[LouisLoh]

  Just take them out and run on AC and see...
 
Alex

 
Hi Alex,
 
I've taken the batteries out and they don't run with just the AC plugged in. Am I missing something really obvious?
 

   
Hum does your O² have Internal Batteries ?  I got something similar only when batteries were runing low , but yours can be defective after charge / decharge cycle

Unfortunately the noise is still present. Should I bother getting new batteries?

 

[adydula]

Hmmm,
 
Thats odd to me.
 
I have 2 O2's,
 
They both run without batteries when powered up by using the AC to AC wallwort.....
 
Did you build your O2 or buy from a commercial retailer?
 
If you bought it from a retailer, contact them about not running on AC?
 
Did you get a AC to AC adapter?
 
Alex

 

[LouisLoh]

  Hmmm,
 
Thats odd to me.
 
I have 2 O2's,
 
They both run without batteries when powered up by using the AC to AC wallwort.....
 
Did you build your O2 or buy from a commercial retailer?
 
If you bought it from a retailer, contact them about not running on AC?
 
Did you get a AC to AC adapter?
 
Alex

 
I bought it from a commercial retailer and I am using an AC-AC adapter.

 

[MrMateoHead]

I get a similar noise but only when the batteries are essentially drained. When I plug in the wall wart, all is well.
 
When I opened up my O2 to fix the ground wire to stop the annoying staticky noise on the input jack, I noticed one of my batteries was too loose. The other is snapped right in, but I had to put a little cardboard in the housing to prop the poorly seated battery.
 
Ever since that time, I swear the battery life has been a bit shorter, but that could be my own paranoia. But it did make me wonder if 1 of the batteries might be bad or going bad. Can the O2 run on a single battery? Can it make that noise if the connection isn't solid?

 

[LouisLoh]

  I get a similar noise but only when the batteries are essentially drained. When I plug in the wall wart, all is well.
 
When I opened up my O2 to fix the ground wire to stop the annoying staticky noise on the input jack, I noticed one of my batteries was too loose. The other is snapped right in, but I had to put a little cardboard in the housing to prop the poorly seated battery.
 
Ever since that time, I swear the battery life has been a bit shorter, but that could be my own paranoia. But it did make me wonder if 1 of the batteries might be bad or going bad. Can the O2 run on a single battery? Can it make that noise if the connection isn't solid?

I tried running it on 1 battery. Wouldn't work. I also rechecked the battery connections several times, to no avail.

 

[adydula]

The O2 should run without batteries using the AC to AC walwort....if it doesnt you have other issues.
 
Please check this out if you havent already. If it works with AC only with no noise, hum, oscillation then its the batteries I would guess.
 
Wont run on one battery, replace them and see what happens.
 
Alex

 

[gargani]

Can I connect from the tape output jacks on my stereo reciever to the o2?. The owners manual specifies the tape out as 150mv output and 2.5kohms impedance.

 

[Smugsie]

Spoiler: My initial messy post

I used to use a tube amp that had tubes that costed me $75, plus rhodium plated Q701 silver cables that costed $100.
After my tube amp died and the jacks on the Q701 cables decided to fall apart (literally!), I decided to go back to my ODAC/O2 and stock cables.
I'm using this $20 (Texas Instruments LME 49720HA) solution with the Q701's stock cables and this combination gave me the same result compared to my previous overpriced upgrade.

The treble is smooth but more detailed, the 2khz spike in the Q701's are smoothed out, mids seem to be faster and warmer and sweeter.
The overall sound is wetter, not bad for a $20 side-grade. Although sub-bass took its' toll and there's a bit less extension.

I should note that all the differences I mentioned above are just tonal to my ears. It's not a night and day difference unless if you're someone like me who has spent over 2 years with a single headphone and source.

Good mids + highs but iffy bass. = German Telefunken Vacuum Tubes = TI LME 49720HA
Good bass + intimacy = Russian Voskhod Vacuum Tubes = NJR NJM4556

In a nutshell: I went in a COMPLETE CIRCLE, except with solid state! 

 

[ck2323]

Does the Mayflower Objective2 + ODAC Rev. B Combo have the ability to use the dac only with an external amp? 

 

[lvince95]

  Does the Mayflower Objective2 + ODAC Rev. B Combo have the ability to use the dac only with an external amp? 

Yes it does of course. I would rather go with JDS though, their customer service and quality control is much better than Mayflower's.

 

[WilliamLeonhart]

  Does the Mayflower Objective2 + ODAC Rev. B Combo have the ability to use the dac only with an external amp? 

Yes it does. My old one had RCA outputs at the back.
 
But, same as lvine, I think you should go with JDS. My Mayflower O2 ODAC combo had 5x gain and clipped a lot. The new version only has 3.3x gain but if given a choice I'd go with JDS. I owned a diy combo made from JDS boards and even that sounded better than the Mayflower one.

 

[ck2323]

 
Yes it does of course. I would rather go with JDS though, their customer service and quality control is much better than Mayflower's.

 

  Yes it does. My old one had RCA outputs at the back.
 
But, same as lvine, I think you should go with JDS. My Mayflower O2 ODAC combo had 5x gain and clipped a lot. The new version only has 3.3x gain but if given a choice I'd go with JDS. I owned a diy combo made from JDS boards and even that sounded better than the Mayflower one.

Thanks for the replies guys! Looks like the JDS will be the one I get. How exactly does the DAC only mode work? Through the RCA ports? 

 

[WilliamLeonhart]

   
Thanks for the replies guys! Looks like the JDS will be the one I get. How exactly does the DAC only mode work? Through the RCA ports? 

You can plug external amp into the headphone-in port of the O2... That port has double functions.
 
Or you may buy the amp and DAC separately. One of my friends told me the ODAC will output better signal when not attached onto the board of the O2, but I'm not sure how many percent of truth is there in that.

 

[ck2323]

  You can plug external amp into the headphone-in port of the O2... That port has double functions.
 
Or you may buy the amp and DAC separately. One of my friends told me the ODAC will output better signal when not attached onto the board of the O2, but I'm not sure how many percent of truth is there in that.

Huh...that's interesting. I didnt think about that. 

 

[Hammy]

I'm not a fan of starting new threads for the sake of it, so I'll post these ramblings here.
 
Need someone to talk me out of getting the O2+ODAC to replace my FiiO E10K, which is what currently powers my Fidelio X2.  It'd work out at about 3x the price of the E10K and I'm unsure it would provide a noticeable increase in sound quality.
 
DISCLAIMER: I'm not a headphone collector, can't hear above 15khz, 90% of my listening is TV/movies, and I have trouble noticing a difference from onboard ALC892 compared to the E10K.
 
Talk me down!
 
EDIT: I only just discovered that both the E10K and ODAC RevB share the same PCM5102A chip.