The New iRiver AK100: A High-End DAP - Page 217

If depends on the iem in question. You'd have to know what the impedance curve of that IEM looks like to know how it will be impacted. Many dynamic driver IEMs have flat impedance curves and don't change much, if any, with added impedance. Many BA IEMs, especially multi-BA's, have wildly fluctuating impedance curves. It can cause severe treble roll off or spikes and the same for bass.

Innerfidelity has a lot of IEMs measured and includes impedance graphs as well:
http://www.innerfidelity.com/headphone-data-sheet-downloads
Rin's blog is also helpful:
http://rinchoi.blogspot.com/?m=0

Reading an impedance curve can be confusing. Just know if you have a sensitive iem and you see a wild impedance curve, it will be affected. Sometimes the change can be nice, sometimes horrible. That's the over simplified explanation.
Edited by shotgunshane - 3/15/13 at 7:30am

No, it's not.  AK100(stock) with my JH13pro works very well as is,.

IMHO much better than with Vorzuge Pure which I returned  this morning due to muddy humped (at 100-150 hz)  bass,

 and lack of details playback especially  orchestra strings and acoustic guitars.

It's interesting how Vorzuge treats the acoustic instruments - when one guitar is playing you can see hear much of the details,

but if it's a duet or three guitars playing together - they're overlap each other mutually canceling the details  ..

As a former bass /keyboard player I can hear something... :)

JH13 has a 28 oms impedence. That might be the reason why it sounds well with AK100.

However, my To Go! 334 loses its bass when i use AK100.

The TG334 becomes more neutral with added impedance, so yes it looses some bass. Here is it FR with less than 1 ohm, 33 ohm and 100 ohm:

So basically, when using Ak100 with those IEMs/CIEMs that has about 20 oms impedence, all will lose their bass ?

This bloody DAP shuffle play had to be one of the dumbest of all DAP i've used/owned. Keeps playing the same song again and again regardless where I start the selection. For example if I play song A, then it will play song C, D, X, R, so on. If I start by playing song G, it will played the same songs but only different sequence ie. F, X,D, R. On other DAP, if I start on a different songs, it takes a different random play.

 

Very disappointing

Edited by forbigger - 3/15/13 at 12:28pm

It depends on the impedance curve of the iem. Based on most of the BA and multi-BA impedance graphs I've seen I'd say yes, you'll get bass roll off. Sometime moderate, sometimes much greater. You can get a lot of variance in treble response as well.

Edit: it's worth noting that sometimes the change can be agreeable. In the case if the tg334 and w4, some like adding 33ohms or so, to get them closer to a reference frequency response. But others, such as the UE TF10 and many Shure IEMs just sound plain odd or bad with added impedance. That's one of the reasons less than 1 ohms for amplifiers is recommended.
Edited by shotgunshane - 3/15/13 at 12:52pm

How about RWAK100? It's less than one ohms as well.

Which one would you recommend, RWAK100 or adding an amp?

And could you please recommend any amps ?

So what are you going to use with it? If you have higher impedance IEMs and cans (90-300) the regular ak100 is probably fine but if your going to use a lot of sensitive phones under 50 ohms, then I'd want the rwak100.

To me having to carry an amp defeats the purpose of this player. When I owned it, I used it almost exclusively by itself. I did like to use the Continental tube amp with it on occasion but that completely took away its pocket friendly functionality. So if you plan on being mobile and use sensitive phones, the rwak100 is worth it.

I have no earphones higher than 30 ohms. So, yes, they are all low-impedance IEMs including EX1000 (ready to sell), To Go! 334, and upcoming Miracles.

I just recently ordered UM Miracles. But rare people use AK100 with Miracles, so i have no idea what the result is going to be. If Miracles won't sound normal, i probably will go for RWAK100.

However, here is my dilemma. I enjoy my To Go! 334 with AK100, just like what you said it sounds more neutral without overwhelming bass. If i mod AK100 into RWAK100, there is also going to be an uncertain future for To Go! 334 with RWAK100, which might give me more bass. I don't want my To Go! 334 paralyzed by overwhelming bass. So... really hard to make a decision.

Edited by Alias Gu - 3/15/13 at 4:08pm

If you get the rwak100 and find you miss the added impedance on the TG334, you can buy one if these for $18 to add it back:
http://item.mobileweb.ebay.com/viewitem?itemId=290372905689&cmd=VIDESC

You can get them in 22 ohm, 33 ohm and a lot more. Much more elegant way of adding impedance than having it built in the dap where you can't remove it easily.

 

 

Thanks guys for your reply. 

Thanks a lot.

Finally get the method solve this problem!

I have a relative who is an electrical engineer, I spoke to him about doing the 22 Ohm resistor bypassing so hopefully he can figure out which one he needs to bypass.

More importantly I am having an issue with the tagging and cover art as well, seems like the cover art has too be no larger than 400 by 400 pixel. 

Just look at the board. It is easy to spot as they are the last resistors to the ouput on the amp section of the board. You can also double check by going to the headphone socket and do a continuity check and verify you have the right place.