[jimbop54]

Can the Burson V5-D op amps be installed in the JDS labs O2/ODac combo?

 

[drteming]

Can the Burson V5-D op amps be installed in the JDS labs O2/ODac combo?

 
It's a DIP-8 package so it should fit and the specs seem fine. Physically, you won't be able to get it back in its original case as the Burson is 29mm tall, which is as tall as the entire case.  Also the O2 is a dual stage design with one gain opamp (NJM2068) and 2 output opamps (NJM4556), so you are looking at 3 at $70 per pop.  The O2 was designed around opamps.  If you want a discrete amp, just get a discrete amp.

 

[WilliamLeonhart]

WOW I DID NOT KNOW THE O2 USED OPAMP
 
This changes everything!

 

[schmalgausen]

Have anyone compared ODAC with HiFiME products? 

 

[WilliamLeonhart]

  Have anyone compared ODAC with HiFiME products? 

Did. Big nope. If you won't get to 350/400 USD then the ODAC is best sound you can have.

 

[Rado2]

  Which gains should I use for the K701?

This depend on your input level.
 
If your input level (source) is 2.1V RMS (like in the ODAC combo) you should not go over x3.33 gain (if I remember O2 tops near 7V).
For your K701, which are 105dB/V this mean... 115dB I think... Anyway, its enough to overload your ears or even burn the phones (they are rated 200mW).
 
If your source is low, like 0.775V you have to increase the gain correspondingly. If you buy O2 from store, they can help you decide.
 
Very common setup is to have 1 and 3.33 gain I think. I see this on many places and mine is like that too.
 
For example I have HD700 which are harder to drive than k701, and my source is the ODAC, I use only the x1 gain and very, very rare turn over the half of the knob.

 

[raoultrifan]

Hi, 
 
My ODAC has 1.92 V RMS @ 1 KHz, measured with my scope, in case it helps.
 
Cheers!

 

[rizzotti91]

Hello, I've a question about the O2. If I buy the "mobile version", can I use it plugged in the power source? If yes, will the battery deteriorate?

 

[Jiexi]

  Hello, I've a question about the O2. If I buy the "mobile version", can I use it plugged in the power source? If yes, will the battery deteriorate?

Yes, and yes. You can't avoid battery degradation. Battery should be replaceable, so no worries.

 

[barontan2418]

Hi. Just wondering if the O2 has any built in protection to cut off charging when the batteries are fully charged. Reason I'm asking is I accidentally left the charger in overnight and the batteries were flat today when I tried using the amp? And batteries are not that old.

 

[Jiexi]

Hi. Just wondering if the O2 has any built in protection to cut off charging when the batteries are fully charged. Reason I'm asking is I accidentally left the charger in overnight and the batteries were flat today when I tried using the amp? And batteries are not that old.

Battery charge protection circuits are pretty standard. Were you charging from a wall port? It almost sounds like you were charging with an usb battery, the usb battery ran out of charge, and started draining power back from the O2.

 

[barontan2418]

Battery charge protection circuits are pretty standard. Were you charging from a wall port? It almost sounds like you were charging with an usb battery, the usb battery ran out of charge, and started draining power back from the O2.

Hi. No I was charging using the normal AC adapter from the mains. Giving it another go now. Thanks for your reply.

 

[WilliamLeonhart]

Does anyone here roll opamps on the Objective2? From what I understand, it seems that the U2 opamp won't affect sound quality, the U3 and U4 opamp will be used for low-gain and the U1 will be activated in high-gain. Is it true? If not, please correct me. Cheers.

 

[raoultrifan]

Many of us swapped opamps in O2, so feel free to search inside this thread about it. Now, depending on what you need to gain, the original opamps are the best price/value possible and they also have a very good THD and a very low-noise, so by using the original opamps you can be sure that O2's background will be really "dark".
 
For me, using Burson SS V5 in voltage amplification stage improved soundstage, details and musicality (http://www.head-fi.org/t/616331/o2-amp-odac/4965#post_12382477), but I did some other mods to my O2 as well (http://www.head-fi.org/t/616331/o2-amp-odac/4905#post_12282731).

 

[WilliamLeonhart]

  Many of us swapped opamps in O2, so feel free to search inside this thread about it. Now, depending on what you need to gain, the original opamps are the best price/value possible and they also have a very good THD and a very low-noise, so by using the original opamps you can be sure that O2's background will be really "dark".
 
For me, using Burson SS V5 in voltage amplification stage improved soundstage, details and musicality (http://www.head-fi.org/t/616331/o2-amp-odac/4965#post_12382477), but I did some other mods to my O2 as well (http://www.head-fi.org/t/616331/o2-amp-odac/4905#post_12282731).

 
Thanks for the tips.
Right now my O2 look like this: 

I have not tried switching the V5i to voltage gain yet, so I don't know how great it can improve the sound. But so far I'm enjoying this special "Burson O2" greatly. One certain thing that can be praised is the bass. My K7xx sound much fuller than before and on some songs it can reach basshead levels. Details retrieval is good and soundstage is spacious. The inherent "dry" trait of the O2 is no where to be found, although the change is actually subtle.