O2 AMP + ODAC

[r010159]

   
Or you can waste even more time and manually shape out a panel out of clear plastic. Just to avoid drilling two extra holes (which makes no sense because I had to drill and expand 11 holes regardless)
 
I also realised that we of the O2 Output Booster board thread, have began hijacking this thread. Unsure whether I should feel sorry or not.

 
It is still O2 related and also IMO a nice break from the regular discussion. 

 

  [good info deleted]
 
The booster board just plugs right into the O2 amp  in place of the two NJM4556A chips (the ones next to the battery in the middle).  You unplug those two chips then plug in the booster board.  It slides into the top slot in the standard O2 B2-080 case.  There are 3 wires that go from the booster board to the O2 PCB that have to be soldered on.  Two are grounds, one going to either middle battery terminal and the other in front going to a resistor.  The 3rd one is for the no-thump relay circuit and goes from the booster board to another resistor in the power management section of the O2.   Pictures of exactly where those 3 wires attach are posted at the google drive link.  After all the surface mount soldering one does in soldering up the booster board those 3 wires will be a piece of cake!

 
[deleted]
 
Good questions!

 
Surface mount chips? I do not know how to reliably solder them. I understand there is soldering paste for this. But I will pose my further fabrication questions on the separate O2 booster board thread. Other than that, I think this project would be a "no brainer" decision for me. It will turn my O2 + ODAC into the desktop amp it aspires to be! Oh yes, now that I mentioned it, will this also work for my setup (O2 + ODAC)?
 
BG

 

[agdr]

   
Or you can waste even more time and manually shape out a panel out of clear plastic. Just to avoid drilling two extra holes (which makes no sense because I had to drill and expand 11 holes regardless)
 
I also realised that we of the O2 Output Booster board thread, have began hijacking this thread. Unsure whether I should feel sorry or not.

 
Lol!  Hey I like how your panel turned out.

   This thread had kind of died off it seems, so a kick in the pants probably hasn't hurt.  Since the last booster board from this run went out the door though I am going to essentially shut up in this thread and post any new stuff in the DIY forum thread for the project.  Feel free to PM me with questions too.  Thanks again to the mods for even allowing discussion of an O2-related project in the first place!

 

[JacobLee89]

  Other than that, I think this project would be a "no brainer" decision for me. It will turn my O2 + ODAC into the desktop amp it aspires to be! Oh yes, now that I mentioned it, will this also work for my setup (O2 + ODAC)?
 
BG

 
It works, and to a point it's giving me enough of an improvement to keep me happy with my HD650s.
 
Waiting patiently on the updates on the USB isolator over in the DIY threads so I can squeeze out some extra performance out of my ODAC.

 

[Twolf]

Has any of you guys tried the O2 amp with AKG K501 headphones, or something else from that era (K400/K401/K500)?

 

[bar1]

Yes, O2 + K501 sounds great.

 

[anthk]

I have a odac+o2 combo. There are different posts on the internet saying how you could use just one of the component for various functions. I am hoping that other owners could verify the facts for me please.
1. Power on the combo. Use the line-in pot then the combo becomes an amp.
2. Power OFF the combo. The line-in pot somehow becomes a line out of the ODAC.
3. If I want to connect a speaker to the combo, should I
 a)  power on the combo and use the headphone out as usual , or
b) power  off the combo and treat the line-in as line out from the dac?
 
 
 
Thanks.

 

 

[Veetastic]

  I have a odac+o2 combo. There are different posts on the internet saying how you could use just one of the component for various functions. I am hoping that other owners could verify the facts for me please.
1. Power on the combo. Use the line-in pot then the combo becomes an amp.
2. Power OFF the combo. The line-in pot somehow becomes a line out of the ODAC.
3. If I want to connect a speaker to the combo, should I
 a)  power on the combo and use the headphone out as usual , or
b) power  off the combo and treat the line-in as line out from the dac?
 
 
 
Thanks.

 
 

I also own an O2 + ODAC combo from mayflower and these are some of my observations.
 
I can't verify anything. I am not really sure if the audio that I am getting from the line-in is actually from the ODAC or not. However, there is in fact audio that is coming from the line-in once the O2 amp is turned off. Whatever indication this is I do not know. Even when the power is on the line-in still acts as an output for what I believe to be the ODAC. The volume knob does not affect the actual output of the line-in. I think that while the combo is still connected to the computer via usb, the line-in will continue to act as an output for the ODAC. 
 
I suppose this would be useful if you had another amp and wanted to use the ODAC as the D/A converter or you simply wanted to test different D/A converters. As far as speakers go, you will need an amp for them and I do not think directly connecting them to the ODAC which has no power output is ideal. Of course, this depends on what type of speakers you run too. 
 
There seems to be a lot of flexibility with the combo as far as I know and you can personally try out what you think works the best for you since you already have the unit with you. Good luck.

 

[anthk]

  I also own an O2 + ODAC combo and these are some of my observations.
 
I can't verify anything. I am not really sure if the audio that I am getting from the line-in is actually from the ODAC or not. However, there is in fact audio that is coming from the line-in once the O2 amp is turned off. Whatever indication this is I do not know. Even when the power is on the line-in still acts as an output for what I believe to be the ODAC. The volume knob does not affect the actual output of the line-in. I think that while the combo is still connected to the computer via usb, the line-in will continue to act as an output for the ODAC. 
 
I suppose this would be useful if you had another amp and wanted to use the ODAC as the D/A converter or you simply wanted to test different D/A converters. As far as speakers go, you will need an amp for them and I do not think directly connecting them to the ODAC which has no power output is ideal. Of course, this depends on what type of speakers you run too. 
 
There seems to be a lot of flexibility with the combo as far as I know and you can personally try out what you think works the best for you since you already have the unit with you. Good luck.

http://www.techpowerup.com/reviews/JDSLabs/O2_ODAC/1.html

Look at the last sentence of the "spec " . Seems like the combo has more functions than it is advertised

 

 

[r010159]

Reading a review of the O2 + ODAC at http://www.techpowerup.com/reviews/JDSLabs/O2_ODAC/4.html
 
The specs there list the Op Amps as swappable. Is this true. Considering the talk about the O2 booster board, I am not so sure.
 
BG

 

[Poladise]

Scary behaviour from my O2. Extremely loud buzz came through the headphones. Like a 60Hz square wave at what seemed like the amps maximum output. Pulled the headphones off after about 1 second and I powered off the amp another 2 seconds later just praying it hadn't damaged my LCD-2s. I'm guessing the battery was empty, which usually shuts it off with a thud, but this time I can only guess it was stuck between the ON/OFF state causing it to power up & down rapidly.
 
Plugged in some cheap headphones and powered on again, buzz still there. Plugged on the mains and the amp worked normally (LCDs were OK too). I'm never using this on battery again and it's made me reluctant to even use it on mains tbh. Mine is the Epiphany Acoustics EHP-O2. Has anyone else experienced this?

 

[James neutron]

I experienced occasional buzzing or popping noise in my ODAC as well. Troubleshooting the issues I found either one of the batteries to be slightly dislodged and did not make a perfect connection anymore or it drained faster than the other and the amp failed to power off correctly. Measuring the voltage of your batteries might give you some insight into this.
After a full recharge things should go back to normal. If they don't, contacting the manufacturer is recommended.
For me personally battery use with the O2 is iffy and chose to power it by mains only.

 

[wewewho77]

Scary behaviour from my O2. Extremely loud buzz came through the headphones. Like a 60Hz square wave at what seemed like the amps maximum output. Pulled the headphones off after about 1 second and I powered off the amp another 2 seconds later just praying it hadn't damaged my LCD-2s. I'm guessing the battery was empty, which usually shuts it off with a thud, but this time I can only guess it was stuck between the ON/OFF state causing it to power up & down rapidly.

Plugged in some cheap headphones and powered on again, buzz still there. Plugged on the mains and the amp worked normally (LCDs were OK too). I'm never using this on battery again and it's made me reluctant to even use it on mains tbh. Mine is the Epiphany Acoustics EHP-O2. Has anyone else experienced this?

Mine also behave like those of yours
Are there more Epiphany Acoustics that shows this kind of behaviour?
Makes me plug cheap HP first before plugging my HE500

 

[A1Dan]

Scary behaviour from my O2. Extremely loud buzz came through the headphones. Like a 60Hz square wave at what seemed like the amps maximum output. Pulled the headphones off after about 1 second and I powered off the amp another 2 seconds later just praying it hadn't damaged my LCD-2s. I'm guessing the battery was empty, which usually shuts it off with a thud, but this time I can only guess it was stuck between the ON/OFF state causing it to power up & down rapidly.

Plugged in some cheap headphones and powered on again, buzz still there. Plugged on the mains and the amp worked normally (LCDs were OK too). I'm never using this on battery again and it's made me reluctant to even use it on mains tbh. Mine is the Epiphany Acoustics EHP-O2. Has anyone else experienced this?

Same thing happened with my JDS Labs O2 a couple of days ago. Turns out I hadn't plugged the power adapter in fully and the battery had completely drained.

 

[chuck8403]

Same thing happened with my JDS Labs O2 a couple of days ago. Turns out I hadn't plugged the power adapter in fully and the battery had completely drained.

I have had a few of the Triad power supplies shipped to me bad. Did not realize they were bad until I bought a O2+ODAC from JDS Labs with a bad power supply and the LED did not light up. I tried another that I had and it lit up. That may be the reason your batteries discharged.

 

[agdr]

  Scary behaviour from my O2. Extremely loud buzz came through the headphones. Like a 60Hz square wave at what seemed like the amps maximum output. Pulled the headphones off after about 1 second and I powered off the amp another 2 seconds later just praying it hadn't damaged my LCD-2s. I'm guessing the battery was empty, which usually shuts it off with a thud, but this time I can only guess it was stuck between the ON/OFF state causing it to power up & down rapidly. 
 
Plugged in some cheap headphones and powered on again, buzz still there. Plugged on the mains and the amp worked normally (LCDs were OK too). I'm never using this on battery again and it's made me reluctant to even use it on mains tbh. Mine is the Epiphany Acoustics EHP-O2. Has anyone else experienced this?

 
The problem is a bit of a design hiccup with the O2.  The batteries tend to rise up in voltage a little bit once the load is cut off (when the battery is low and the O2's mosfets turn off).   If they rise up too much in voltage the O2's power management circuit thinks the batteries are charged up again and turns the mosfets back on.  That load causes the battery voltage to drop again, the O2 mosfets cut off again, and the whole thing repeats at that 60Hz-or-so rate.
 
The best quick solution is to try changing your batteries to a newer (fresher) pair or a different brand.  The problem shouldn't show up at all with the O2 running on AC.
 
Here is a permanent fix, below in the red circle, but it involves whipping up a little circuit board. It is a modification I posted a year or two ago on another forum.  The resistor, capacitor, and two additional transistors form a latch circuit that keeps the O2's power management circuit off permanently, until the next on/off switch toggle, once the batteries are low and toggle the O2's power management circuit mosfets.  The parts to the right of the red circle are just the O2's power management circuit. The modification doesn't affect the sound in any way since it is just wired into the O2's power management circuit that decides when to cut off the O2 batteries. 
 
The 2.2uF capacitor needs to be ceramic or film, not electrolytic (too much leakage). The two transistors can be common 2N7000's if they are a version that have +/-30V maximum gates rather than the more common +/-20V gates.