently, there exist (at least) 2 types of those connectors: they are distinguished by distance between front legs.. you applied the shorter distance, and TK - broader ones.

[Sebo]

Hi MTE:

Nice idea of doing an I/O board. Can you share the Eagle files?

Thanks

[sineSurfer]

would it be possible this:

GM5 + GM5 -> only one USB connection to the computer?

[cimo]

would it be possible this:

GM5 + GM5 -> only one USB connection to the computer?

what about a 10$ usb hub?

[MTE]

Hi

@ Kartoshka ...thnx, fixed.

@ Sebo ... Ill share when its finished ;)

@ sineSurfer ... good question, Im also interested in this. Maybe 4x GM5`s can be connected to 1 USB ??  = GigaMidiPatchbay :D

@ cimo ... also a good solution ;)

[SLP]

@ sineSurfer ... good question, Im also interested in this. Maybe 4x GM5`s can be connected to 1 USB ??  = GigaMidiPatchbay :D

that's what I had planned before I started worrying about latencies.

I think I'll just buy a 20€ USB-PCI-card

[monokinetic]

Hi,

I noticed in the thread that the remaining GM5 chips will be sold tonight. I would like to ask:

are there many spares?

If yes, what do I need to do to have a chance of buying one of these?

Thanks in advance

Dave mK

[TK.]

There are currently exactly 30 spare GM5 chips + PCBs

Since so many additional people added their name to the request list in the last weeks, I'm planning to sell the remaining chips and PCBs only bundled in a Duopack (2 GM5, 2 PCB). I think that this is a fair "finish" for the first bulk :)

This also simplifies the calculation of costs:

2 GM5 2 PCBs, VAT, no PayPal, shipping within Germany: 16,78 EUR

2 GM5 2 PCBs, VAT, PayPal Fee, shipping within Europe: 18,78 EUR

2 GM5 2 PCBs, VAT, PayPal Fee, shipping outside Europe: 20,78 EUR

Everybody who is in the request list will get a PM this evening 20:00 in the UTC+1 zone.

The first 15 guys will get a confirmation

Your response should contain:

- your name

- your postal address

- (outside germany) email address of your paypal account

To answer your question: add your name to the request list

Best Regards, Thorsten.

[TK.]

Sold Out!

The second bulk order will probably be started end of this year (if there are enough requests)

I cleared the GM5 request list, please enter your name again if you are still interested.

If you don't remember the ordered quantity, just have a look into the history (-> "Old Revisions" button)

Best Regards, Thorsten.

[Pascal]

Is it possible to give everey IO one Status-LED?

[nILS]

Teaser: I got bored (like MTE obviously) and made diy-etchable layouts for the addon board in 5 different sizes. I'll upload the Eagle files, BOMs and .pdfs when I get back home :-)