ODAC - general and technical discussions

[DoktorSteve]

It should be no problem to use 5m phono cables. The output of the DAC is designed to drive 4700pF but the ODAC has some extra series resistance and 2200pF in the output filter. 500-1000 pF of cable capacitance should not make any difference to the sound and might even make it smoother.

[blackroseblade]

Hi guys, first post here, complete newbie to DIY in general.

I was wondering, is it possible to get the ODAC PCB board fabricated? I live in a part of the world where quality audio is something no one has even heard of yet and I want to start off by introducing people to the ODAC and O2. While the O2 amp can be DIY'd, the ODAC can't and I was hoping there's a solution to this. The US$99 preassembled boards are too expensive regionally, and there are no PCB schematics that you can use to fabricate the boards with.

Can anyone advise me on what to do? If I cannot get the schematics, then some OEM solutions or bulk sales would be nice. George if you're reading this, would love some guidance here.

[GeorgeBoudreau]

Originally Posted by blackroseblade

Hi guys, first post here, complete newbie to DIY in general.

I was wondering, is it possible to get the ODAC PCB board fabricated? I live in a part of the world where quality audio is something no one has even heard of yet and I want to start off by introducing people to the ODAC and O2. While the O2 amp can be DIY'd, the ODAC can't and I was hoping there's a solution to this. The US$99 preassembled boards are too expensive regionally, and there are no PCB schematics that you can use to fabricate the boards with.

Can anyone advise me on what to do? If I cannot get the schematics, then some OEM solutions or bulk sales would be nice. George if you're reading this, would love some guidance here.

There are some obstacles to producing your own version of the ODAC and the main one is access to the Tenor USB audio engine. The supplier does not deal with individuals and businesses need to sign a NDA (non-disclosure agreement) to have access to the chips and data sheets.

I have made the schematics available for those who wish to hack their own ODAC but they are not to be used commercially to make clones. To be called an ODAC it must use the layout NwAvGuy and I created *and* the component selection.

It you wish to purchase a quantity of the ODAC you can contact me and we may be able to work something out.

FYI: I have no more stock and will not be manufacturing any more until January of 2013 or later. As far as I know the distributors are still selling ODAC cards at a steady clip.

Regards,
George Boudreau

[blackroseblade]

That is disappointing... Inbox'd with details of what I'm looking for, please respond at your convenience.

[fraggler]

Can anyone identify what I fried? I think the PSU to speaker amp is improperly grounded or something. This happened within seconds of turning on my amp that was connected to my ODAC. The part on the schematic is FB102. Wanted to see if I could replace the part and revive the ODAC.

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[JZatopa]

Originally Posted by Rullknufs

Dear Stefan, you have a big fault in your guide on how to connect the O2 to the ODAC.
Components

In the last picture at page three you have shown that the black wires go to the upper holes and the white to the lower ones. This is reversed and if you do it like the way in the guide you'll en up with mono sound because so have I.

Looking at this picture here

It show the right way of doing it. If you want I can supply you with a new picture for your guide if you're not okay with "stealing" it from NwAvGuy's blog.

I have somehow blown out my odac. It looks like the part labeled fb102 has burnt out. Could someone tell me what this piece is?

Fraggler did you find a fix?

[agdr]

Originally Posted by DJNUBZ

I have somehow blown out my odac. It looks like the part labeled fb102 has burnt out. Could someone tell me what this piece is?

That looks like either a chip fuse, or more likely chip fusible resistor, on the #5 ground pin coming from the USB port, according to the schematic on George's site. You most likely had a ground loop going on between your computer and the ground of whatever was plugged into the audio out jack or connectors. Try measuring ac and dc voltage between pin 5 of your PC usb connector and the audio ground.

Should be easy enough to replace that chip fuse with the help of some de-solder braid if George can supply the part number.

[agdr]

...another thought - if the ODAC is being used in an O2, then the O2's AC transformer may have excessive leakage between the secondary and primary windings. Since one end of the secondary is ground in the O2, that could complete a power line short through FB102 if the PC being used for USB happens to be 3rd wire grounded.

[GeorgeBoudreau]

Originally Posted by agdr

That looks like either a chip fuse, or more likely chip fusible resistor, on the #5 ground pin coming from the USB port, according to the schematic on George's site. You most likely had a ground loop going on between your computer and the ground of whatever was plugged into the audio out jack or connectors. Try measuring ac and dc voltage between pin 5 of your PC usb connector and the audio ground.

Should be easy enough to replace that chip fuse with the help of some de-solder braid if George can supply the part number.

FB102 is a ferrite bead -Digikey number 240-2399-1-ND
If you smoked the ferrite bead there is a 99% chance you have taken a lot more.

[agdr]

Originally Posted by GeorgeBoudreau

FB102 is a ferrite bead -Digikey number 240-2399-1-ND
If you smoked the ferrite bead there is a 99% chance you have taken a lot more.

May be worth ordering some 0.5A pico fuses too, digikey F5521CT-ND, and tack-solder one over the old bead after the ground loop is believed to be cleared to see if the ODAC is still with the living.