HiFiMAN HM-901 visit pg 18. IMGS pg 19. NEW beta FW 1st page. . to the 901s. .new 901s FW .
Jun 16, 2013 at 4:25 AM Post #271 of 3,445
It is not a lesser card. It is balanced with attention to the needs of IEM's. I don't know all the details but it will be made to get the most out of balanced IEM's.


Thanks man! Was hoping to give myself an excuse to not wait for this iem amp board but guess I still need to wait for a demo after all! Any word on expected availability?
 
Jun 16, 2013 at 8:08 PM Post #273 of 3,445
Production looks to be a max of 1000 a month right now as that is the most they can receive of the stepped attenuator due to the time it requires to manufacture the control. 
 
Jun 16, 2013 at 10:46 PM Post #274 of 3,445
It's a shame that there is no USB DAC option directly on the HM-901. 
 
I think a Mini/Micro Dock for travel would be a nice option that would bring it into equal feature set with the HM-801.  Really liked the swiss army knife aspect of having so many connection options.
 
As it stands, you can't do more than two things without the large desktop dock with the proprietary connector on the HM-901.  Want to recharge and do line out at the same time on the go?  Sorry, can't do that.  Want to recharge and SPDIF input at the same time?  Sorry, can't do that either.  Want to recharge, SPDIF, and Line out to an external amp?  Nope.  Pick one.
 
Also, the HM-901 cuts off a significant portion of the first part of every track played, which is made even worse with gapless,  Hopefully it gets fixed in the next firmware update.  
And the UI while much nicer and more intuitive than the HM-801, is much slower than the HM-801.  There is a 2-5 second delay when trying to play another song when navigating to another folder.  Which is extremely irritating. 
 
That said, I really like the HM-901.  It is a definite improvement in Sound Quality over the HM-801.  But it's a big step backwards in features and UI performance.
But in the end, Sound Quality reins supreme. 
 
Jun 16, 2013 at 10:55 PM Post #275 of 3,445
Quote:
It's a shame that there is no USB DAC option directly on the HM-901. 
 
I think a Mini/Micro Dock for travel would be a nice option that would bring it into equal feature set with the HM-801.  Really liked the swiss army knife aspect of having so many connection options.
 
As it stands, you can't do more than two things without the large desktop dock with the proprietary connector on the HM-901.  Want to recharge and do line out at the same time on the go?  Sorry, can't do that.  Want to recharge and SPDIF input at the same time?  Sorry, can't do that either.  Want to recharge, SPDIF, and Line out to an external amp?  Nope.  Pick one.

 
My thoughts as well. Still interested in hearing one for sure, but it seems like the DX100 would be a better TOTL portable rig from a feature-set perspective. 
 
No personal experience on my part, just casual observation. 
 
Jun 16, 2013 at 11:17 PM Post #276 of 3,445
For in office or home use attached to a computer, the HM-901 Dock will be perfect.  If true asynchronous USB 24/192 is supported, it's all I'll need for Home and Office use.   But I'd also like Asynchronous USB 24/192 (or at the very least 24/96) for travel.  The Current Dock is huge, way too much for travel.  I would like to see a mini dock with all you need, but no frills, and small and light as possible.
 
Also, a dedicated spare battery charging box would be great as well, and would also address the overheating issue with charging while using the HM-901 at the same time. 
 
That said for travel use for music only on the go, the HM-901 is an all in one unit.  The stepped attenuator is fantastic, so cutting out, or audible clicks in between steps. 
 
Also, being able to have a single 128GB SDXC card on it is awesome.  Can't wait until there are affordable 256GB SDXC cards available.  :)
 
Jun 16, 2013 at 11:49 PM Post #277 of 3,445
It's a shame that there is no USB DAC option directly on the HM-901. 

I think a Mini/Micro Dock for travel would be a nice option that would bring it into equal feature set with the HM-801.  Really liked the swiss army knife aspect of having so many connection options.

As it stands, you can't do more than two things without the large desktop dock with the proprietary connector on the HM-901.  Want to recharge and do line out at the same time on the go?  Sorry, can't do that.  Want to recharge and SPDIF input at the same time?  Sorry, can't do that either.  Want to recharge, SPDIF, and Line out to an external amp?  Nope.  Pick one.

Also, the HM-901 cuts off a significant portion of the first part of every track played, which is made even worse with gapless,  Hopefully it gets fixed in the next firmware update.  
And the UI while much nicer and more intuitive than the HM-801, is much slower than the HM-801.  There is a 2-5 second delay when trying to play another song when navigating to another folder.  Which is extremely irritating. 

That said, I really like the HM-901.  It is a definite improvement in Sound Quality over the HM-801.  But it's a big step backwards in features and UI performance.
But in the end, Sound Quality reins supreme.


The UI lag wasn't as bad when I demo it at the shop. Though they only loaded about 30 or so tracks on it and I didn't have my SD adapter to use my micro cards. To me the 901 reacted quicker than dx100...
 
Jun 17, 2013 at 12:46 AM Post #278 of 3,445
Just a heads-up for those in China: A few units of the 901 are now available at the official Hifiman Taobao store. Grab one while you can :)
 
http://detail.tmall.com/item.htm?spm=a1z10.3.w17-604842051.37.2BTq7P&id=19662835291&_u=h241p497232
 
Jun 17, 2013 at 3:21 AM Post #279 of 3,445
There are approximately 70 employees at this site, which was manufacturing and assembling the HiFiman headphone amplifiers and daps. Testing of some headphones also is done here as well as research and development. 
 
 

 
Upon entering the main section of the factory, you see many HM901's assembled and being tested. 
 

 
One of the many tests the HM601 undergoes. 
 

 
Testing of the HM901. 
 

 
Close inspections of assembled parts. 
 

 
S/N ratio and channel separation is checked on each and every HM901 and is recorded. 
 

 
Assembly of a HM901. 
 

 
Volume control found in the HM901. The coin in the foreground is a little larger than a US dime. 
 

 
Inspection and assembly line. 
 

 
Volume control being assembled and readied for the HM901. 
 

 
Inspection and cleaning of solder points. 
 
A full set of images can bee seen HERE
 
Jun 17, 2013 at 3:56 AM Post #281 of 3,445
Quote:
Jamato8, awesome job! Love the pix. Did you get to interview Fang?

Yes, he was there the whole time and it was Fang that I asked what each station was and received any information. 
 
Jun 17, 2013 at 4:20 AM Post #282 of 3,445
Quote:
Yes, he was there the whole time and it was Fang that I asked what each station was and received any information. 

Quite impressive images. Very glad that Dr. Fang so kind to show the assembly line of Hifiman products.
 
I guess the manufacturing quality in Hifiman factory can be further improved as below:
 
1) To wear Anti-static (ESD) safe attires such as ESD safe smock & ESD safe shoes. I can see some of them wear them but not all.
 
2) To wear ESD wrist strap during the assembly process. ESD charge might degrade or even kill the ICs or others sensitive components on the PCB.
 
3) To wear hair cover & mask to prevent any foreign materials such as hair, debris, moisture from contacting with any components of the assembled unit or even WIP.
 
4) To use finger cots instead of bare fingers to contact with any components because the sweat from the fingers or hand can be easily transferred to the components.
 
5) To calibrate the torque driver to a proper torque value in order to avoid the under-torque or over-torque that might cause screw head broken. May be Hifiman has done the calibration.
 
Jun 17, 2013 at 6:14 AM Post #284 of 3,445
Quote:
It's a shame that there is no USB DAC option directly on the HM-901. 
 
I think a Mini/Micro Dock for travel would be a nice option that would bring it into equal feature set with the HM-801.  Really liked the swiss army knife aspect of having so many connection options.
 
As it stands, you can't do more than two things without the large desktop dock with the proprietary connector on the HM-901.  Want to recharge and do line out at the same time on the go?  Sorry, can't do that.  Want to recharge and SPDIF input at the same time?  Sorry, can't do that either.  Want to recharge, SPDIF, and Line out to an external amp?  Nope.  Pick one.
 
Also, the HM-901 cuts off a significant portion of the first part of every track played, which is made even worse with gapless,  Hopefully it gets fixed in the next firmware update.  
And the UI while much nicer and more intuitive than the HM-801, is much slower than the HM-801.  There is a 2-5 second delay when trying to play another song when navigating to another folder.  Which is extremely irritating. 
 
That said, I really like the HM-901.  It is a definite improvement in Sound Quality over the HM-801.  But it's a big step backwards in features and UI performance.
But in the end, Sound Quality reins supreme. 

Regarding UI response:
Have you tried removing all non-audio files from the SD card and internal memory? This could help.
 
Regarding cutoff of first part of a track:
Are there any other HM-901 owners who has experienced this?
 
Jun 17, 2013 at 6:43 AM Post #285 of 3,445
Mine seems to start at the 1st second of play, right at the beginning. I will pay more attention. Seek time, when I go to another album is pretty fast, 2 seconds or so, 1 thousand one, 1 thousand 2 and it is there, fast enough for me. 
 

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