power O2 from USB +5v mod
I've just made a portable mod to power O2 from USB +5v .
DC-DC Photo Gallery by objective3 at pbase.com
Using MEA1D0512DC 9$ 5V to +-12V bipolar DC-DC converter with low noise LC filter 47uH + 1uF on each channel.
This 1W DC-DC converter is able to supply power to O2 from ODAC mini USB line so both work simultaneously from USB power only.
There two options
1) put DC-DC PCB inside 9V battery case and use battery connectors. In this case to use it with battery you need you need to remove DC-DC
2) insert is as a PCB addon as shown at the second half of slides. In this case you can use rechargeable battary and even charge them with DC-DC power (1W = 42mA at +12V and 42mA at -12V). With D-150 250 Ohm Headphones Amp consumes 20-25 mA so you have spare 20 mA to charge battery even while listening.
how to move ODAC from batteries space see ODAC + O2 combo portable mod Photo Gallery by objective3 at pbase.com
I've just made a portable mod to power O2 from USB +5v .
DC-DC Photo Gallery by objective3 at pbase.com
Using MEA1D0512DC 9$ 5V to +-12V bipolar DC-DC converter with low noise LC filter 47uH + 1uF on each channel.
This 1W DC-DC converter is able to supply power to O2 from ODAC mini USB line so both work simultaneously from USB power only.
There two options
1) put DC-DC PCB inside 9V battery case and use battery connectors. In this case to use it with battery you need you need to remove DC-DC
2) insert is as a PCB addon as shown at the second half of slides. In this case you can use rechargeable battary and even charge them with DC-DC power (1W = 42mA at +12V and 42mA at -12V). With D-150 250 Ohm Headphones Amp consumes 20-25 mA so you have spare 20 mA to charge battery even while listening.
how to move ODAC from batteries space see ODAC + O2 combo portable mod Photo Gallery by objective3 at pbase.com
ODAC + O2 combo portable mod
As currently there are plenty of mobile phones/tablets
xda-developers - View Single Post - [Q] USB sound card on Android? and Apple devices supporting external DAC output it makes sense to issue a version of ODAC + O2 portable combo that can work from 9-8.4V batteries as original O2 design. I just did this mod using JDS Labs combo. The only additional effort is drilling one hole in O2 PCB (on unused spot) and moving USB hole on the back plate. Please see attachments. I think it will be useful for current and future ODAC + O2 combo users as well opens combo to new use cases.
so here it is ODAC + O2 combo portable mod Photo Gallery by objective3 at pbase.com
As currently there are plenty of mobile phones/tablets
xda-developers - View Single Post - [Q] USB sound card on Android? and Apple devices supporting external DAC output it makes sense to issue a version of ODAC + O2 portable combo that can work from 9-8.4V batteries as original O2 design. I just did this mod using JDS Labs combo. The only additional effort is drilling one hole in O2 PCB (on unused spot) and moving USB hole on the back plate. Please see attachments. I think it will be useful for current and future ODAC + O2 combo users as well opens combo to new use cases.
so here it is ODAC + O2 combo portable mod Photo Gallery by objective3 at pbase.com
Need help - I built a completely new O2 board ground up instead of de-bugging my old board which apparently developed a issue with Q2. The new board works perfect with input from various sources except for ODAC !! My ODAC has an output jack soldered and I checked that it works fine. But when I connect the wires ODAC + O2 I hear nothing on the phones 
. I triple checked the connections and they look OK visually as well as on the the DMM, any clues ? I did not cut the traces on O2 as I intend to use the input jack. I have routed the wires through the empty POT holes on O2.
. I triple checked the connections and they look OK visually as well as on the the DMM, any clues ? I did not cut the traces on O2 as I intend to use the input jack. I have routed the wires through the empty POT holes on O2.This is seriously exciting. The PSU is a brick. Since I would be looking to mostly use the O2+Odac with my laptop this is a marvellous development.
I would like to implement this myself. However, not knowing much about electronics and seeing the response of RS and others to suggestions generally being negative (or at least suggesting significant changes) I would love to see some comments from the other experts here. Since there has been a notable lack of response to this, perhaps it needs a new thread?
Hi, as digitfan pointed out, as long as the traces are not cut your input signal from the ODAC will be routed directly to ground on the O2. Your input socket will work normally as well after cutting the traces, so no worries.
Stefan
I made a build log when I built my O2, here is a link if you would like to see it -
http://www.diyaudio.com/forums/headphone-systems/217086-building-o2-headphone-amp.html#post3110012
Thanks!
http://www.diyaudio.com/forums/headphone-systems/217086-building-o2-headphone-amp.html#post3110012
Thanks!
....apart from the ones with camera shake. Tsk tsk.
If you have similar photos of the build without camera shake, I will be happy to substitute those in for the offending images.
Unusually good pics.
....apart from the ones with camera shake. Tsk tsk.
Am i missing something? Which have shake?
Indeed I might be mistaken about the camera shake. It looks like the front blur/bokeh is of a disturbing type that made me think the picture had camera shake.
Can't let that stand in the way of a good laugh, though.
This is the first time I've tried building something like the O2, I was in a bit of a hurry to get it together and managed to put the U6 - 7912actg negative 12v regulator in backwards. The De-soldering process did not go well and suffice to say I need to find a replacement. Does anyone know what the requirements are for this? Jaycar, is the local electronics store in my area of New Zealand and they sell the Texas Instruments UA7912C UA7912C datasheet pdf datenblatt - Texas Instruments - NEGATIVE-VOLTAGE REGULATORS ::: ALLDATASHEET ::: which is has a rated current output of 1.5A. Otherwise things start to get a bit painful if I have to order the component from mouser for example who have a shipping rate of $39 to NZ not to mention the time it'll take.
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The UA7912C would work just fine if you get it in the KCS (TO-220) package. It has the same pinout. But it looks like Jaycar NZ does stock the 7912, here:
7912 -12V 1A Voltage Regulator - Jaycar Electronics
The actg letters don't matter for anything practical for the O2: non-industrial temperature range and super tight 2% voltage tolarance. t = TO-200 package and g just means lead free. A plain old (LM)7912 would work well. The power supply rejection ratio of the op amp amplfier chips in the O2 are such that the circuit isn't very persnickity about the regulators.
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