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The New iRiver AK100: A High-End DAP - Page 204

post #3046 of 8363

After leaving maximum volume with headphones on for a night, it still works without getting short circuit. I tried with loudspeakers system again and things seem to improve a lot. I couldn't hear weird sounds at all now. Maybe it's cellular problems like zerodeefex's case. However, I still can hear little distortion when dynamics getting high at mid/low frequencies sometimes though. It could be problem with modded unit I have myself or problems with connected devices so I'll investigate more.

 

It's not like I don't trust Vinnie but we all know there's risks after modding like iRiver said. It should work without serious problems for most of the cases but being safe before sorry isn't always bad choice. Maybe I should buy RWAK100 and test on that unit myself.


Edited by WindowsX - 3/7/13 at 10:42pm
post #3047 of 8363

Ya  think so?  Yeah, maybe it's a good idea for you to buy the device that you've tried like hell to raise a panic over.  

 

Maybe, i don't know, you could actually listen to it for a couple of minutes before you impugn the character of one of the most respected engineers in the Hi-Fi world?

 

Nah!  That's crazy talk!

 

Why don't you save yourself some money, and just keep on talking bat **** crazy crap about **** you have no idea about?  Keep warning us about oscillations, gawd knows we love that ****!

post #3048 of 8363

Seems like you're not used to constructive debate...

post #3049 of 8363
Quote:
Originally Posted by WindowsX View Post

Seems like you're not used to constructive debate...

 

 

Oh hell no, I love constructive debate!  Tell us once more how perilous oscillations may be, then mention once again that you're only now considering actually trying out the device you've been criticizing...  I love that part!

post #3050 of 8363

Then put off sarcasm and bad remarks while making one. I don't recall confirming it has oscillations. I just doubted it and that's very different from confirming it. Now It's clear that it doesn't have oscillations but current problems could lie elsewhere like fet output couldn't handle such load with some devices.

 

And I don't favor paying another $1k that I can't be sure it's safe while I can test the similar  under $30 topping existing AK100. If something goes wrong, $30 is the price easily worth for paying to test and fix it but not $1k. If it all goes well, $1k is worth for buying for what I trusted now.


Edited by WindowsX - 3/7/13 at 11:19pm
post #3051 of 8363

While sitting at my bored and cold office, waiting for release for weekend, this thread is really amusing, GJ keep going popcorn.gif

post #3052 of 8363
Quote:
Originally Posted by WindowsX View Post

Then put off sarcasm and bad remarks while making one. I don't recall confirming it has oscillations. I just doubted it and that's very different from confirming it. Now It's clear that it doesn't have oscillations but current problems could lie elsewhere like fet output couldn't handle such load with some devices.

 

 

You forgot to mention how a nuclear explosion is also possible...

post #3053 of 8363

I've had Vinnie's RWAK100 when it was first announced on his FB page (received maybe late December?) that he was going to sell modded AK100's. It's my primary DAP since.Sadly I don't know what dB I'm listening to but put it through an honorary 72 hr burn in at max volume with 24k resistors courtesy of Vinnie.

 

Thereafter I've probably used the RWAK100 with my headphones at volume setting 45 - 63 (depending on headphone). So far I've not had any problems with the RWAK100 mod. I have had non-modded issues such as my microSD card losing its index and therefore access to tracks but that's just re-indexing.

 

As for what WindowsX is posting, personally for me, I actually find it fascinating due to my lack of knowledge of audio electronics. Reading beyond the writing tones and writing styles, and just getting into the actual technical content, I personally find it interesting. Maybe the AK100 thread isn't the appropriate thread to talk about theory and theoretical limits, and when the theoretical limit becomes a practical limit.

 

May I suggest this conversation continue on the Sound Science section?

post #3054 of 8363
Quote:
Originally Posted by AnakChan View Post

 

 

As for what WindowsX is posting, personally for me, I actually find it fascinating due to my lack of knowledge of audio electronics. Reading beyond the writing tones and writing styles, and just getting into the actual technical content, I personally find it interesting. Maybe the AK100 thread isn't the appropriate thread to talk about theory and theoretical limits, and when the theoretical limit becomes a practical limit.

 

 

 

That's quite a coincidence, I'm fairly certain that WindowsX finds it fascinating because of HIS lack of knowledge of audio electronics!

post #3055 of 8363
Ok, back to the AK100. AnakChan, you've mention that Tera Player is on another level. Can you explain the weakness of the RWAK100 compared to the Tera Player? I'm really curious about it. Thanks.
post #3056 of 8363
Quote:
Originally Posted by nelamvr6 View Post

 

 

That's quite a coincidence, I'm fairly certain that WindowsX finds it fascinating because of HIS lack of knowledge of audio electronics!

 

Wow. That's rich...and you said you love constructive debate.

 

Put trolling aside, I know many technicians having their own concern about this mod reading this thread but decided to keep silent. Same things happening in place I live right now. I won't say much as it doesn't really bother common 32 ohm portable headphones at moderated volume but connecting as lineout may not be wise choice without resistor.


Edited by WindowsX - 3/8/13 at 1:39am
post #3057 of 8363
Guys, no need to jump for the jugular...topic can easily be continued in other sub-sections of this forum. I do a lot of listening which is what most of my reviews are based on but my theoretical audio electronics knowledge is extremely weak (but I'm not exactly stupid either ;-)). I see a few members here who are having differing opposing theoretical discussions which is good, but I also speculate a lot of fanboy campers who may or may not even understand the discussion but being vocal here. Again, Maybe this thread is not the right thread for this kind of discussion and can be moved to Sound Science.
Quote:
Originally Posted by Jazzyfi View Post

Ok, back to the AK100. AnakChan, you've mention that Tera Player is on another level. Can you explain the weakness of the RWAK100 compared to the Tera Player? I'm really curious about it. Thanks.

Keeping in mind this is preferential, & I have only listened to the Tera twice but it's enough to grab my attention. I find it to be a rich, smooth and very analogue (vinyl-like) sound.
post #3058 of 8363
Quote:
Originally Posted by WindowsX View Post

Folks. I have good news and bad news about RWAK100 mod after researching with a few technicians and did some research regarding its output stage.

 

Good news: If oscillation doesn't occur with current setup, it most likely will not happen after long usage.

Bad news: What iRiver engineer actually did after FET in output stage could possibly be low pass filter for cutting excessive high frequency. You have resistor in serial and capacitor in parallel. Removing resistor will most likely affect how they configure the filter of output stage as it will remain with capacitor in parallel alone as load capacitance.

 

If what I found are true, we need to confirm whether this is proper design to improve output stage. Knowing FET part number would be a great help as no one uncovered this so far. If it's not proper design, modifying output stage to more generic and more power like replacing stock 22 ohm resistor with better specs at 10 ohm might help. I haven't checked capacitor values yet so it may need to be increased a bit more after lowering resistor.

 

I hope removing resistor will not affect too much for driving headphones in bad ways. I'm not sure how it'll be like with amplifiers though. I doubt removing r will be wise choice with amps as resistor seems to act like feedback control. Dang.....the more I found the more I'm confused. How could this single resistor could possibly do so much. Let me list what this resistor could possibly do.

 

1. FET protection circuit

2. oscillation prevention

3. Increasing output impedance

4. low pass filter incombination with capacitor in parallel

5. current feedback control

There is no series cap in parallel to a resistor as it would indicate a low slope HIGH pass. If there is a resistor in series on the pos with a cap across the output to neg. it would be a low slope low pass but removing the resistor would only make that slope 6db per octave (steeper). Unless the amp is less stable driving that very minor capacitance without the resistor, it would have less ultrasonic high frequency, not more which usually means less ringing. I think you're looking for issues and leading techs and us into your suppositions. If you wanted the circuit to still have the same slope, you could leave the resistor and jump the ourput like the 2nd fig instead of the first as now. I doubt it will matter but something Vinnie could do easily enough. If the cap is befpre the resistor things are even less affected by it's removal and the filter is intact. If Vinnie jumps from before the resistor to the output without it connected to the remaing track in any way, the Cap is gone as well and there's no roll at all.

 

 

 

The 2nd would behave slightly differently than stock into a real load but should be in the ballpark for anything of reasonable impedance. Personally, I would have done it like the second just to be sure something I couldn't easily measure wasn't getting missed. It's out of circuit within the audio band but still damps ultrasonics.

 

Non techs shouldn't try to understand circuits and evaluate from a technical standpoint without a better understanding or the actual topology to investigate. This unit is not for you. Look elsewhere.


Edited by goodvibes - 3/8/13 at 8:25am
post #3059 of 8363
Quote:
Originally Posted by zerodeefex View Post

Anyone get random pops/crackles with their unit? My RWAK100 does it with various headphones seemingly at random.

Edit:too close to my tablet w/cellular radio :-)

No pops and cracks here...using the RWAK>>Intruder>>HD800's   The best can broughtout  in this puppy when listening to classical and instrumentals...love the combo!!

post #3060 of 8363

FTFY....

 

Quote:
Originally Posted by WindowsX View Post

Seems like you're not used to my offensive, inflammatory, speculative and often irrational suppositions...

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