HM-901 - Page 21

Quote:

Originally Posted by Saraguie 

Clie, any idea?

Nothing concrete - however I do have a theory. A recent re-examine of the HM801 amp module lead me to believe that the output impedance is mostly due to the output resistors on the amp module, and a simple bypass can easily drop it to under 1 ohm. Judging from the picture of the HM901's STD amp module, I don't see any output resistors on one side but it is hard to say whether they will be on the other side. Hopefully not, but in any case, the only way to say for sure is to measure it.

 Quote:

Originally Posted by Saraguie 

Clie, any idea?

Quote:

Originally Posted by ClieOS 

 

Nothing concrete - however I do have a theory. A recent re-examine of the HM801 amp module lead me to believe that the output impedance is mostly due to the output resistors on the amp module, and a simple bypass can easily drop it to under 1 ohm. Judging from the picture of the HM901's STD amp module, I don't see any output resistors on one side but it is hard to say whether they will be on the other side. Hopefully not, but in any case, the only way to say for sure is to measure it.

Thanks for your thoughts! 

High impedance wasn't exactly the main critic(and the target of the RW mod) for the iriver AK100?

One thing that sometimes I don't understand:

Almost surely portable DAPs are going to be used with IEMs, which are low impedance and in the case of BAs, can have very complicated interaction with the amp output impedance.

Knowing this, why a good company like iriver design a DAP that would screw with some most probable kind of headphone that is going to be used with their player? (I read that some ipods have up to 7 ohms of output impedance, what is btw insane if true, but that's another discussion)

I understand that it's nice to be able to plug a not so eficient can and play it loud and nice enough not so efficient cans, but, not only here in head-fi, but for the general public, most people aren't going to use 99% of the time low impedance easy to drive headphones, since almost all hard to drive headphones are focused for the pro and audiophile market? (which risk beeing troubled by the output impedance of the dap)

Yep you got it right. But iRiver made a mistake and they will not own up to it. You just have to deal with it or find a better solution (which they are out there). But each unit has its own flaws. None are perfect. The RWA AK100 happens to be one of the units with fewer issues when you take into account its portability, ease of use, battery life, and sound quality. Still it is not enough for me to keep it so my unit will be going up for sale on Friday if my first buyer backs out on the purchase.

Cheers :)
 

Quote:

Originally Posted by lee730 

Yep you got it right. But iRiver made a mistake and they will not own up to it. You just have to deal with it or find a better solution (which they are out there). But each unit has its own flaws. None are perfect. The RWA AK100 happens to be one of the units with fewer issues when you take into account its portability, ease of use, battery life, and sound quality. Still it is not enough for me to keep it so my unit will be going up for sale on Friday if my first buyer backs out on the purchase.

 

Cheers :)
 

WOW......after all the time and energy you invested. Sorry my friend it did not work out for you. I wish there would be some reviews on 901 production models. This might be the solution. Lee, have you played around with the UI online?

Quote:

Originally Posted by Saraguie 

WOW......after all the time and energy you invested. Sorry my friend it did not work out for you. I wish there would be some reviews on 901 production models. This might be the solution. Lee, have you played around with the UI online?

Nah I've already talked to a couple headfiers whose impressions on the 901 is less than savory including the build quality (feels of cheap plastic and easy to break). So I'll pass on the 901. I'd rather get a DX100 again if that was the case. Which I wont be surprisingly. I feel the Studio V 3rd ANV pairs better with my 1Plus2s than even the DX100. So I'm set :). I also heard the Studio V pairs well with the Heir 8As so we'll see :).

Quote:

Originally Posted by reddragon 


So what's now Lee? Back to the dx100? And how do you think the ak100 stands next to the dx100 in terms of sound quality?

Personally the AK100 is a better unit if you take into consideration its size and battery life (in concerns to portability). But I feel the DX100 is the better unit sound quality wise. I have to amp the AK100 to bring it up to snuff with the DX100. Still I prefer the DX100s sound overall but not by a huge margin. Regardless the Studio V 3rd ANV suites my needs even more than both units so I'm good.

When, when, when? "Where are thou HM-901?"

Quote:

Originally Posted by Saraguie 

When, when, when? "Where are thou HM-901?"

The earliest batch has been shipped to a few reviewers (they are slowly popping out on different sites / forums), but the main batch is said to be the next few days. They are however reserved for those in China who have pre-ordered it. You will probably see international release by March or later, as February is Chinese New Year and all businesses will probably shut down for half a month or so.

I had a chance to listen to one yesterday, albeit for a short time.  It has come a long way since the prototype i saw and heard a while ago, with wires dangling out of it....   I was able to put in an sd card with my tunes on it, and listen thru my iems.  I was able to plow through a few minutes of each of about 6 tracks.  I thought it sounded good enough to hand over my 801, as a down payment for the 901.  I am told that US customers should see theirs some time in March, after the first batch passes muster with the mainland Chinese customers.  Fang would rather be slow than wrong - he wants these to be as close to perfect as possible before he exports them from China.  I would say that it is a nice upgrade from the 801 in terms of form factor, features, UI, and most importantly, sonics.  It is not syrupy and forgiving, but is not bright or clinical either.  

In fact, Fang almost left with the sample sitting on my desk.  I had that brief crisis of faith where i wondered whether it would be OK to pretend that I didn't notice it was still sitting there.  Luckily my strong moral sense, and that alone (the fact that i did not have the cable needed to recharge it having absolutely nothing to do with it), caused me to hand it over before they left the building.

There were also some interesting iems, one of which Fang did leave with me to sample.

The 901 will be a serious contender, and worth the asking price for those looking for top-tier sonic performance.

Just a follow-up: those who has pre-ordered in China have began to receive their HM901. Picture here.

Someone has received their HM-901 in China !!!

Looks like he's the first one to lay his hands on this gorgeous new player from Hifiman.

http://www.erji.net/read.php?tid=1397432&fpage=0&toread=&page=1

Honestly, I think it looks amazing.

A few more semi-random thoughts about my short time with the 901.  I thought it looked very nice - as should a finished product in its price range.  The battery is huge, (in portable terms, so it should give it good run time and amp power.  The UI was pretty intuitive, I like having the single-ended/balanced connection in the same 3.5 mm jack, and switch-select-able. The leather trim is a nice touch, but for an audiophile like me, not necessary.  It is bigger than an iPod, but for me the definitive consideration is that it easily fit into my shirt pocket.  How much more portable does it need to be than that?

There are (or will be) interchangeable amp cards, which fit into a compartment under the battery.  They just drop right in - easier to change than a SIM card.

Damn, now I'm even more torqued up to get mine.