iPod Classic... DAC and output stage info from Vinnie of RWA

[Vinnie R.]

Quote:

Originally Posted by manaox2 /img/forum/go_quote.gif Haha, the money for my iMod and vCap dock went through 3 days before the price drop (the day before the classic was announced). I actually expected the price to go up... Apple showed me they do listen after all. I love my 1st gen shuffle. My next upgrade will be the 160gb classic, I only need to know one thing. [size=medium] Would the 160gb drive work in the 5.5 gen iMod?[/size] If so, it would double the capacity AND increase battery life. 0.02 mw per gb read. This is one highly efficient hard drive.

Hi manaox2,

I need to get my hands on a 160GB drive and try it in my 5.5G iMod.

I read a pretty cool idea here (I forgot who posted this) that one can probably buy a 160GB iPod Classic for just a little more than buying the 160GB drive by itself. So just trade the 80 and 160GB drives between the 5.5G and the 6G. Then I guess you can sell the 80G 6G and that makes the price of the 160GB drive seem like a whole lot less!

Of course, I am only guessing that they will work. I still need to try it

I'll keep you all posted,

Vinnie

 

[manaox2]

Quote:

Originally Posted by Vinnie R. /img/forum/go_quote.gif Hi manaox2, I need to get my hands on a 160GB drive and try it in my 5.5G iMod. I read a pretty cool idea here (I forgot who posted this) that one can probably buy a 160GB iPod Classic for just a little more than buying the 160GB drive by itself. So just trade the 80 and 160GB drives between the 5.5G and the 6G. Then I guess you can sell the 80G 6G and that makes the price of the 160GB drive seem like a whole lot less! Of course, I am only guessing that they will work. I still need to try it I'll keep you all posted, Vinnie

Thanks Vinnie, this has all that has kept me sane knowing that my iMod could still be improved upon to the point of me not having to defend against the classic.

 

[jlingo]

Quote:

Originally Posted by omendelovitz /img/forum/go_quote.gif FWIW, I recently picked up the 4G imod via ebay (-> Vinnie direct -> me), and although I'm liking it a lot and have noticed improvements in SQ, the improvement wasn't the night and day I expected from reviews here on head-fi.

The sound improvement is pretty dramatic, I would say night and day with Ultrasone 9. I think it really depends on your whole system and recording. The higher end your system is perhaps it becomes more senstive in terms of detecting bad source?

 

[me7]

When you say that the iMod sounds warm, do you mean it has a near-perfect frequency response and produces a very natural warm sound, or does it sound like some bass-boost equalizer?

I'm currently looking for a flat-sounding audio player with a good money to value ratio. Can some 6G owners post their expiriences about its "flatness"?

 

[Genetic]

Quote:

Originally Posted by Vinnie R. /img/forum/go_quote.gif I read a pretty cool idea here (I forgot who posted this)....

LOL.....as usual..... I'm the Head-Fi's Rodney Dangerfield (I don't get no respect)....

Amicalement

 

[KB]

Quote:

Originally Posted by Genetic /img/forum/go_quote.gif LOL.....as usual..... I'm the Head-Fi's Rodney Dangerfield (I don't get no respect).... Amicalement

I respect you Dany!!!

Ken

 

[WindowsX]

Vinnie? Have you ever tried modding g6 with g4 or g5.5 imod trick and compare to previous generations in real test? I'm curious to know if adding extra caps (that g6 doesn't really have) can improve sound quality.

 

[Bostonears]

Quote:

Originally Posted by WindowsX /img/forum/go_quote.gif Vinnie? Have you ever tried modding g6 with g4 or g5.5 imod trick and compare to previous generations in real test? I'm curious to know if adding extra caps (that g6 doesn't really have) can improve sound quality.

Have you read the previous 126 posts in this thread?

 

[WindowsX]

I did but he didn't state anything about real experiment.

 

[HeadphoneAddict]

Quote:

Originally Posted by WindowsX /img/forum/go_quote.gif I did but he didn't state anything about real experiment.

He said it isn't worth the time and effort, or money to do the mod on a 6G.

 

[manaox2]

Not to mention it uses a push + pull DAP with everything all inclusive, so there are no capacitors to replace and only internal chip components that would be unbearably painful to mod.

 

[WindowsX]

This is electronic. Adding caps to output stage sure makes sound difference. Without real try, we'll never how it will look like for the real outcome. Some designs in amp stated it doesn't need caps but some are better with caps eventhough it doesn't have to have caps.

 

[manaox2]

Quote:

Originally Posted by WindowsX /img/forum/go_quote.gif This is electronic. Adding caps to output stage sure makes sound difference. Without real try, we'll never how it will look like for the real outcome. Some designs in amp stated it doesn't need caps but some are better with caps eventhough it doesn't have to have caps.

Send me a classic and I'll try it with my vCap dock.

 

[Vinnie R.]

Hey guys,

For the 6G iPod Classic, all that is in the line-out signal path after the Apple CODEC is a tiny surface mount 10-ohm resistor, inductor (for HF noise filtering), and the the board traces that feed down to the dock connector.

I could bypass all of this and hard wire from the dac directly to the line-out using high-quality wire (like the Cardas wire that I use for the 5G/5.5G iMod), but I don't expect nearly the same kind of improvement as the iMod gives for the 4G, 5G/5.5G units. There is no opamp stage to bypass, no crappy coupling caps before and after the opamp stage to bypass, etc.

The "opamp output stage" (push-pull) is already built into the CODEC chip, and since it is running on a split (+/-) supply, there is no dc offset to filter with caps.

WindowsX,

Adding anything in the signal path such as a Vcap may alter the sound (based on the characteristics of the cap), but I believe we are really limited to the sound of this integrated dac + push-pull output stage chip.

The beauty of the 4G and 5G/5.5G iMod (line-out) is that the voltage output of the Wolfson dac was tapped directly and sent out (via a high quality cap), but no push-pull stage or opamp stage of any sort was in the path.

I can see the push-pull output stage as being a good thing for the headphone output (no bass rolloff issues, better drive with low-impedance headphones, etc.) but IMHO, this is not ideal for the line-out.

The only way to really improve the iPod Classic is to tap the native digital signals (I2S) that feed the internal dac and send them out to an external dac of higher quality.

However, just about all external dacs use an SPDIF input, not I2S. I2S is something that you will find *inside* of an external dac, after the SPDIF has been passed through a receiver chip and converted over to I2S to feed the actual dac chip used in the external "dac unit."

As I mentioned eariler, the 6G iPod Classic is a very nice solution for those who are looking to connect directly to headphones, or even for those with a headphone amp. However, the more I listen to it and compare it to my 5.5G iMod + Vcap dock combo, the more I like the 5.5G iMod + Vcap dock combo

Best regards,

Vinnie

 

[trose49]

Quote:

Originally Posted by manaox2 /img/forum/go_quote.gif Send me a classic and I'll try it with my vCap dock.

Im quite sure if it could or should be done Vinnie would have tried it in his V-dock. I quite sure this is not recommended.