[MrMateoHead]

Lets turn from theory and opinion for a moment to a technical issue I am having!
 
Anyone else get channel cut out with a mere gentle "wiggle" of the 02's input connector? Lately I am needing to give it a little wiggle to correct static / channel cut out issues. I think it also sometimes happens at the headphone out. Is that symptomatic of possible soldering issue inside, or maybe just a "feature" of the low-cost connectors?

 

[adydula]

I never had that issue but had a ac power issue with a connector that if wiggled just right I lost power!!
 
I used some deoxit and mild bending of contacts and its fine now.
 
A.

 

[tomb]

  Lets turn from theory and opinion for a moment to a technical issue I am having!
 
Anyone else get channel cut out with a mere gentle "wiggle" of the 02's input connector? Lately I am needing to give it a little wiggle to correct static / channel cut out issues. I think it also sometimes happens at the headphone out. Is that symptomatic of possible soldering issue inside, or maybe just a "feature" of the low-cost connectors?

The only question about a 3.5mm jack failure is when, not if.  You might be able to blame it on the "low-cost" selection, but I don't think so.  There is simply a limitation of geometry when it comes to 3.5mm jacks.  The contact area is super small, so any small potential for corrosion has a huge impact on connectivity.  Similarly, the spring strengths in the size of the metal required fatigues rather easily, also causing intermittent contact problems.  It's the nature of the beast in 3.5mm connectors.  You are best to keep things plugged in as continuously as you can. 
 
Just an FYI, but the physical geometry critical point is well exceeded with 1/4" connectors.  Equipment stored up and un-used for decades often makes perfect electrical contact with 1/4" connectors.

 

[Xenophon]

For my O2/ODAC combo keeping the 3.5 mm jack plugged in all the time is exactly what I do, I use a female 1/4" to male 3.5 mm connector in which I plug my headphones but the connector itself just stays plugged in all the time.  Same with the USB-input, BTW.  In general, the less swapping out, the longer things will last.  Though I have to say that even icd the unit were to fail catastrophically right now, I'd still consider it a good deal after 2.5 years.  And it'd provide me with a good excuse for buying agar's new and improved version, would just need to find a solution for the power supply issue, given EU regulations.  It would be nice to use the electronics in question but provide a high quality pot, luxurious aluminium case, billet Al knob, 1/4" output etc.

 

[mcandmar]

  For my O2/ODAC combo keeping the 3.5 mm jack plugged in all the time is exactly what I do, I use a female 1/4" to male 3.5 mm connector in which I plug my headphones but the connector itself just stays plugged in all the time.  Same with the USB-input, BTW.  In general, the less swapping out, the longer things will last.  Though I have to say that even icd the unit were to fail catastrophically right now, I'd still consider it a good deal after 2.5 years.  And it'd provide me with a good excuse for buying agar's new and improved version, would just need to find a solution for the power supply issue, given EU regulations.  It would be nice to use the electronics in question but provide a high quality pot, luxurious aluminium case, billet Al knob, 1/4" output etc.

 
Whats the issue with the power supply?

 

[Xenophon]

Wall power adaptors with a transformer are outlawed (energy efficiency) you need a switching power supply.  And none of those will output AC, which the design requires....

 

[mcandmar]

Ahh yes i had forgotten about that.  I'll refrain from ranting about stupid EU laws since your in Belgium

 
Might i suggest your build your own, buy an encapsulated toroid and put it into a box..

 

[headwhacker]

I am trying to determine the one difference between the C5 and O2. The thought I have is the O2 is a bit more transparent. Anyone want to take a stab at this?

PS: I needed some warranty work on the C5 which turned our to be a trivial problem. The unit was received, fixed, and shipped the same day. Thanks JDS Labs.

 
I had the C5D and yes I can say O2 is more transparent. The only thing you have with C5/D over O2 is portability. Everything else, O2 hands down. Suffice to say I sold the C5D and still enjoying O2.

 

[SilverEars]

   
I had the C5D and yes I can say O2 is more transparent. The only thing you have with C5/D over O2 is portability. Everything else, O2 hands down. Suffice to say I sold the C5D and still enjoying O2.

I agree with this, but I have ODAC/O2 combo.  I tried the C5D, and it didn't sound as natural as the ODAC/O2 combo.  It sounded too tight and refined to the point where it sounded too artificial, especially the bass.  In other words, it wasn't as transparent and natural sounding as the ODAC/O2.  I don't like to use ODAC/O2 with my high end cans that need lots of voltage as it's obvious to my ears it doesn't sound right(I have orthos), but I do like the ODAC/O2 with iems and ODAC as my source.  I'm looking for a portable that can do just as well or better the ODAC/O2 combo for iems.  
 
I personally think it's the ODAC that's making the difference.  Which I heard is a simple build using only the required components to implement the DAC.  I believe it's the ESS 9023, not the new popular 9018 which is much more expensive.

 

[jring]

  Ahh yes i had forgotten about that.  I'll refrain from ranting about stupid EU laws since your in Belgium

 
Might i suggest your build your own, buy an encapsulated toroid and put it into a box..

 
Or try head'n'hifi, they're based in switzerland and couldn't care less about EU regulations... you could also just buy their version with 1/4" out and RCA in...
 
Joachim

 

[adydula]

 
Well I am happy to say my ODA is up and functional!!!
 
This is my board that I sent to AGDR for testing the last minute changes to the reduced AC supply and a few other last minute improvements....you can read all the techie details at diyaudio.com

The designer, agdr of this ODA had some last minute concerns with the AC supply voltages and heat dissipation etc as well as a few minor "make it even better" items.

The voltage has ben reduced from 24VAC to 16 VAC. This means that no additional heat sinking will be needed and the unit will not get overly warm, unlike some other headphone amps I have had the you could fry and egg on!

This version of the ODA has a 1/4 jack and a 3.5mm input jack for headphones. It has RCA inputs and outputs. It has a 4 position gain selection switch, a clipping LED indicator, and two power rail LEDS.

The DC offset voltages are down to 2 micro volts on one side and 4 micro volts on the other side or channel.
This is 21 times lower than the original O2 amp.

So I hope to find some time in the next few days to do some serious listening and report on how it sounds compared to the original O2 with several headphones.

I still have to drill out the front panel and get it mounted in its nice shiney RED case!!! LOL.
 

 
 

 
If your at all interested in this ODA version you can contact agdr over at DIYAUDIO.COM.
He also has a website agdraudio.com as well.
 
He is one of the most knowledgeable people I have run into that understands circuit design, audio applications etc...very helpful.
 
Alex

 

[adydula]

In the ODA agdr has used a higher quality jack:
 
"The 3.5mm jacks are higher quality Switchcraft jacks, with actual springs inside and not just springy metal, another thing a lot of folks have posted about (bad jacks)."
 
But with the unit having a 1/4 jack I do not think I will be using the 3.5mm one.
 
Alex
 
Note: It may be possible to replace the 3.mm jack in the O2 with one of these? Will take a look.

 

[SilverEars]

Hi, great job on the build.  Wasn't there an add-on to increase the power supplied to the amp, instead of a brand new board build?  If there is one, I want to try it out for my O2 and my HE-6

 

[Whitecitadel]

  Might i suggest your build your own, buy an encapsulated toroid and put it into a box..

 
+1 on DIY
 
Or buy a spare from head'n'hifi I think they sell them seperate.
 

   
Note: It may be possible to replace the 3.mm jack in the O2 with one of these? Will take a look.

 
You can use any jack with o2 if you mount it on the panel not the board, any board mounted jack would need compatible leg arrangements however. I also think you need an isolated jack otherwise if its metal surround your grounding the signal to the case in more than one location?
Neutrik do a nice one from what I have read, and this is what the "pre-built" providors seem to use in their "desktop" versions on the o2.
 
Without sounding like a head'n'hifi advert they do sell a kit with panels and a 6mm jack and isolated RCA set to convert your o2 to a desktop version.

 

[Solrighal]

Without sounding like a head'n'hifi advert they do sell a kit with panels and a 6mm jack and isolated RCA set to convert your o2 to a desktop version.

I own that version, although I bought mine pre-built. It's an excellent device & a bargain. Particularly if you have the skills to build it yourself.