HM-901

[kenz]

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1. I don't really know as I don't have any Class 10 card to test on. However you should take note that 'classes' on SD card refer to writing speed, not reading speed which is what actually affect the loading speed. I am using a Class 6 card and it doesn't feel particularly slow in reading. Also note that even a Class 4 card should be more than fast enough for full wave (uncompressed) file playback. I do remember reading from erji.net that others has successfully used Class 10 SDXC card on HM901, but it depends on brand as well.
 
2. It takes slightly longer on first start up to load ( / scan) the library and you can see album being added on-the-fly. You can play those already scanned files without waiting for the scan to be completed. It will rescan the library on subsequent restart as well, but seems to only looking for change. So if you didn't update the SD card, the rescan will only take a few seconds (or tens of second, hard to say as I didn't time it) and you can still select / listen to music while it is scanning on the background.
 
3.A 64GB will have to be a SDXC card and I don't own any SDXC card for now. Again, reading speed isn't an issue on HM901 as I didn't detect any delay between selecting files and listening to them.

 
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I just did a drain test playing 24-192 file with JH16 on a HM-901 with balanced card. It lasted for 7 hours, from full charge and self power-off.
 
I am using a Kingston 128G UHS-1 Class 10 SDXC, formatted in FAT32, but as ClieOS already pointed out, that speed relates more to writing...

 
Thanks for sharing, ClieOS & ironore.
 
Looks like the HM-901 has about the same if not slightly more battery than the DX100, which is still acceptable (at least to me).
And will remember on the card classes portion, always mix it up for read/write speeds.
 
Hope to see some reviews here soon. It's finally march and looking forward to the international launch soon.

 

[ClieOS]

Here is the report of some initial battery tests. HM901 (w/ stock amp card) was charged overnight, then it ran continuously for 4 hours / rest for 12 hours / restart till battery fully drained. The load is the slightly harder to drive 120ohm Sunrise SW-Dragon 2 on volume 3/8 (my normal listening volume). Music is mostly 16/44 mp3 file between 192kbps and 320kbps, plus some wav file. It lasted somewhere between 6~7 hours in total. Then I recharged it for 4~5 hours, rerun the test with RE400 on 1.4/8 volume (low listening volume). This time it only lasted around 5 hours or so. The second run is shorter most likely because I didn't quite fully charged the battery up.
 
HM901 can only be charged to full when turned off and the battery indicator isn't really precise enough. It only shows battery indicator of full / half / low / recharging, so there is no way to know precisely how much battery is left / charged. AFAIK, 80%, 90% or 99% could all be a full battery sign. Anyway, I think it would be safer to leave it charged overnight to order to get it full. Hopefully HfiMan will update the battery indicator on the future firmware.

 

[AnakChan]

Thank you. That is quite a thorough test. Interesting that it can get a full charge only when switched off, & 4-5 hrs of recharging is not enough to reach a full charge.

 

[ClieOS]

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Thank you. That is quite a thorough test. Interesting that it can get a full charge only when switched off, & 4-5 hrs of recharging is not enough to reach a full charge.

 
To make the DAP smaller, they remove the charging circuit from the DAP and put it inside the power adapter, so the SoC has no control over charging and can't prioritize which to come first. Also, the DAP itself draws a lot of power and therefore can never get quite full if you are using and charging it at the same time.
 
One way I have found out how to know when the charging is finished is by touching the adapter. It gets a little warm when charging and return to room temp. when it is done. Not exactly precise either but it is better than nothing at all.

 

[lee730]

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To make the DAP smaller, they remove the charging circuit from the DAP and put it inside the power adapter, so the SoC has no control over charging and can't prioritize which to come first. Also, the DAP itself draws a lot of power and therefore can never get quite full if you are using and charging it at the same time.
 
One way I have found out how to know when the charging is finished is by touching the adapter. It gets a little warm when charging and return to room temp. when it is done. Not exactly precise either but it is better than nothing at all.

So it takes about 5 hours to fully charge? The DX100 takes about 2 hours to fully charge....

 

[ClieOS]

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So it takes about 5 hours to fully charge? The DX100 takes about 2 hours to fully charge....

 
I didn't say that.

 

[kenz]

Thanks for the extra details, ClieOS.

 
Hope they improve the charging with the international version and the dap software.
Seems like the usage hours is directly proportionate to the charging cycle? Say 5 hours charge, about 5 hours usage?
Not sure if running only uncompressed lossless files will help improve battery life further.
 
Am more of an over-night charging user, so the night charging is fine by me. 

 

[lee730]

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I didn't say that.

Then how long would you think it would take to fully charge from a complete drain to 100% full?

 

[ClieOS]

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Seems like the usage hours is directly proportionate to the charging cycle? Say 5 hours charge, about 5 hours usage?

 
It is kind of misleading to say that. As I have said, there isn't any way to tell how much battery has been charged during that 5 hours between the two tests. I was just being impatient so I did the 2nd test anyway without waiting for another overnight charging. It isn't just about how fast the battery can be recharged, but also how fast the adapter is designed to charge the battery.
 
Remember than HM901 uses two Li-ion batteries with a combined capacity of 2200mAH. They are charged by a dual supply +8.4V / -8.4V charger with a 1A output (Li-ion generally top up at around 8.4V, so it can be used to explain why HM901 recharges much slower as the charging voltage is getting closer to the battery voltage, and the charging will slow down significantly due to the smaller difference between them). DX100 on the other hand has a single 2000mAH battery and being charged by a 12V, 1.5A charger - so it is not hard to imagine why DX100 can be recharged faster. DX100 has higher CPU speed (1.2GHz), bigger screen, a much more complexed firmware (Android). HM901 on the other hand has a slower CPU (600MHz), small screen and a dedicated audio only firmware, but almost double the DAC section. Overall, I don't think anyone can expect either to run very efficiently as far as battery life is concerned.
 
Anyway, I'll do more test when I have the time.

 

[ClieOS]

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Then how long would you think it would take to fully charge from a complete drain to 100% full?

 
Don't know. The only way to be sure is to take the battery out (during recharging) in regular interval and measure its voltage till it reaches it max. It will take half a day of work at least and I really don't have the time to do that now.

 

[kenz]

Thanks again, ClieOS.

 
For me, a slow charging battery is a benefit. The battery life can last longer versus a fast charge type.
Since the battery is replaceable on the go, getting a spare battery will at least ensure about over 12 hours of full charge usage.
This is a plus versus the iBasso DX100 which is a built-in battery and a fixed 7 to 8 hours (max) usage.
 
These are just rough estimates and they're already looking decent.
 
Looking forward to more insights to come.

 

[Jerseyboy]

It's good to see that the HM-901 supports a good range of file types. I'm a bit concerned though that from the published specs that although 24 bit WAV & FLAC files are supported that only 16 bit AIFF files are supported (44.1 & 48) which is a bummer really since all my files are 24/96 AIFF and the last thing I want is to have to convert my files prior to loading !!
 
Anyone know whether DX100 or C4 will support 24/96 AIFF ??

 

[ClieOS]

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It's good to see that the HM-901 supports a good range of file types. I'm a bit concerned though that from the published specs that although 24 bit WAV & FLAC files are supported that only 16 bit AIFF files are supported (44.1 & 48) which is a bummer really since all my files are 24/96 AIFF and the last thing I want is to have to convert my files prior to loading !!
 
Anyone know whether DX100 or C4 will support 24/96 AIFF ??

 
If you can point me to a place that I can get some different bitrate / bitdepth of AIFF, I can try them out for you and see how they go.

 

[ironore]

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Thanks again, ClieOS.

 
For me, a slow charging battery is a benefit. The battery life can last longer versus a fast charge type.
Since the battery is replaceable on the go, getting a spare battery will at least ensure about over 12 hours of full charge usage.
This is a plus versus the iBasso DX100 which is a built-in battery and a fixed 7 to 8 hours (max) usage.
 
These are just rough estimates and they're already looking decent.
 
Looking forward to more insights to come.

Fang said there will be an optional desktop charger. So getting a second battery makes sense and gives good mileage, when that is available.... Just hope that will not be in the year of the Horse.

 

[kenz]

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Fang said there will be an optional desktop charger. So getting a second battery makes sense and gives good mileage, when that is available.... Just hope that will not be in the year of the Horse.

 
Yeah. The thought of the complete package (HM-901 + changeable battery + changeable amp + desktop dock) is quite exciting.

 
Am seeing the HM-901 as not only a potentially top notch portable dap, it'll double up really well as a home desktop set-up also.
Price wise may seem daunting but considering its outdoor and indoor potential, seems rather reasonable.
 
And yes, do hope it lands internationally before the year is out, preferably before end June (March for HM-901, +3 months Dock).