[wolfetan44]

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Did you get the wall plug for the O2?
http://www.jdslabs.com/item.php?fetchitem=38

Sorry I forgot to mention that I'm using an a/c adapter from my router, so the amp is turned on with red light
 
and from my desktop, I see Odac in volume control area, but no sound~
 
Help me~~~~
 
Edit:  A/c adapter from the router is 12v and 1amp. I'm not getting any sound from the amp, is it because the adapter isn't putting out enough power?
 
edit: I'm guessing that I'm not getting any sound because the adapter is probably ac to dc output? arg...
 
Edit: Problem was with the adapter

Thats what I was thinking..
_______________________________________________
 
How do I use the O2 portably? 

 

[adydula]

You need an AC to AC adapter!!
 
They are very different..
 
Alex

 

[miceblue]

Quote:

 
How do I use the O2 portably? 

If you bought the O2 as a separate unit and it has batteries installed...you just use it normally.

 
Source -> 3.5mm O2 source jack
Headphones -> 3.5mm O2 headphone jack
Turn-on source, set volume, play music
Turn volume knob on O2 to low volume, set gain switch to low, turn-on the O2, adjust volume knob accordingly
 
JDS Labs O2's battery lasts about 8-ish hours at 1.0x gain, max volume knob level, source volume set at public transit bus-listening levels, 32-ohm headphone.

 

[autoteleology]

I've had my O2 for a while, and I've found it to be superb.

I just got my ODAC, and I'll tell you guys how I feel about it... as soon as I find my fragglesnaggin Q701 cable.
 
Seriously, where has it walked off to?

 

[Crispy808]

I'm adding a 1/4" Neutrik headphone jack to my O2, but I'm not sure how to wire to P2.
 
Per the designer's site, "for P2 the two pads closest to the edge of the board are ground."  Which of the other two pads correspond to the right and left channels? 

 

[lorriman]

I'm thinking of getting a o2+odac combo for my ES10...
Can someone comfirm if they can really fit the odac under the o2 then add in batteries?
TIA =D

Yes, I did this with my own O2. The ODAC fits perfectly underneath the O2 circuitboard. Quite a marvellous coincidence; I don't think the designer did this deliberately. As someone else mentioned: you need to tape up the bottom of the ODAC with electrical insulating tape since the circuit board traces would otherwise be in direct contact with the aluminium of the case.

There are also two methods of doing this. If the ODAC is placed upside down, then the aluminium case needs filing down.

Pics here: http://www.diyaudio.com/forums/headphone-systems/193977-objective2-o2-headphone-amp-diy-project-251.html

 

[adydula]

lorriman...
 
thanks for posting the link !!
 
Alex

 

[k186]

At risk of stating the obvious, it should be R17 that needs to be clipped, not R27 (looks like a typo, plus there is no R27).  If this was already addressed in a later post, apologies in advance.

Edited!  Thanks, stv014! duh, I dunno what I was thinking (late-night post).
Quote:

With ODAC the gains should be no more than 3.5x anyway, so take the 6.5x option down to 1x. I wouldn't recommend changing the 2.5x to 1x as that would leave the 6.5x option, which is mostly useless (at full volume, it will cause clipping no matter what you set the volume knob to).

Clip one end (or both) of the resistors marked R19 and R23. The idea is to effectively remove them from the circuit, so it's an open circuit there instead of the resistor. The leads are thin, so you can clip them with about anything. You see that they're right next to the volume control knob. That reduces the gain to 1x.
If you really wanted to modify the 2.5x down to 1x instead, clip R27 and R21 (and not R19 / R23).

 

[stv014]

Quote:

At risk of stating the obvious, it should be R17 that needs to be clipped, not R27 (looks like a typo, plus there is no R27).  And I think clipping / removing either one of R17 or R21 should suffice for dropping the low gain to 1x.  If this was already addressed in a later post, apologies in advance.

 
Clipping only one of the resistors will drop the gain on only one channel.

 

[Stratok]

Just ordered mine cant wait

 

[muad]

After using some cheap tube amps and audio-gd fun this combo is a breath of fresh air. I believe the o2/odac with my iems and hd650 are as far as I need to go with headphones. If only I could use it as a preamp to a nice power amp in the future...

 

[miceblue]

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Hello,
 
I'm using ODAC + O2, but the gain is waaay too much for my 650's if I keep the volume in the OS at maximum.
 
I'd like to switch to x1 gain instead of x2.5, which I heard wasn't too complicated to do. Is there a guide somewhere? Google has not come up with anything straightforward.
 
Thanks

I can't read circuit diagrams very well, so maybe this can help someone in the future.

 

[k186]

Quote:

I can't read circuit diagrams very well, so maybe this can help someone in the future.

It's right.  F--- me.  That's 2 mistakes.  I'm gonna stop posting altogether.  Wow.  I completely misread your picture miceblue, you're right.

 

[miceblue]

Quote:

Quote:

I can't read circuit diagrams very well, so maybe this can help someone in the future.

I think you have 19/23 and 17/21 switched in this pic.

I dunno. I bought my O2 from JDS Labs and John sent me that photo. I clipped the rightmost resistors since the default 2.5x/6.0x gain was too much for me and now I have 2.5x/1.0x.

 

[moshen]

Quote:

I dunno. I bought my O2 from JDS Labs and John sent me that photo. I clipped the rightmost resistors since the default 2.5x/6.0x gain was too much for me and now I have 2.5x/1.0x.

Yea, I can confirm that photo is correct.