O2 AMP + ODAC - Page 14

Guys,about the ferrite question\problem.

As i wrote above i did ordered an Odac literally one month ago;does it came already with the "ferrite" change or i have to find out IF i have the same problem of some of us and then send back the unit the them modify my ODac?I though here i would get a quicker response,and i think i have already bore Mr.John Seaber with a lot of questions

Grateful

If you ordered it from JDSLabs it should include a USB cable with a ferrite bead.

 

I think the '"ferrite" change" you're describing is an internal change in JDS Labs' C421 amplifier.

 

The ODAC has an external ferrite on its stock USB cable.

This kind of misrepresentation is really quite irritating. It's not 'good for the price': the whole point of the O2/ODAC is a demonstration that perfect audio reproduction is not very expensive. It's not good for the price: it's both cheap and priceless.

 

Thanks folks,i can see now,in the case of the ODac is the cable with that kind of cylindrical piece plastic covered in some place between both end of it.Just simple as that....

As it happens there is a ferrite on the ODAC itself. There was a note by the designer that the production ODACs had a larger one than the final proof version though functionality was the same. In all likelihood you don't need a ferrite on the US cable.

Hey guys. This is a question just about the O2. Hope you don't mind. 

 

I've got a Xonar Essence STX. Not ready to upgrade to a different DAC yet, but my main phones are all fairly low ohm: SR225i (32 ohm), A900x (40 ohm), HFI-780 (35 ohm). Do you think I would benefit from using the O2 with the STX? The STX is only rated down to 10 ohms. Since my desktop rig has an HK 3390 stereo receiver plugged up to the l/r line out on the Xonar (for my passive bookshelf speakers), I would either connect the O2 to the headphone out on the STX or the tape out on the 3390. 

 

Now I've tried hooking my E17 up to the headphone out on the STX, and I feel like I can hear a positive difference with the Grados, but I'm not sure. So thought it best to check whether or not an O2 kind of upgrade would be an audible improvement. 

 

Thanks for any thoughts. 

 

I think there's some misunderstanding for what the Essence STX is rated for, or what the 10 number comes from.  Actually, who cares what it's rated for?  It has some kind of electronics that can be used to power headphones—let's look at how that does.

 

By all indications, the Essence STX has some kind of competent TPA6120-based headphone amplifier circuit (also used in FiiO E9 and some others, but the STX has lower noise I think), so that can power pretty much any typical headphone very loud with minimal distortion and problems, except for one thing.  It has around 10 ohms output impedance.  Effectively, you can think of it as there being 10 ohms between its output and any headphones you connect to it, which is a bad thing for some headphones and is generally more of a problem the lower the impedance of the headphones (imagine:  10 ohms is significant compared to 30 ohms but not really so significant when compared to 600 ohms).

 

So there are some headphones where the O2 should be a little better than the STX, in a non-trivial way.  For these, the O2 should probably sound more like the E17 does, since the O2 and E17 have lower output impedance.  For others (most everything? especially among full-size headphones), it should be pretty much the same, or at most just marginally different.

 

For those headphones, I'd consider just using the E17.  That said, those headphones have low impedance but mostly constant impedance across frequency, so it probably doesn't matter much.  If you end up with some high-impedance, lower-sensitivity headphones that are too quiet for the E17, run them from the Essence STX.  It should do a great job with those.

 

Given what you have, don't bother with the O2 unless you just want a shiny new box.

 

Thanks. Yeah. I dont' keep the E17 with my home office setup with the STX where I do most of my serious listening. It's normally in my workplace office with headphones I keep there to use with my laptop, which definitely needs the E17 more 

 

So I guess maybe the O2 would be some help, then? 

 

It could  help some small amount, sure.  I would still recommend saving the money, to either pocket, save for new headphones, or whatever else.

 

If you got certain IEMs or Sennheiser HD 5x8 series, or some other certain headphones, I would think there should be a little more difference—actually, a really big difference for some IEMs.  As it is, I wouldn't chase the small (miniscule?) stuff, but you're free to do if you want.

 

I've got some 16 ohm IEMs, but I don't use them with my desktop setup. 

 

At this point, I won't be buying any new headphones for awhile. So that's why I was looking to improve the response of the ones I have. Although if it's that minuscule a difference, does seem better not to spend the money. 

Just got the O2/ODAC, it sound really transparent and powerfull for such a small box!
 

Has anyone tried the O2 (with which gain, 6.5x or something else?) with any 600ohm headphones? Specifically the DT-880?

 

I'm interested in using it but would like to know if it has the voltage swing to drive it properly

 

I have a 32-Ohm Beyer, so I haven't tried this myself. From the designer's blog.

 

The DT880-600 needs over 5 Vrms to play reasonably loudly with all types of music. That's 14 volts peak-to-peak a [sic] most popular portable amps, and even many home sources, cannot manage that much output.

The O2 and ODA, however, both output over 5 Vrms and work fine with the DT880-600. How much gain you need comes down to the source you're using.

Promising! Thank you for that info.