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HM-901 - Page 74

post #1096 of 3059

When/if I receive it, I will text you and see if you have the time to audition properly!

post #1097 of 3059

Anyone who has the HM-901 with balanced amp that could tell me how it does with sensitive IEMs / CIEMs ?

I am thinking particulary about output impedance and low level listening.

post #1098 of 3059
Quote:
Originally Posted by gameguytw View Post

 

 

 

 

 

 

 

 


 

 

 

Quote:
Originally Posted by czqdtc View Post

The volume nob on hm901 is terrible... It only goes by half a whole digit, 0, 0.5, 1, 1.5 for instance, as apposed to the actual mark on it, which is kindalame...

I found my JH16 too loud on1 while being not loud enough on 0.5 o_O

 

Quote:
Originally Posted by Mython View Post

 

This is unfortunate but it makes sense, since the HM-901 volume control is not a potentiometer in the conventional sense - instead, it is a stepped attenuator.

 

However, I would personally still prefer an ALPS potentiometer (size notwithstanding).

 

I'm still keen to hear the HM-901, when (if) it is eventually released internationally, but it does seem as though it might have fallen at the final hurdle, in terms of it's industrial design execution, judging by reports of failing buttons etc.

 

The mid-level hi-fi DAP marketplace is very rapidly heating up, thanks to Fiio (X5), iBasso (D-50) etc., and this will very likely increase further in the coming year or 2, and these will be nipping at the heels of the top-end DAPs. The top-end flagship statement DAPs (DX100, HM-901 etc.  <AK120 does not count as top-end, since it's primarily an exercise in marketing greed, rather than engineering substance>) will need to be executed very successfully or people will instead buy the best of the mid-level hi-fi DAPs.

 

I hope HiFiMan manage to overcome the problems with HM-901 buttons etc. and bring it successfully to the international market. I'm a fan of the DX100, sound quality-wise, and therefore I respect the HM-901 for (apparently) competing well, SQ-wise, with it. I would like the chance to experience it.

 

 

Quote:
Originally Posted by goodvibes View Post

It's a continuous potentiometer with detents and stiff enough that you can do mid steps. I only listened for a few to it but I don't believe it just changes V at the steps.

 

 

Quote:
Originally Posted by LarsHP View Post


Are you sure that it isn't a stepped attenuator? IIRC it is supposed to be that.

Quote:
Originally Posted by goodvibes View Post

Semantics. It's a  continuous pot/attenuator with detents/steps. If it were a true analog stepped attenuator, it would take 100 resistors bridged across a similar # of contacts.

 

 

 

 

Quote:
Originally Posted by Mython View Post

 

It seems I (may) stand corrected.

 

If so, thanks for your clarification.

 

I would still like to hear about this directly from Fang, though, since he has claimed all along that he has implemented a 'stepped attenuator' on the HM-901, and it does seem odd (to put it mildly) for him to make a big deal about implementing a 'stepped attenuator' if it turns out to be nothing more than a standard potentiometer with indentations. That would tend to make him look silly in the eyes of the audiophile community.

 

 

Quote:
Originally Posted by jamato8 View Post

If you charge the 901 and play at the same time, because of the op amps and charging circuit, the 901 can get too warm so HiFIman states you should charge the 901 and then play it on the battery, not while plugged into the charger. 

 

 

I went to the factory today. Very interesting. Quite a large spread. HifFiman has too factories. The one I went to is for the daps and amps. I think there is something like 70 employees where I was. All assembly is done in house with significant testing and checking of each dap and amp with frequency tests and burn in periods to check the battery performance and the the units are rechecked. 

 

I have images and much more date I will post. 

 

There will be 6 boards for the 901. 

 

The volume control is a true resistor based unit. Hand made with 23 steps. I have an image of one opened up showing all the resistors. It most likely the smallest stepped attenuator made. 

 

 

 

Oh man, I thought this one had been put to bed as not being a true stepped attenuator. I'll be really interested to see your detailed pics, Jamato8!

 

 

 

 

Quote:
Originally Posted by AmberOzL View Post

Can you say, all these delay is actually worth waiting?

 

 

There's something about the 901. It's really cheesed me off how the release of it has been handled, and I've pretty much decided it's not worth the hassle after so long, and yet... and yet.... SIGH...!! biggrin.gif

 

.


Edited by Mython - 6/15/13 at 6:12am
post #1099 of 3059
Quote:

Originally Posted by Mython View Post

 

There's something about the 901. It's really cheesed me off how the release of it has been handled, and I've pretty much decided it's not worth the hassle after so long, and yet... and yet.... SIGH...!! biggrin.gif

 

.

 

same thoughts here.

 

maybe it has something to do with dual sabre 9018, NO pop sound, balanced design built in + swappable balance card and pretty handy.

all the pointers that the ibasso dx100 doesn't have.

 

now if ibasso were to announce something with all those added in a new dx100 ...

post #1100 of 3059
Quote:
Originally Posted by kenz View Post

 

same thoughts here.

 

maybe it has something to do with dual sabre 9018, NO pop sound, balanced design built in + swappable balance card and pretty handy.

all the pointers that the ibasso dx100 doesn't have.

 

now if ibasso were to announce something with all those added in a new dx100 ...

 

Well, I do still like the DX100 (but don't deny some aspects of the DX100 drive me nuts).

 

But, one thing I really would like in a high-end DAP is to not have to suffer the loud POP sound of the DX100, which, in my opinion, cannot possibly be completely harmless to sensitive CIEMs, no matter how many 'experts' tell me it's completely harmless. It's certainly not harmless to my eardrums, I can say that with absolute certainty!

post #1101 of 3059
Quote:
Originally Posted by Mython View Post
Oh man, I thought this one had been put to bed as not being a true stepped attenuator. I'll be really interested to see your detailed pics.

I am not sure what what you mean. Do you mean that you wonder if there are actual individual resistors, one at each of the 23 steps? 

post #1102 of 3059
Quote:
Originally Posted by Mython View Post

 

Well, I do still like the DX100 (but don't deny some aspects of the DX100 drive me nuts).

 

But, one thing I really would like in a high-end DAP is to not have to suffer the loud POP sound of the DX100, which, in my opinion, cannot possibly be completely harmless to sensitive CIEMs, no matter how many 'experts' tell me it's completely harmless. It's certainly not harmless to my eardrums, I can say that with absolute certainty!

 

Same sentiments here.

 

The plugging and unplugging after powering the dx100 up is also a concern as it wears out the plugs unless we place some adaptors between dx100 plug and cable plug.

that affects sound quality to some extent too.

 

was hoping HM-901 to remedy this situation till the built issue came up. crossing fingers now.

post #1103 of 3059

Has Hifiman resolved the unit overheating issue during battery charging?

 

Another comment from head-fiers that after continuous playing for a a long time (4 to 5 hrs non- stop), the unit is heating up.
However, in the case of iRiver AK120, the is no such heating up issue. Has Hifiman addressed this issue as well?

post #1104 of 3059
Quote:
Originally Posted by jamato8 View Post

I am not sure what what you mean. Do you mean that you wonder if there are actual individual resistors, one at each of the 23 steps? 

 

Yes.

post #1105 of 3059
Quote:
Originally Posted by Mython View Post
Yes.

Yes, it does. It most likely is the smallest made. I will post an image, maybe tomorrow. Too tired to process the images tonight. I took many images of assembly, testing, frequency testing, and misc and did some macro work of the internal of an opened attenuator. 

post #1106 of 3059
Here comes the $250 (1,499 RMB) Minibox ES amp card with OPA627 and BUF634

http://detail.tmall.com/item.htm?id=18788825922

http://www.erji.net/read.php?tid=1484393

T23DFKXbNdXXXXXXXX_!!1014267508.jpg
post #1107 of 3059


It arrives, and it plays music.
post #1108 of 3059
Quote:
Originally Posted by jamato8 View Post

Yes, it does. It most likely is the smallest made. I will post an image, maybe tomorrow. Too tired to process the images tonight. I took many images of assembly, testing, frequency testing, and misc and did some macro work of the internal of an opened attenuator. 

Thanks for that. Would love to see the pic.bigsmile_face.gif To me it's not a big deal other than low level tracking is assured.

post #1109 of 3059
Quote:
Originally Posted by cyberalpha11 View Post

However, in the case of iRiver AK120, the is no such heating up issue. Has Hifiman addressed this issue as well?

 

Ever used a 4G high end Android phone and tried charging it and constantly using 4G on it?  Gets pretty toasty, right?

 

Then try the same thing on a slower 3G phone, much cooler running.

 

So, yeah, the iRiver AK120 is yet another DAP that uses the WM 8740.   Of course it's going to run cooler.    Sure there are a lot of tricks to getting DAC's to sound great, but basing a DAC on the WM 8740 is an uphill battle in getting high end sound quality. 

post #1110 of 3059
Quote:
Originally Posted by Edwood View Post

Ever used a 4G high end Android phone and tried charging it and constantly using 4G on it?  Gets pretty toasty, right?

Then try the same thing on a slower 3G phone, much cooler running.

So, yeah, the iRiver AK120 is yet another DAP that uses the WM 8740. Of course it's going to run cooler.    Sure there are a lot of tricks to getting DAC's to sound great, but basing a DAC on the WM 8740 is an uphill battle in getting high end sound quality.

Em... Don't ever had much heat issue with my Note 2. Probably not high-end enough!

The 901 is hot enough just on standard amp board with 45mins of play time (not charging) that I don't feel comfortable with it in my pants, and I haven't really felt why the AK120 is facing an "uphill battle" based on what I'm hearing now. ow. Of course we all hear differently. Care to share your impressions?
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