I think a lot of people haven't run their board to cut off. I built one, and my friend built one. I haven't run mine to dead battery yet but he has and his does the oscillation.
@qusp that is a valid point although it's not something I've had much trouble with using decent audio gear. I've never heard any noises from my unbalanced O2 connected to either my unbalanced iPod Touch or Sansa Clip+ along with the unbalanced (albeit short) cable connecting them. It has a lot to do with the PC board layouts in the devices. Even a fully balanced device can have loop areas that are susceptible to noise pickup if the layout is not fully symmetrical with respect to not just component placement but ground currents, etc.
RocketScientist;2796834 @Balanced Audio said:
I agree except in cases where one wants to drive an inefficient headphone with an IC opamps based amplifier as a budget solution, where 7Vrms just doesn't cut it as outlined in your "power blog", in that case balanced/bridged is the only option short of a discrete opamp where +-30V rails can be handled. Its a case of economics though, you are much better served with a SE discrete opamp (like the Betta 22/Dynahi) running +_30V rails, than a balanced IC opamp based amp running balanced (one is just a lot cheaper to implement.)
For modern phones and modern DAC's its best to properly transform the differential dac ouputs to single ended in order to get the CMRR required for S-D DAC's to come close to their datasheet specs. Whether this should be done in the DAC or the amp is debatable, but I agree fully, waiting to do it at the headphone is crazy.
But certainly no one would advocate not utilizing the balanced output of a S-D dac chip and just leaving one output pin in limbo as I have seen done in many compromised designs (ala DLIII). I really don't think you aren't advocated this practice?
I am convinced that the whole balanced headphone trend originated with weak SS amps, adding 2 channels gave from 2 to 4x the power and the folks that didn't understand what was going on saw the different headphone jacks and viola the balanced headphone became a must have.
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@regal, agreed. That's one of the benefits of bridged outputs when power supply rail voltage is limited. I talk about that in the 3 Channel article. But there just are not many current headphones on the market than need more than the 7 - 9 Vrms you can get from 12V or 15V power supply rails with a better performing conventional "unbalanced" amp.
Ya think . . . maybe ? ? ?
Just note the behavior in the user's manual as the "low battery warning" and be done with it.
Agreed, but they are out there, especially with you beautiful expose' of power requirements for high dynamic range recordings, and those when one encounters when monitoring/mixing raw recordings. But for 99.9% of younger buyers/non-heavy sound reproduction engineers or enthusiasts 7-9vrms is plenty.
Any chance of supporting coax or optical? I typically use a CD player at home rather than a laptop for the music.
Thanks Sofaspud and Dewardh. I keep trying to point that out. Hopefully we can move on to more productive O2 topics than how polite the amp is some circumstance with unusably low batteries.
I am curious if anyone has tried driving "difficult" headphones with their O2? While I've done all the math for some obvious candidates like the Beyer DT800-600, Audeze LCD-2, some HiFiMan planars, certain power hungry AKG models, etc. it's useful to get real-world reports from those who actually own power, voltage, and/or current hungry headphones.
@timjthomas, sorry but there are currently no plans for S/PDIF as it would add significant expense that few will use. The analog output of your CD player may well be just as good. See the Matrix Audio Challenge--they compare a cheapo bargain Sony CD player's analog output to a high-end Wadia and nobody could hear the difference.
I am curious if anyone has tried driving "difficult" headphones with their O2? While I've done all the math for some obvious candidates like the Beyer DT800-600, Audeze LCD-2, some HiFiMan planars, certain power hungry AKG models, etc. it's useful to get real-world reports from those who actually own power, voltage, and/or current hungry headphones.
@timjthomas, sorry but there are currently no plans for S/PDIF as it would add significant expense that few will use. The analog output of your CD player may well be just as good. See the Matrix Audio Challenge--they compare a cheapo bargain Sony CD player's analog output to a high-end Wadia and nobody could hear the difference.
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Well that is good to know! Thanks!!
I have all of my CDs ripped (both FLAC and mp3), but have yet to really here a decent sound out of a PC -- as compared to a simple CD player. This is probably due to the "poor PC setup" we have at work. (Just to clarify, I am not stating that PC Audio is bad, only that I haven't gotten it "good yet.")
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@timjthomas, PC audio can sound just just like CD audio (I've done my own blind tests). I talk about that more in CD's Are So 1980's. If anything, PC audio has some potential to sound better.
Evidence of no difference is not proof of equality. That is a logical fallacy.
I think it's fair to say "PC audio can sound just just like CD audio." I'm not saying it always sounds the same. But to a great many listeners, in blind tests, they can't tell them apart.
And an entirely objective technical argument can be made the exact same bitstream can be made to appear in both cases at the input to the DAC itself. This can indeed be proven objectively.
I do not doubt you at all. At work I'm quite certain it is not possible as our IT group has the PCs tied down such that I can not install any SW or set things up properly.
At home I'm sure I could. However, I like being able to select a CD or LP and read the liner notes while listening to the music. (Not claiming any of it sounds better -- only that there are really no liner notes while listening on the PC.) I also find that if I have the PC up, I end up surfing the web instead of paying attention to the music.
Not sure what happened to my post, but I do believe that PC audio can sound as good as CD. What I miss with PC audio, is the selection of the music -- either CD or LP and reading the liner notes while listening. I listen to a lot of classical, so the CDs & LPs always come with some interesting reading.
I find that if I listen to the PC, I end up surfing the web instead of listening to the music.
I like the process of walking up to my CD (or LP) selection and deciding what to listen to.
Sorry for the "double post."
I find that if I listen to the PC, I end up surfing the web instead of listening to the music.
I like the process of walking up to my CD (or LP) selection and deciding what to listen to.
Sorry for the "double post."
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My PC sounds better when I have a high impendance device plugged into it. The hiss goes away and some more details reveal themselves. The best is when I have my quality DAC and Amp plugged into my PC. It's so much better that way. Every CD player I've ever had has been prone to interference noise, and some PC audio has been that way, but not with my DAC/Amp combo.
I've played with "enhancement" software, but there are always trade-offs and I usually don't play that game. When I'm in the mood I like SRS Audio Essentials best.
I've played with "enhancement" software, but there are always trade-offs and I usually don't play that game. When I'm in the mood I like SRS Audio Essentials best.
That sounds like a good idea! (I guess I'm just old fashioned
)So, to get the thread back on board, any idea on when the desktop version with DAC would be "ready?"