[twister6]

  Hope it's not to late to update this. Just got it in today (I will be reviewing it at HFN). It is a very good sounding player. I've only had it behind some of my favourite 16 and 24 bit files for about an hour. The non-user EQ presets are awful, but the SRC re-sampler is interesting. I've not really spent enough time to suss things properly, but dear me, bass just bubbles out of nowhere when sampled up to 192 over the source's 88kHz. I'm enjoying 24/88 Daft Punk right now. Very much.
 
Seems to have very good resolution behind the Noble Audio K10, though background noise is evident. It's not a lot of background noise, but more than I had expected. The X5/X3 have less. Ditto DX90 and AK100. But this player sounds better than the AK100 stock. It really does seem to have a good balance of low-mid detailed sound and good resolution. 

 
Background noise is combination of high output power and impedance.  It's more noticeable with sensitive headphones.  If you check my AP100 review, specifically an updated post with Penonaudio accessories I received with it (http://www.head-fi.org/t/721487/review-of-hidizs-ap100-portable-hifi-music-player/135#post_10701152) - I would highly recommend 75 ohm impedance adapter if you want to silence the noise floor.  Btw, are you planning to post your review on Head-Fi or somewhere else?  Not sure about "HFN" reference.

 

[shigzeo]

I have used 75Ω resistor adapters before. Without question, almost every earphone I've used them on changes sound signatures. I'm not excited by that. 
 
Certain players that are more powerful than the AP100 do NOT hiss as much, so it isn't just a power thing. DX100, for instance, is nearly silent with the same earphones. 
 
I will post reviews here, at Ω image, and HFN (Headfonia).

 

[twister6]

  I have used 75Ω resistor adapters before. Without question, almost every earphone I've used them on changes sound signatures. I'm not excited by that. 
 
Certain players that are more powerful than the AP100 do NOT hiss as much, so it isn't just a power thing. DX100, for instance, is nearly silent with the same earphones. 
 
I will post reviews here, at Ω image, and HFN (Headfonia).

 
With headphones I tested (IM03, IM50, W40, Tenore, and Doppio) on AP100, 75 ohm resistor didn't change the sound signature, just lowered the volume and reduced hiss on those with higher sensitivity.  Only high sensitivity phones were affected with that hiss.  Btw, I heard the same comment about DX100 before, so maybe it has something to do with output impedance of AP100?  If that would be a real noise floor from internal comment, it would have affected every pair of headphones I tested it with.  But in this case, only those with high sensitivity were affected.

 

[shigzeo]

Always highly-sensitive earphones show hiss. Every source will hiss given a sensitive enough earphone. The DX100's output impedance is one of the lowest out there and its ability to put good current into low-Ω earphones is phenomenal. Hiss has to do with more than just impedance and power. The AK100 has a very high Ω output, but has less hiss. It usually has to do with how the amplifier is constructed. Some are clean, others are not. The AP100 isn't dirty per se, but it's higher noise than most modern players. The good news is that otherwise, it sounds great.

 

[twister6]

  Always highly-sensitive earphones show hiss. Every source will hiss given a sensitive enough earphone. The DX100's output impedance is one of the lowest out there and its ability to put good current into low-Ω earphones is phenomenal. Hiss has to do with more than just impedance and power. The AK100 has a very high Ω output, but has less hiss. It usually has to do with how the amplifier is constructed. Some are clean, others are not. The AP100 isn't dirty per se, but it's higher noise than most modern players. The good news is that otherwise, it sounds great.

But how do you explain that a number of headphones are dead silent connected to AP100?  If there would be something wrong with a design, amp section, wouldn't that affect every headphone connected to it?

 

[shigzeo]

As fe as I can tell (and I've had only a few days with the AP100) there is nothing wrong with its output. Noise levels are higher than from the DX or AK series, that's all.

Plenty of great amps out there are noisy. And the AP100 is quieter than all of them. Noise at the ear is just something that happens in certain types of circuits, regardless of the DACs used. It doesn't mean bad or good.

It means that the best bet for listening heat will be headphones or speakers that are less sensitive. That's all.

 

[JFM1]

Just received the AP100 and have exactly the same problem with internal memory. Haven't tried external memory yet. Link to update software on Hidizs website appears not to work.

 

[JFM1]

UPDATE - Problem was faulty USB cable supplied with AP100. Tried another and now it works perfectly.

 

[Superdud]

AP100 with FiiO E11K
Anybody tried the AP100 with FiiO E11K ? . Was wondering how do they pair together .I'm looking at getting them with the 10% discount here:
http://a1futureshop.com.au/index.php?route=product/product&path=73_260&product_id=678

 

[twister6]

  AP100 with FiiO E11K
Anybody tried the AP100 with FiiO E11K ? . Was wondering how do they pair together .I'm looking at getting them with the 10% discount here:
http://a1futureshop.com.au/index.php?route=product/product&path=73_260&product_id=678

 
Pairs up pretty good from LO, but not HO.  Btw, in comparison as I mentioned in my E11k review, X5 pairs up better from LO with E11k than AP100 from L0 with E11k.
 
Btw, why do you need to pair up AP100 with E11k?  Unless you are driving high impedance phones, AP100 has PLENTY of power and its built in amp is very good.

 

[goodvibes]

   
Here you can see a French tube amp maker... that build and sell "A class" tube amps without ANY passive component on the signal, ONLY tubes

WHEN WE WANT WE CAN !
We have to try harder !

http://www.audiotub.fr/site1.htm

 

Not entirely true, there is a DC blocking and impedance matching output transformer that can have just as large or larger effect than a coupling cap. No free lunches. Looks to be some resistors and chokes as well. If you look at an OTL amp that will have a lot of output tubes in parallel to lower output impedance, they use very large coupling caps in place of the transformer and consider it an advantage so it's all relative and debateable. The issue becomes whether adding servo circuitry etc has a greater adverse effect on the sound than properly voicing in a coupling capacitor. You can also include the coupling capacitor in a feedback loop to minimize it's effect even further. As CieOs stated. The biggest hindrance to coupling caps in DAPs is size. Given a proper value, a coupling capacitor is probably not the weakest link in a design unless it was poorly chosen.
 
If you have a multi way speaker or IEM, there will be a coupling cap(s) before the tweeters or mid and it certainly shouldn't deter you if you like the performance. Lots of very good things use coupling caps in various positions and that likely includes the inputs of most respected portable amplifiers. In fact, the schematic above appears to show a capacitor coupled input but there may be a bypass switch for when optimum conditions exist like what would likely be a capacitor coupled tube preamp. Could also be for test purposes.
 
Just translated the description and found this: 

[color=rgb(33, 33, 33)] ONLY 1 CAPACITOR INPUT TO ISOLATE THE SOURCES [/color]

 I had a similar discussion in another thread where the fellow I was posting with changed his posts after being corrected and fained ignorance. If I'm wrong here, I'll happily admit it. 

​ I'm quite aware that I'm less than perfect.

 
 
My point here is basically that lot's of these absolutes aren't and even though I have a clue about this stuff, things like this would never have me hesitate a purchase if I just like the way something sounds.

 

[JFM1]

Further update - after getting the USB cable sorted there were still some issues. Contact with Hidizs tech support provided a link that worked to upgrade the software. However that did not solve the problem of the unit discharging itself in about 12 hours even when not being used. It needed a hard shut down to prevent that - not practical in daily use. However I was able to return the unit to mp4nation for a full refund and decided to pay the difference and go with an X5. I am happy to see the field of devices expanding and wish Hidizs well. Will be interesting to see how it compares to the Pono player. 

 

[LenMargaux]

I don't have iBasso or A&K or Fiio, but between the AP100 and HM-700, the AP100 totally wins.

 

[hk29]

What's the difference between HO and LO? Both seem to be variable, anyway to make the LO fixed?

 

[fxim]

Sorry posted in wrong tread