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HiFiMAN HM-901 visit pg 18. IMGS pg 19. NEW beta FW 1st page. . to the 901s. .new 901s FW . - Page 18

post #256 of 3412

Actually I would like to know, if possible, everything about all cards planned...and also when it will be really available in China.

post #257 of 3412

I'm guessing I already know the answer to this, but I'd like to know if there's any hope that this can be used as a standalone USB DAC in the future without requiring the dock... It may seem silly, but that's a bit of a sticking point for me, especially at this pricepoint. 

 

A fella can dream, can't he? ;)

post #258 of 3412
Quote:
Originally Posted by kkcc View Post

 

Thanks for the invite! Let's meet up when our schedules allow. If I remember correctly you have the balanced amp card right? Are you running the RE600 balanced or SE?


Balanced...

post #259 of 3412
Quote:
Originally Posted by AnakChan View Post


Thanks!

Really!? No heat issue!? Wanna swap HM-901's (but I keep my balanced module) ;-)??

AnakChan: Jin777 at Erji.net has offered some explanations. I copied his comments here. I am not a technical person so I cannot say I understand 100%. I wanted to translate but my high school physics-electrical knowledge has long lost. If you can read Chinese maybe you can make sense out of these and see if this can answer the heating - not heating question?

 

"分析901充电过程,供参考,不对请更正。

901充电分两个过程(恒流,恒压)和两个状态(关机,开机):

1.1,关机充,电池本身电量已经很低时,这时充电器在恒流给电池充电,充电器会很烫,注意不要覆

盖东西在上边,大概3-4小时后,开始恒压充电,这时充电器开逐渐变凉,共8-9小时后彻底凉下来,

充电器绿灯可能已经在后4个小时内的某个阶段熄掉了(我的一直亮着,只是变暗了)。

1.2,还是关机充,但电池有半满的电,充电器可能会很快热起来,又可能很快进入恒压状态,4-5个

小时左右就充好了,充电器慢慢就凉了。

2.1,开机充电,电池若空电,充电器又给电池充电,有给机子供电,充电器会非常烫,非常烫,

当3-4个小时或更长时间后,电池的前半段恒流充电状态基本接近结束,

但901还在开机中,电池不会转到下个状态,这时充电器只给901供电,还是有些热,

但不会像前面那么烫了,此时电池没有充满电就基本结束充电了,所以开机充不满电。

2.2,开机,电池原来还有电,类似2.1的后半部分,充电器微烫,1-2小时后若拔掉充电器电池可能显

示满格电,但没有充饱不经用,需要关机后3-4小时方能充满电。


开机充不满电:

锂电电池充电恒流过程结束后,需要恒压充电,但电流逐渐变小,这个电流逐渐变小和901开机所需恒定的电压电流是矛盾的,

所以开机时电池充电在没有达到恒流转恒压的时候就停止了,充电器通过芯片控制在检测到901开机后输出电压会下降(没有达

到电池充电所需最高电压)并保证播放所需稳定输出。

还有一种情况,当你把关机充满电的电池放到901里,插上充电器开机,这时电池也会放电,并很快就维持到开机充电时的电池

半满电状态。


总之,整个充电过程只有充电器发热,电池并不热,在901里面关机充电池也不热,开机充的热量不是

电池发出的。

我理解的大概就这样吧,随时想起写的,没有仔细斟酌,不对的请大家更正。


[ 此贴被jin777在2013-05-24 10:46重新编辑 ]"
post #260 of 3412
Thread Starter 

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 two assembly areas. The one I went to is for the daps and amps. I think there is something like 70 employees where I was. All assembly for the daps is done here 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. 


Edited by jamato8 - 11/4/14 at 9:46pm
post #261 of 3412

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

post #262 of 3412

Am sure we all want the HM-901 to succeed.

 

Just wish the built challenges were not so glaring and real potential deal breakers.

Timing is also a concern.

 

Regardless, will still want to give the 901 a try.

post #263 of 3412
Thread Starter 

There was some question about the wheel used. There was a couple of problems early on and then some changes were made and it resolved the issues. The actual internal contact that the wheel goes to has been used for a number of different types of equipment and apparently it has proven it self to be reliable and to have a very long life. 

post #264 of 3412
Quote:
Originally Posted by jamato8 View Post

There was some question about the wheel used. There was a couple of problems early on and then some changes were made and it resolved the issues. The actual internal contact that the wheel goes to has been used for a number of different types of equipment and apparently it has proven it self to be reliable and to have a very long life. 

 

That's good to know, jamato8.

 

What Fang needs to do now is give more confidence in the product for us to make the leap.

Confidence can be earned with well built quality and stable software. much like how ibasso has done.

post #265 of 3412
Thread Starter 
Quote:
Originally Posted by Theogenes View Post

I'm guessing I already know the answer to this, but I'd like to know if there's any hope that this can be used as a standalone USB DAC in the future without requiring the dock... It may seem silly, but that's a bit of a sticking point for me, especially at this pricepoint. 

 

A fella can dream, can't he? ;)

It requires a dock due to the type of USB required to do 24/192 and size constrains within the 901. 

post #266 of 3412
Thread Starter 
Quote:
Originally Posted by kkcc View Post

 

Thanks Jamato

Would like to know any and everything about the planned IEM card - availability, price, tuning charateristics, IEMs they had in mind that they tuned this for, etc.

There will be one with less power than the standard balance card but it will be made for IEM's to get the most out of them. Tuning, I am not sure of but I imagine the new RE600's from HiFiman, which so far have received very good reviews. 

post #267 of 3412

Thanks for the reply, jamato ;)

post #268 of 3412
Quote:
Originally Posted by jamato8 View Post

There will be one with less power than the standard balance card but it will be made for IEM's to get the most out of them. Tuning, I am not sure of but I imagine the new RE600's from HiFiman, which so far have received very good reviews.

Many thanks jamato and looking forward to your full report. If the IEM card is "lesser" than the balanced card I think unless it is significantly cheaper the balanced card seems like a better option even if I'm running it with SE.
post #269 of 3412
Quote:
Originally Posted by ironore View Post

AnakChan: Jin777 at Erji.net has offered some explanations. I copied his comments here. I am not a technical person so I cannot say I understand 100%. I wanted to translate but my high school physics-electrical knowledge has long lost. If you can read Chinese maybe you can make sense out of these and see if this can answer the heating - not heating question?

 

Thank you for the copy/paste. Sadly I can't even write my Chinese name :p.

 

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. 

 

 

Thanks Jamato8 for the translation. That's interesting though 'cos if you plug the HM-901 to the base station using as a USB DAC, does it "know" not to "use" the OpAmps during that mode? I'm assuming the base station would charge and operate the device simultaneously.

 

Truly looking forward to your report, thank you in advance!!

post #270 of 3412
Thread Starter 
Quote:
Originally Posted by kkcc View Post



Many thanks jamato and looking forward to your full report. If the IEM card is "lesser" than the balanced card I think unless it is significantly cheaper the balanced card seems like a better option even if I'm running it with SE.

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. 

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