The New iRiver/Astell & Kern AK100: A High-End DAP
Mar 15, 2013 at 10:29 AM Post #3,241 of 9,165
I want to ask a noob question regarding the 22 ohm out put and I do apologies if it has already been discussed but what kind of negative audible impact should we expect? 


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.
 
Mar 15, 2013 at 10:35 AM Post #3,242 of 9,165
Quote:
Seems like that amping the AK100 is than essential. What amps would you recommend with AK100?

PS:I dont think I will go down the RWAK100 anytime soon, I hope my mid this year we have more reviews. I am sure the prices for the AK100 will reduce in near future. I sort of feel as I type this there is a revision of AK100 taking place some where in korea. 


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... :)
 
Mar 15, 2013 at 2:40 PM Post #3,243 of 9,165
Quote:
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.
 
Mar 15, 2013 at 3:26 PM Post #3,246 of 9,165
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
mad.gif

 
Mar 15, 2013 at 3:46 PM Post #3,247 of 9,165
So basically, when using Ak100 with those IEMs/CIEMs that has about 20 oms impedence, all will lose their bass ?


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.
 
Mar 15, 2013 at 5:02 PM Post #3,248 of 9,165
Quote:
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.

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 ?
 
Mar 15, 2013 at 6:49 PM Post #3,249 of 9,165
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.
 
Mar 15, 2013 at 7:05 PM Post #3,250 of 9,165
Quote:
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.
 
Mar 15, 2013 at 7:18 PM Post #3,251 of 9,165
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.
 
Mar 15, 2013 at 7:43 PM Post #3,253 of 9,165
Quote:
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 a lot.
Finally get the method solve this problem!
 
Mar 15, 2013 at 8:30 PM Post #3,254 of 9,165
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. 
 
Mar 15, 2013 at 9:34 PM Post #3,255 of 9,165
Quote:
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.
 

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