O2 AMP + ODAC

[Dark_wizzie]

  Hi all,
 
I'm planning on getting the 02+odac for a future hd650/600 purchase.
 
I currently own a pair of ps500e's.
 
Is the impedance of the grado's too low to be used with the 02+odac? Will there be a humming noise?
 
I'm very new to this sorry.
 
One more thing, is it best to turn my macbook volume and vlc player all the way down and let the volume on the amp/combo do the rest or vice versa?
 
Thanks in advance guys.

Should be the other way around... The digital volume should be at 100% for everything: Windows, VLC, Foobar, Youtube. And then you adjust the volume knob on the O2 accordingly. However... the gains here are really just theoretical. And with the O2 and an easy to drive headphone, things get really loud really quickly, so you'll be turning the volume knob pretty low. And too low can cause channel imbalance. (Say, under 8 or 7 oclock position)
 
The impedance of the O2 is very low, it's not an issue. The humming should be from the noise floor, right? That should be fine too.
 

  Thanks @Dark_wizzie, @castleofargh and @adydula.

No problem, I'm glad I helped in some way.

 

[gradofans]

I'm looking for a cheap DAC now , maybe it's proper for me to get an ODAC ...
But I can't find anywhere to try it. ...

 

[jring]

  Does anyone know if the o2 will run off ac with the batteries removed?

 just fine.
 
Joachim

 

[jring]

  I'm looking for a cheap DAC now , maybe it's proper for me to get an ODAC ...
But I can't find anywhere to try it. ...

 
It's usually sold only by a few companies and even fewer have a showroom. So your best bet is to go to a meet or find some friendly head-fier with one in your area.
 
Joachim

 

[vertical]

It's usually sold only by a few companies and even fewer have a showroom. So your best bet is to go to a meet or find some friendly head-fier with one in your area.

Joachim

I second that. Meets are a great place to hear a lot of equipment, meet great people, and find out about new music

 

[jasonhanjk]

  Does anyone know if the o2 will run off ac with the batteries removed?
 

 
Nope. The AC are meant to charge the batteries. Removing the batteries and you won't get your ground.
It will work if you add 2 caps and resistor divider but there would be more noise / voltage unbalance / DC at output.

 

[mcandmar]

   
Nope. The AC are meant to charge the batteries. Removing the batteries and you won't get your ground.
It will work if you add 2 caps and resistor divider but there would be more noise / voltage unbalance / DC at output.

^ utter nonsense.

 

[mikeaj]

  Nope. The AC are meant to charge the batteries. Removing the batteries and you won't get your ground.
It will work if you add 2 caps and resistor divider but there would be more noise / voltage unbalance / DC at output.

 
No, that's not how it works. Just check the circuit diagram. The AC goes into half-bridge rectifiers into filters and 7812 / 7912 linear regulators to generate +12 V / -12 V rails. It's those +12 V and -12 V rails that charge the batteries and also power the electronics (the three op amps). If the AC is disconnected, the voltage rails drop to the battery voltages instead. The ground is from the AC input. Whether or not the batteries are in doesn't affect the power delivery other than drawing some amount of current from the rails.
 

Check the top side.
 
There are many people who have build or gotten an O2 without the batteries. Many O2 / ODAC combos people sell don't come with batteries.

 

[headwhacker]

   
Nope. The AC are meant to charge the batteries. Removing the batteries and you won't get your ground.
It will work if you add 2 caps and resistor divider but there would be more noise / voltage unbalance / DC at output.

Sure you can. O2 can be powered and operated from AC without the batteries. Otherwise, How do you think the O2/ODAC combos work? The ODAC board occupies the space where the batteies are placed.

 

[castleofargh]

last time I emailed JDS for what was in the end a dumb question(don't ask me I'm ashamed), he answered me as if I was a very interesting person with a good question in less than 40mn. so maybe you should just email the guy where you bought it or plan to buy it. ^_^
I know the odac/o2 combo can have some very minor changes compared to both bought separately (usually stuff you can undo in 20sec and a soldering iron so I don't expect a radical power supply change in the schematics).

 

[Solrighal]

My O2 has stereo RCA outputs. The lower gain is 1x (unity) can I output the signal from my O2 to my Marantz integrated stereo amp?

 

[adydula]

I have an 02 without batteries and it runs on AC only??
 
Must be magic?
 
Alex

 

[castleofargh]

at last something magic about the O2!!!!!
we have been waiting for a sign for so long, something that measurements wouldn't explain. a subjective reason to want it that wouldn't be some stupid idea of transparency and low noise.
 
"O2, it runs without batteries or legs!"

 
what a great day.

 

[headwhacker]

  at last something magic about the O2!!!!!
we have been waiting for a sign for so long, something that measurements wouldn't explain. a subjective reason to want it that wouldn't be some stupid idea of transparency and low noise.
 
"O2, it runs without batteries or legs!"

 
what a great day.

So does it mean O2/ODAC is now a going audiophile?

 

[Dark_wizzie]

  So does it mean O2/ODAC is now a going audiophile?

One factor of an amp/dac being an audiophile item is high price, which the Objective does not deliver.