[kmcdonou]

I am curious how significant of a difference there is playing tunes (lossless or high bitrate MP3s) on an Imod using the ac adapter versus the battery. I want to use Rockbox on my new Imod (haven't got it yet) and I know battery life is not that good.

Since my immediate uses will be in my car or connected to my lowfi basement system, I am wondering if using ac power under these conditions will be significantly noticeable. I am thinking not.

When I get my portable amp and IEMs, I will use battery power for best sound. Yet, even with more revealing gear, how much of an improvement do you get by using battery only? I understand the advantage batteries have in many situations (I own an Ack Dack), but what is the reality with the Ipod. Is the sound of an Imod via the ac adapter still better than a standard Ipod on battery power? Just curious.

 

[kmcdonou]

I can't believe no one's compared the effect of using an Imod, or Ipod for that matter, when using the ac adapter versus the battery. Is the difference significant?

 

[GaryAR]

I haven't compared them with headphones, but I have with my 2-channel rig (iMod -> Red Wine Audio Signature 30 Amp -> Bastanis Prometheus Speakers). This combo is brutally revealing, and with the iPod plugged in it's unlistenable. The highs are harsh and gritty, the soundstage collapses and everything is just wrong. If you need to power the iPod when it's playing, I'd recommend you look into something that uses a battery and not a/c.

Gary

 

[kmcdonou]

Quote:

Originally Posted by GaryAR /img/forum/go_quote.gif I haven't compared them with headphones, but I have with my 2-channel rig (iMod -> Red Wine Audio Signature 30 Amp -> Bastanis Prometheus Speakers). This combo is brutally revealing, and with the iPod plugged in it's unlistenable. The highs are harsh and gritty, the soundstage collapses and everything is just wrong. If you need to power the iPod when it's playing, I'd recommend you look into something that uses a battery and not a/c. Gary

Well that pretty much says it all. Battery it will have to be.

 

[Jon L]

Quote:

Originally Posted by kmcdonou /img/forum/go_quote.gif Well that pretty much says it all. Battery it will have to be.

LOL... Try both. I don't have iMod, but with 4G iPod, I find the AC adapter to sound superior to internal battery. This is when:
iPod->Sik Din lineout->my main 2-channel speaker system.

Caveat: this is with Sik Din lineout adapter powered by hefty firewire cable into AC outlet from a nice power conditioner vs. internal battery. This way, the cleaned AC has significantly more dynamics and detail resolution IMS. The tiny internal iPod battery does NOT equal huge SLA battery with reservoir caps.

 

[Vinnie R.]

Quote:

Originally Posted by kmcdonou /img/forum/go_quote.gif I am curious how significant of a difference there is playing tunes (lossless or high bitrate MP3s) on an Imod using the ac adapter versus the battery. I want to use Rockbox on my new Imod (haven't got it yet) and I know battery life is not that good. Since my immediate uses will be in my car or connected to my lowfi basement system, I am wondering if using ac power under these conditions will be significantly noticeable. I am thinking not. When I get my portable amp and IEMs, I will use battery power for best sound. Yet, even with more revealing gear, how much of an improvement do you get by using battery only? I understand the advantage batteries have in many situations (I own an Ack Dack), but what is the reality with the Ipod. Is the sound of an Imod via the ac adapter still better than a standard Ipod on battery power? Just curious.

Hi kmcdonou,

The stock iPod charger (as well as other aftermarket chargers) are fairly cheap, switch-mode power supplies. They do induce high-frequency noise into the iPod's power input line and ground. You can see this if you use an oscilloscope and zoom in on the voltage rails.... you'll see little "spikes" on the dc rails.

Not only this, but switch-mode power supplies also add noise back onto the AC mains, which can easily couple into other mains power equipment (e.g. a headphone amp or home audio amp that is not powered by battery).


Playing the iPod with its internal battery and disconnecting any power supplies will isolate it, and it gets even better if you amplifier is on battery, as this would result in all equipment running "off-the-grid" and there will no no AC-to-DC conversion taking place...which is never a perfect.

The big question is "will I hear a difference???" I guess how audible this is really depends on the rest of your equipment. I don't want to scare anyone into thinking that using an AC power adapter is a big NO-NO... you might not hear any difference at all, or you may hear enough of an improvement when not using the AC adapter that you will decide to only plug it in when you need to charge (or transfer music). Let your ears be the judge.

Using my Griffin car power supply for my modded iPod, I can really hear high frequency noise of the switching power supply that sounds like static. As soon as I uplug the iPod, the noise is gone.

Quote:

This way, the cleaned AC has significantly more dynamics and detail resolution IMS. The tiny internal iPod battery does NOT equal huge SLA

I posted my opinion about this over here:

http://www.head-fi.org/forums/showpo...2&postcount=17

and here:

http://www.head-fi.org/forums/showpo...3&postcount=29

This is just my humble opinion, and as usual, YMMV.

Happy New Year!

Vinnie