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[Review] JDS Labs Objective2 Amp - Page 4

post #46 of 60

Well, it will actually not stop charging at all, just the current when charging is so low, that batteries will never fail because of that. It's exactly like a car battery: if charged on the car will not overload, but if charged on dedicated powerful charger may blow away if left more than 12-16 hours. :)

 

So, no worries to overcharge O2. ;)

post #47 of 60

Hello all. I have been thinking on making myself an Objective 2 but when I went through that list of parts given out for its design some of them are discontinued or on backorder. So I started to wonder if their is a more updated list of parts for this device that is more current and maybe even some upgrades and such. Does anyone have an info on this?

 

And Yes I know I can just buy a Kit with all the parts but I kind of like buying such parts from my usual supplier. Plus if I do build this O2 I will be getting the PCB and Enclosure from JDS Labs but as for the rest of it I was going to order it elsewhere along with parts for a few other devices. I sort of wanted to add it all into one big order.

 

Anyways any info on if their is an updated list of parts would be appreciated. Thanks :)

post #48 of 60

There are many companies still building the O2 amp, mostly because it's great neutral and power sound, but also because of the price and DIY kits.

 

You can find original parts if you look harder or maybe better, try reading http://www.agdraudio.com/Page13.html for substitutes.

 

Cheers!

post #49 of 60
Quote:
Originally Posted by VectorRoll View Post
 

Hello all. I have been thinking on making myself an Objective 2 but when I went through that list of parts given out for its design some of them are discontinued or on backorder. So I started to wonder if their is a more updated list of parts for this device that is more current and maybe even some upgrades and such. Does anyone have an info on this?

 

And Yes I know I can just buy a Kit with all the parts but I kind of like buying such parts from my usual supplier. Plus if I do build this O2 I will be getting the PCB and Enclosure from JDS Labs but as for the rest of it I was going to order it elsewhere along with parts for a few other devices. I sort of wanted to add it all into one big order.

 

Anyways any info on if their is an updated list of parts would be appreciated. Thanks :)

 

Only the power jack has been discontinued. The O2 PCB was updated in 2013 to accept common 2.1x5.5mm barrel jacks, such as CUI p/n PJ-002A.

 

The original Bill of Materials contains suitable alternatives for other items.

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post #50 of 60
Quote:
Originally Posted by raoultrifan View Post
 

There are many companies still building the O2 amp, mostly because it's great neutral and power sound, but also because of the price and DIY kits.

 

You can find original parts if you look harder or maybe better, try reading http://www.agdraudio.com/Page13.html for substitutes.

 

Cheers!

Thanks that is exactly what I was looking for. Thanks :)

Quote:
Originally Posted by jseaber View Post
 

 

Only the power jack has been discontinued. The O2 PCB was updated in 2013 to accept common 2.1x5.5mm barrel jacks, such as CUI p/n PJ-002A.

 

The original Bill of Materials contains suitable alternatives for other items.

This is good to know as well. Thank you. :)

post #51 of 60
Can the popping sound damage the headphones? It inevitably happened to me about 3 times but no more than 5 seconds. Just paranoid.
post #52 of 60

I just bought a second power adapter for work and noticed the adaptor I ordered is only 12v.  I ordered Triad WAU12-200 W.  The site said it would work with Objective 2.  Then I read on the back it says 14v.  Then on another site it said this :

 

"The Objective2 strictly requires an AC-to-AC transformer, with minimum 13.50VAC output (14VAC+ recommended)."

 

Did I order the wrong PSU?  Is there a different brick for ODAC version.?  I have the o2+ODAC.

post #53 of 60

Taken from  http://nwavguy.blogspot.ro/2011/08/o2-details.html

 

"AC Wall Transformer – There has been some confusion over the wall transformer and it’s a critical component. Most wall transformers put out DC but the O2’s power supply requires at least 13.5 volts AC. The ideal transformer would be rated at 14 - 16 VAC and 400 mA or higher. In North America the Triad WAU12-200 from Mouser is rated at 12 volts but is really about 13.5 VAC with no load, and on normal 120 volt line voltage works fine for anything but full power sine wave testing or driving rare low impedance power hungry cans. If your line voltage is below 117 VAC  or 235 VAC, and/or you plan to drive difficult low impedance headpones (i.e. HiFiMan planars), I would suggest a 14+ VAC transformer at 400+ mA.The best Mouser transformers are the WAU16-400, 412-218054 or WAU16-1000 CUI. But those are more expensive than the WAU12-200."

 

So, basically you should be fine as long you're not getting into 300-600ohms headphones right now.

 

Regards!

post #54 of 60
But what you quoted says low impedance headphones. Wouldn't that be 32 ohms and lower. I know that doesn't make since but it the hifiman planters it quoted are 35ohms.
I actually have momentum at 16ohms even lower.
post #55 of 60

From http://nwavguy.blogspot.ro/2011/07/o2-headphone-amp.html graphs looks like output power for 16 ohms and 32 ohms headphones doesn't being affected at all when running from batteries and we're speaking about a massive voltage drop from 12V regulated to 8.4V batteries. So, if your power adapter is having 13.5V output, then feel free to test the voltage when powered on with music and headphones connected (just be sure you know what you're doing, 'cause a small short-circuit will make your O2 defective), but I really think it will be at least 12V.

 

If there's anything from your output voltage to loose by using this power adapter, then it's at most 0.5V on your headphones plug (instead of 7.3-7.5V you'll probably get around 7V), but hey...your opamps will be a bit cooler this way, same for mosfets. :)

 

In your place I would stick with this power adapter, but if you really believe this will impact the performance of your O2 in the future, maybe it would be better for you to return it and exchange it for a bit more expensive 14-16V power adapter.

 

Regards!

post #56 of 60
Quote:
Originally Posted by UNOE View Post

But what you quoted says low impedance headphones. Wouldn't that be 32 ohms and lower. I know that doesn't make since but it the hifiman planters it quoted are 35ohms.
I actually have momentum at 16ohms even lower.

 

The author refers not to ordinary low impedance headphones, but "rare low impedance power hungry cans", i.e., planar orthodynamics.

 

Triad's WAU12-200 was the default North American power adapter for Objective2 for years, and works well. We've since switched to another transformer model to ensure maximum long-term reliability (WAU12-200 failed at ~2% rate annually).

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post #57 of 60

Thanks guys

post #58 of 60
how about it with k701?
post #59 of 60

What do you mean? I own K700 and O2 is driving it perfectly with 2.5X gain, so no worries at all.

post #60 of 60
Can someone nake a comparison between the 02 and cypher labs duet? It would be very helpful. Thanks!
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