The New iRiver/Astell & Kern AK100: A High-End DAP
Oct 24, 2013 at 2:24 AM Post #7,412 of 9,165
[quotee="Takeanidea" url="/t/630288/the-new-iriver-ak100-a-high-end-dap/7395#post_9916706"]
I don't think it reduces the impedance. I really don't know the science behind them. Ask Rin about how it works.

 
I've got a stock AK100 coming and I have a plug in impedance adapter for my Etymotics ER4Ps that changes them to 100 Ohms. They can be plugged into any IEM. They go loud enough to give me a headache on my Ipod so I'll get back to you on how it changes the sound on my lower Ohm W4rs XBA4ips and Monster Inspirations etc.For me , I have a Slee Voyager Amp and big pockets so I can't lose
Ooh cant wait for your review.. where did u buy the impedamce adaptor?[/quote]


Hi, it was free with my etymotic er4. If you buy the ER4PT you get an adapter that changes the standard ER4P into an ER4S. But what that adapter is doing is simply changing the ER4 from a low ohm to a 100 ohm. I've tried it on all my iems and it works into all my phones amps and Daps so far. I'm quietly confident it'll work on the AK100.
It's available as a spare through etymotic and probably ebay and Amazon etc.
Of course, if it sounds yuk through the AK100 then you'll have wasted your money.
Through the traveller amp double amped from the headphone out of the ipod the ER4 with the adapter is stunning sq by the way.

Sent from my GT-N7100 using Tapatalk
 
Oct 24, 2013 at 11:24 AM Post #7,414 of 9,165
Recently purchased a AK100 from Moon Audio.  I made the jump at Drew's recommendation.  I had time over this past weekend to set-up.
 
My portable rig pairs the AK100 with an RSA SR-71b driving a pair of Westone 4Rs re-cabled with the RSA terminated Silver Dragon v1.0 IEM.  Right angle Oyaide Rhodium plugs terminate a Silver Dragon v1.0 IEM Portable Mini Cable which handles the job of connecting the AK100 and the SR-71b.  Picture attached.

 
 
This is a significant step-up from the iPod Touch 4G/CLAS/SR-72b combo for a few reasons. 
 
First, the front end support for 24/96 and above.  I have listened to several high-rez albums (24/96) on the rig and it is amazing – as close to a great desk top rig as I have heard from a portable rig. 
 
Second, this is a very small package compared to the three piece CLAS set-up I had to carry around.  In fact, the AK100 has a smaller footprint than the SR-71b!  
 
Third, the AK100 supports FLAC and WAV (I know more formats, too, but all my music is either uncompressed, lossless FLAC or WAV) seamlessly – just press play!  Previously on the iPod, I had to install two separate third party apps to play WAV and FLAC formats, respectively.  Each app used the iTunes interface to populate two different libraries on the iPod.  I had conflicts, lock-ups, etc.  No more!
 
While I have just begun to use the AK100, at this point, I could not be happier. 
 
 
Oct 24, 2013 at 4:09 PM Post #7,416 of 9,165
An impedance adapter changes the impedance of your headphones - not the output impedance of the device.  FYI, this will not fix the problem with the output impedance of the AK100.

 


So what is the ohm ratings of the iem's and phones that headfiers have found work well with a stock AK100? Because all of mine can be tried as at least 100 0hm phones. I shall try anyway and see what a real world result brings, it can cause no harm.
Bear in mind I'm no scientist but I know where the University is, I drive past it all the time -:O)
 
Oct 24, 2013 at 5:12 PM Post #7,417 of 9,165
  An impedance adapter changes the impedance of your headphones - not the output impedance of the device.  FYI, this will not fix the problem with the output impedance of the AK100.

 
 
 
  An impedance adapter changes the impedance of your headphones - not the output impedance of the device.  FYI, this will not fix the problem with the output impedance of the AK100.

 


So what is the ohm ratings of the iem's and phones that headfiers have found work well with a stock AK100? Because all of mine can be tried as at least 100 0hm phones. I shall try anyway and see what a real world result brings, it can cause no harm.
Bear in mind I'm no scientist but I know where the University is, I drive past it all the time -:O)

 
The issue with the high output impedance is only because it makes the AK's output impedance so close to (or higher than) many of the earphones out there. If the earphones can be converted to higher impedance this would put more distance between the output impedance and the load which will rectify the problems, however, I am not sure how the adapter actually works. It may be attenuating the volume to be "like a 100ohm" earphone by bleeding off some power rather than actually creating a single load of 100+ ohm.
 
My understanding of these sorts of adapters is that they actually raise the output impedance, not the load impedance (to attenuate volume). Of course, I don't know what wizardry Etymotic might have used so I can't comment on their specific adapter and look forward to Takeanidea's findings.
 
Oct 24, 2013 at 6:30 PM Post #7,418 of 9,165
   
 
 
The issue with the high output impedance is only because it makes the AK's output impedance so close to (or higher than) many of the earphones out there. If the earphones can be converted to higher impedance this would put more distance between the output impedance and the load which will rectify the problems, however, I am not sure how the adapter actually works. It may be attenuating the volume to be "like a 100ohm" earphone by bleeding off some power rather than actually creating a single load of 100+ ohm.
 
My understanding of these sorts of adapters is that they actually raise the output impedance, not the load impedance (to attenuate volume). Of course, I don't know what wizardry Etymotic might have used so I can't comment on their specific adapter and look forward to Takeanidea's findings.

I too am extremely keen to hear the effects of this adapter.
I was considering the RWA Mod however I am funny about sending it overseas with the whole battery issue.
 
This could potentially mitigate the issue with BA Drivers which would be nice.  Upgrade my ASG-1.3's to 2's :D
 
Oct 24, 2013 at 6:45 PM Post #7,419 of 9,165
I sent mine after Vinnie suggested that there's actually no issue. Just declare it as a portable amp or something and if they ask you can say it hasn't got batteries installed. Strangely they don't seem to check!?

That said, it the adapter really works the it'd be my preference too.
 
Oct 24, 2013 at 7:20 PM Post #7,420 of 9,165
I sent mine after Vinnie suggested that there's actually no issue. Just declare it as a portable amp or something and if they ask you can say it hasn't got batteries installed. Strangely they don't seem to check!?



That said, it the adapter really works the it'd be my preference too.

 


The AK100s arrived at my house. I work away so I shall be able to get to grips with it on Saturday. I promise you I will post my findings and I urge you not to buy this adapter til I've tried what it sounds like through a stock AK100 without amping , in the real world. It may be everything sounds great, it may be that the sound is worse or it doesn't go loud enough. I will be as ruthless as my old ears allow.
This is what the etymotic website says:
Convert your ER•4PT earphones to ER•4S earphones with this inline
adapter cable. ER•4PT earphones have approximately 10 dB greater
output at high frequencies and 12 dB greater output at low frequencies
than ER•4S. ER•4S earphones were designed to compensate for the high
frequency emphasis in all CD recordings, in order to provide accurate sound
reproduction. ER•4S earphones can be used with a headphone amplifier
when using low-power portable devices.
TIP: Use the adapter cable with airplane sound systems when
the audio is too loud.

The ER4P is good but to my ears the ER4S is much better in it's reproduction. Interestingly though, I did a sighted test on the ER4S through my ipod unamped and then immediately tried them through my Slee Voyager Amp. The results for me were conclusive; the amped Ipod was far better sound even though the unamped Ipod was perfectly loud enough. It was the same case for every IEM I tried with the adapter or without the adapter.
I'm not saying the AK100 will be the same , obviously it's marketed that it's a cut above an ipod for it's DAC and Amp so it may well produce different results. I just want to state that I do not believe that it is a cut and dry case that this is the best way to get a good sound from the AK100. But I will give it an exhaustive trial and get back to you.

Etymotic sells these resistors for $49. You get them free with an ER4PT and that's a classy IEM you get with an adapter. Of course, it's all useless info to you if it doesn't work with the AK100.
 
Oct 24, 2013 at 8:37 PM Post #7,421 of 9,165
   
 
 
The issue with the high output impedance is only because it makes the AK's output impedance so close to (or higher than) many of the earphones out there. If the earphones can be converted to higher impedance this would put more distance between the output impedance and the load which will rectify the problems, however, I am not sure how the adapter actually works. It may be attenuating the volume to be "like a 100ohm" earphone by bleeding off some power rather than actually creating a single load of 100+ ohm.
 
My understanding of these sorts of adapters is that they actually raise the output impedance, not the load impedance (to attenuate volume). Of course, I don't know what wizardry Etymotic might have used so I can't comment on their specific adapter and look forward to Takeanidea's findings.

The usual recommendation for matching impedances is that the headphones be around 8x that of the output impedance.   If you follow that rule, you would need impedance of your headphones to be 8x22.   If the adapter changes the output impedance to 100 ohms, that would mean that the ideal headphone would have to be 800 ohms.  In either case, if you are a proponent of the 8x rule, there really is no practical solution to this.  Still, 100 is closer to 176, but it might cost in terms of power usage and volume loss.  This might help with the bass dampening issue though.
 
Some headphones have an uneven response to the drop in voltage caused by the high output impedance.  This can also lead to changes in the sound signature.  This is why multiple BA headphones tend to be the poorest matches.  Unfortunately, many of the higher end iems these days have multiple drivers of this type.   This problem can't be fixed by an adapter because you can't add voltage with an adapter and that is only way to guarantee that a headphone will sound the way it was designed (based on expected voltages).  This why you can fix this problem by using an amp though.
 
Oct 25, 2013 at 7:00 PM Post #7,425 of 9,165
Hmmm.... I must admit I'm surprised at my initial results. The adapter undoubtedly cleans up the sound and refines it but in some ways it makes the music a little sterile in comparison.
Also, the favourite iems for this device for me are head and shoulders ahead and they are the x10i.
They're alive in my ears. Without the adapter the live feel of them is astonishing.
The adapter also produces a great sound signature which is clean and probably therefore a less fatiguing one.
The x10i is a single driver iem. I have probably confused those interested now.
My AK100 is not going to be modified. And it will not need amplifying. The sound is all that I wanted it to be. I am happy with that but I can't see me using several extremely good iems.
For my ears there is no need to mod it. X10i's are cheaper than the mod!

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