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The New iRiver AK100: A High-End DAP - Page 198

post #2956 of 5017
3/5/13 at 2:58pm
Quote:
Originally Posted by WindowsX View Post

 

This is someone's modded AK100 given to me asking to improve it in a way better than improper mod of by-passing resistor alone. I made some franken adaptors for small tests while waiting for real deal. My theory turned out to be right and thankfully that Dr. Jan Meier already pointed some hints about this out way before I have my hands on AK100 so kudos to him as well. I'd have left this alone like him if no one dared to give me one for free to mod this :D

Ears dont lie...audibly speaking the mod is very recognizable improvmement...now I cant speak to the technical aspect of it...re: if the unit melts out in a month of heavy high volume etc.  I have been using the RWAK with my HD800's via the RS Intruder...SQ is better than some of the full size systems I've heard via my HD800's.

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post #2957 of 5017
3/5/13 at 3:15pm
Quote:
Originally Posted by toads View Post

 

Not sure if english is your native tongue but you're coming off rather rude and arrogant...I'd suggest you practice a bit of respect when just popping into a near 200 page thread for the first time dropping off your criticisms for all to behold...

 

I certainly don't claim to know much beyond the very basics...but sorry, what is your training, credentials, background etc...?

 

i don't want to make the assumption that you're some sort of DIY, name dropping, solder burner making wild claims...lol

 

 

At least try to respect people posting intellectual information and try to focus on making things better as I also want to make AK100 better than original and try to help improving modding methodology as much as I can.


Edited by WindowsX - 3/5/13 at 3:25pm
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post #2958 of 5017
3/5/13 at 3:16pm

Your guys' argument is really unnecessary.

Why not just get rid of this topic?

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post #2959 of 5017
3/5/13 at 3:25pm
Quote:
Originally Posted by Alias Gu View Post

Your guys' argument is really unnecessary.

Why not just get rid of this topic?

 

I agree thanks. Sinking is not good option. Edited.


Edited by WindowsX - 3/5/13 at 3:30pm
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post #2960 of 5017
3/5/13 at 3:32pm
Quote:
Originally Posted by WindowsX View Post

 

1. Originally, the true reason why iRiver added 22 ohm resistor was because output stage couldn't handle stable current at 0 ohm. Not many equipments can actually drive high current at 0 ohm and most preamps in hifi market won't go natively as low as 0 ohm. 22 ohm was added as safety resistor so that output stage won't be damaged from high current drainage.

 

2. Along with safety resistor, I believe iRiver also made some other changes in circuit design to handle with 22 ohm so that it can produce neutral harmonics with better SPL/THD calibration. Forcefully removing safety resistor also made drastic changes in sound reproduction and mostly not in proper improvements. From what I observed, it has poor 3D image presentation and punching of dynamics wasn't no longer strong or bold enough. PRaT isn't properly fine-tuned with different impedance load. I setup tons of decent sources from Esoteric/Emm Labs/others with proper PRaT fine-tuning so I daresay that mod screwed this up and I'm trying to fix it here.

 

3. By saying improper mod, I didn't mean it's all bad and no good. It's just not completely good and I think it's possible to make this more safe and better. Maybe I used the wrong word sorry. I should have said it's incomplete mod. Dr. Jan Meier may have something in his head to make it more completed than it currently is. Well, I'm not experts in this field and can't read much from seeing bare board so I'm not daring enough to say what is actually completed.

 

WindowsX,

 

1) Let's first clear the air about "0-ohm."  We all know there is no such thing as there is going to be some resistance in the circuit.  So when I say "0-ohm" or "bypass the 22-ohm resistors," please make sure you know I really mean "less than 1 ohm."  

 

I have tested the RWAK100 to be totally stable after bypassing the 22-ohm resistors.  After bypassing of the 22-ohm resistors, there isn't a safety issue even if the output was shorted.  How do I know this?  I tested it!  The output stage does not get damaged.  Sure - this is not recommended and the output FETs get hot, but they don't fail. 

 

How many headphone amp designers do you know who are putting 22-ohm resistors on the output of their amps for "safety?"  

 

2) Do you really believe this is true?  I do not see any evidence of this being true when tracing out the circuit.  The 22-ohm output resistors are unnecessary and bypassing them only IMPROVES the presentation.  With the resistors in the circuit, the dynamics and PRaT you speak of are inferior (especially with lower impedance headphones or IEMs).  You can easily hear this if you put in a DPST switch that simply shorts the resistors (bypassing them), or leaves them alone.  Do this and listen as you switch on the fly - it is very obvious that bypassing the 22-ohms is an improvement all around - nothing about the music suffers.   The sound opens up with them bypassed and there is more life to the sound.  

 

Have you tried this and listened to compare?   

 

 

3) But is already is safe, and bypassing is the cleanest way.  Adding capacitors in series to the output (as your picture shows) when they are not needed will only add their coloration to the sound (for better or worse).  Anyone can play with adding caps in series with the output, but it doesn't make it a "complete mod."   The mod is already complete as is.

 

And you say:

 

Quote:
I setup tons of decent sources from Esoteric/Emm Labs/others with proper PRaT fine-tuning so I daresay that mod screwed this up and I'm trying to fix it here.

 

and then you say:

 

 

 

Quote:
Well, I'm not experts in this field and can't read much from seeing bare board so I'm not daring enough to say what is actually completed.

 

Unless I am not understanding you, these are somewhat conflicting statements.   You are daring so say the mod screws up the sound and you are trying to fix it, but you are not daring enough to say what you are doing instead and how it is better?

 

 

And regarding:

 

 

Quote:
If AK100 can natively run 0 ohm output driving any portable headphones without trouble at all, the only reason to cap resistor is to make it sounds worse purposely so they can make a new product sounding better. Otherwise, it's plainly gimmick with pros and hidden cons hoping you won't findout or the makers aren't aware of that yet.

 

If you've read through this long thread, you'll see people posting replies to their questions/concerns from iRiver, and how iRiver has changed their story a few times regarding the 22-ohm out - so who really knows what they were thinking?  I makes no difference - adding unneeded 22-ohm resistors in series with the output will only make it perform worse with headphones or IEMS (again, especially the lower impedance ones).  A complex solution is not needed.  I bypass them, and while I was at it, I bypassed the traces and connector on the motherboard that connects to the headphone board, and hard-wired from the output FETs to the pins of the headphone jack (a shorter, cleaner connection is a good thing).

 

Best regards,

 

Vinnie

 

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post #2961 of 5017
3/5/13 at 4:27pm
popcorn.gif
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post #2962 of 5017
3/5/13 at 4:36pm
Quote:
Originally Posted by Alias Gu View Post

Your guys' argument is really unnecessary.

Why not just get rid of this topic?

 

 

Yup...trolls are the sux...lol

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post #2963 of 5017
3/5/13 at 7:06pm

Quote:

Originally Posted by Vinnie R. View Post

WindowsX,

 

1) Let's first clear the air about "0-ohm."  We all know there is no such thing as there is going to be some resistance in the circuit.  So when I say "0-ohm" or "bypass the 22-ohm resistors," please make sure you know I really mean "less than 1 ohm."  

 

I have tested the RWAK100 to be totally stable after bypassing the 22-ohm resistors.  After bypassing of the 22-ohm resistors, there isn't a safety issue even if the output was shorted.  How do I know this?  I tested it!  The output stage does not get damaged.  Sure - this is not recommended and the output FETs get hot, but they don't fail.

That is good to know. 

 

It would be nice to know their thinking on the addition of the 22ohm resistor. Seems so counterproductive to the essence of the product.

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post #2964 of 5017
3/5/13 at 7:52pm

Hi guys,

now I'm looking for a carrying case for AK100+ IEMs. What do you use?

I know that some OtterBox and Pelican cases would fit, but i don't know the number of the models:(

Can anyone help me with them, please?

Or maybe somebody uses some other case like that, any recommendations would be much appreciated...

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post #2965 of 5017
3/5/13 at 8:31pm
Quote:
Originally Posted by aqtaket View Post

Hi guys,
now I'm looking for a carrying case for AK100+ IEMs. What do you use?
I know that some OtterBox and Pelican cases would fit, but i don't know the number of the models:(
Can anyone help me with them, please?
Or maybe somebody uses some other case like that, any recommendations would be much appreciated...

A bit spendy, but its nice, works perfectly for me.

http://www.ebay.com/itm/iRiver-Astell-Kern-AK100-Genuine-Italian-Leather-Case-2-Color-Black-Brown-/290848643599?pt=LH_DefaultDomain_0&var=&hash=item43b7ee1a0f
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post #2966 of 5017
3/5/13 at 8:34pm
Quote:
Originally Posted by aqtaket View Post

Hi guys,

now I'm looking for a carrying case for AK100+ IEMs. What do you use?

I know that some OtterBox and Pelican cases would fit, but i don't know the number of the models:(

Can anyone help me with them, please?

Or maybe somebody uses some other case like that, any recommendations would be much appreciated...


I ordered this one off eBay>>>>> http://www.ebay.com/itm/290850351685?var=590100481667&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

Processed By eBay with ImageMagick, R1.1.1.M2a

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post #2967 of 5017
3/5/13 at 9:59pm
I bought mine from this site http://item.mobileweb.ebay.co.uk/viewitem?itemId=290850351685. As i live in overseas..the final cost is painfull actually. But no choice. I have it without the strap. Because mainly i am going to stack with amp anyway.
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post #2968 of 5017
3/5/13 at 10:46pm

Dear Vinnie

 

 

"1) Let's first clear the air about "0-ohm."  We all know there is no such thing as there is going to be some resistance in the circuit.  So when I say "0-ohm" or "bypass the 22-ohm resistors," please make sure you know I really mean "less than 1 ohm."  
 
I have tested the RWAK100 to be totally stable after bypassing the 22-ohm resistors.  After bypassing of the 22-ohm resistors, there isn't a safety issue even if the output was shorted.  How do I know this?  I tested it!  The output stage does not get damaged.  Sure - this is not recommended and the output FETs get hot, but they don't fail. 
 
How many headphone amp designers do you know who are putting 22-ohm resistors on the output of their amps for "safety?" "
 
I apologize for making improper short abbreviation term like 0 ohm as to shorten < 1 ohm output impedance. If you read my earlier posts, I noted Dr. Jan Meier's products for using < 1 ohm output impedance as well. For FET you said tested and it's OK. Sure it was hotter but not fail like you said, did you test this at highest current drainage level for long run like 200hrs continuous? Even if you put some power hungry phones and run at 100% volume for days and it didn't fail. It doesn't mean there's no damage to FET at all. If FET were to be worn out for x days, I'm sure doing this won't exactly last for the same time if you keep using it at its extreme condition having high current surge frequently with high dynamic swing track.
 
"2) Do you really believe this is true?  I do not see any evidence of this being true when tracing out the circuit.  The 22-ohm output resistors are unnecessary and bypassing them only IMPROVES the presentation.  With the resistors in the circuit, the dynamics and PRaT you speak of are inferior (especially with lower impedance headphones or IEMs).  You can easily hear this if you put in a DPST switch that simply shorts the resistors (bypassing them), or leaves them alone.  Do this and listen as you switch on the fly - it is very obvious that bypassing the 22-ohms is an improvement all around - nothing about the music suffers.   The sound opens up with them bypassed and there is more life to the sound.  
 
Have you tried this and listened to compare?  "
 
I listened to and compared. I didn't say this is a bad mod not even once. How can you be sure that they only add 22 ohm resistor to reduce load of impedance? by-passing it has pros and its cons. Overall sound performance surely is improved having lower output impedance but its stability doesn't improve from what I heard myself. I found tons of good ears people including me complaining they sound at the same level, no depth, poor imaging and you can't feel much of the slam and impact. It's more revealing and linear with cleaner sound so fixing its cons would make this perfect.

 

"3) But is already is safe, and bypassing is the cleanest way.  Adding capacitors in series to the output (as your picture shows) when they are not needed will only add their coloration to the sound (for better or worse).  Anyone can play with adding caps in series with the output, but it doesn't make it a "complete mod."   The mod is already complete as is.

 
And you say:
 
Quote:
I setup tons of decent sources from Esoteric/Emm Labs/others with proper PRaT fine-tuning so I daresay that mod screwed this up and I'm trying to fix it here.
 
and then you say:
 
 
 
Quote:
Well, I'm not experts in this field and can't read much from seeing bare board so I'm not daring enough to say what is actually completed.
 
Unless I am not understanding you, these are somewhat conflicting statements.   You are daring so say the mod screws up the sound and you are trying to fix it, but you are not daring enough to say what you are doing instead and how it is better?"
 
Adding output coupling capacitor also has its pros and cons just like resistor by-passing mod. You have your own design and philosophy believing this is the best way why others like Jan Meier here may have different approach from you. caps has its character for colorization and practically make it less rock solid for fastest speed. But your current mod is way too fast for device to handle causing imaging and pace caused by too fast PRaT speed and balance. Add c output can help balancing signal current flow speed and prevent surge from high current drain making FET works less extreme and prolong its lifetime. C output coupling also have other pros for reducing background noise/THD effects/and vibration influence.
 
For last part I'm saying to admit that I don't know enough of engineering to design and make my own like that so I won't say what will be better between Vinnie and Meier's approach. But I also have listening experiences in this field first hand. I heard many world-class super highend equipments and they're generous enough to show me what's inside and how things work internally. Why < 1 ohm impedance is good and what's difficult to make a very good ones.
 
Let me say this clear again that it's not a bad mod but there're parts working better and some parts having problems. Even original design has some good reason to do that and bad reason why it shouldn't be like that.
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post #2969 of 5017
3/5/13 at 11:53pm

Guys, thanks a lot, but I already have this leather case:)))

Maybe I explained wrong, I need not a carrying, but a transportation case - the AK100 (preferrably in the leather case) and IEMs should fit into it.

I hope some OtterBox and Pelican cases would do (like the ones Suyama and Heir Audio suggest with their IEMs), but I don't know the model numbers:(


Edited by aqtaket - 3/5/13 at 11:54pm
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post #2970 of 5017
3/6/13 at 12:29am
Quote:
Originally Posted by aqtaket View Post

Hi guys,

now I'm looking for a carrying case for AK100+ IEMs. What do you use?

I know that some OtterBox and Pelican cases would fit, but i don't know the number of the models:(

Can anyone help me with them, please?

Or maybe somebody uses some other case like that, any recommendations would be much appreciated..

I prefer a holster over cases.   Unfortunately, there isn't a holster available yet - as far as I know.  So, I improvised and bought a cheapo cellphone holster from the local dollartree.  I cut out slots for the volume knob and the buttons.  This cheap case is actually easier to customize than a more expensive one made from nylon web.  This one is made out of some rubber fabric and can be cut by a pair of scissors.  My cheapo mod!  Price: $1.

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