Single I/O GM5 works on iPAD CCK without hub

[Breeze]

I built one of the small PC board GM5 boards with a single MIDI I/O. I think it supports more, but I wanted to build the smallest interface possible.

So I guess the power draw must be very small because plugging it into the iPad's Camera Connector Kit's USB connector works without issues, without additional power via PS or USB Hub. Even with the LED still in use.

FYI...

Edited April 22, 2012 by Breeze

[TK.]

Cool! :)

I had no luck with a no-name (cheapo) camera connector kit, so that I purchased an iRig MIDI meanwhile, which is available for ca. 50 EUR at amazon

Advantage: MIDI IN/OUT/THRU already integrated (no USB MIDI interface required), and an additional socket to power the iPad via USB from an external power source.

Best Regards, Thorsten.

[Breeze]

I had no luck with a no-name (cheapo) camera connector kit, so that I purchased an iRig MIDI meanwhile, which is available for ca. 50 EUR at amazon

Advantage: MIDI IN/OUT/THRU already integrated (no USB MIDI interface required), and an additional socket to power the iPad via USB from an external power source.

Best Regards, Thorsten.

I considered that too, but in the end I'd really like to get a digital audio output out of my iPad so I need an all-in-one solution. So I'm considering the Tascam iU2 which does MIDI. Audio In, SPDIF out and can power the iPad as well. It's a little expensive and it seems to be on the cheap side build wise; I'm waiting to see one locally. I'm also waiting to see if something better comes out. The Line6 Mobile In is another candidate.

In the meantime, I found that using a powered hub, I can use my Apogee MiniMe with the GM5 MIDI concurrently, giving me a good A/D, decent D/A and MIDI. It's too bad only the A/D input goes to the SPDIF... unless I connect the D/A out back into the input.... back to the lab... :shifty:

BTW: if any of you are looking for guitar input circuitry for the Mic in at the headphone input, I found these useful links:

Planet-Z's simple iOS Guitar circuit This is part 2 of 3, but it's the one with the schematic.

What looks like the schematic of an iRig

And if you want to plug whatever preamp into the iOS mic input this one does the trick. Apparently the mic input will only work with the iOS device if you use the 2k7 resistor from mic input to ground.

And finally, the TRRS input jack polarities are T audio Left, R audio Right, R common ground, S Mic input. If you can find and modify TRRS cables, great. I got my plugs at Digikey (CP-35401SP-ND I know it says "stereo" but it is TRRS); However, it turns out the bottom sleeve connector is also the ground lug, which is a bit awkward. TRRS is hard to find; I haven't found any TRRS jacks (if anyone knows...)

Remember though, that the mic input on iOS devices has a low cut below 100 Hz or so, so it's not the best way to get audio into your iDevice. But it's not too bad for guitar, a typically mid-heavy instrument particularly in its electric form, and can be compensated for in DSP.

Edited April 23, 2012 by Breeze