The Centrance HiFi M8 thread
Oct 1, 2012 at 8:41 PM Post #106 of 5,999
Q: Concerning the battery, how easy is it to user-replace? I like good gadgets that last forever, and being able to replace the battery without shipping the unit back to CEntrance will be a bonus.
A: It may be possible to replace the battery, but I see a couple of issues: 1) The battery is custom-made for CEntrance, so you may not be able to find an exact replacement. 2) The battery should last a long time, so you should not actually need to replace it. 3) The unit is packed very tightly inside, so it's possible to inadvertently break something if you don't know how to open it up. In summary, I think we would request that you sent the unit to us. Having said that, I don't think this would be a real issue.
 
Q: I would be extremely interested in a true line out option on this letting me send the signal to my home amp and using the internal amp for my portable.
A: We are struggling with this one. Turning the volume pot "off" is effectively what you are asking about. We don't think that this would be possible. However, the XLR outputs will feature low noise and distortion, so they should be perfectly fine for driving the home setup. The XLR outputs, even though designed to drive headphones, are as good driving line-level signal. The only issue is you may need to position the volume pot in the middle. We will have more info on that soon.
 
Oct 2, 2012 at 4:07 AM Post #108 of 5,999
Michael @ CEntrance
 
Thank you for taking the time to respond to my questions and acknowledging my vote for Toslink.
 
Oct 2, 2012 at 8:26 AM Post #109 of 5,999
Sponsors aren't suppose to compare products. I'm just referencing the size of the CEntrance HiFi M8 with similar portable devices so people can get an idea of the actual size.
 
[size=13.333333969116211px]80(W) x 30 (H) x [/size][size=13.63636302947998px]125 (D) mm[/size]

 
 
 
Fostex HP-P1 below.
 

75(W) x 25(H) x 130(D) mm
 

http://www.head-fi.org/gallery/image/view/album/120193/id/631050/sort/display_order
 
Oct 2, 2012 at 9:01 AM Post #110 of 5,999
Quote:
 
Q: I would be extremely interested in a true line out option on this letting me send the signal to my home amp and using the internal amp for my portable.
A: We are struggling with this one. Turning the volume pot "off" is effectively what you are asking about. We don't think that this would be possible. However, the XLR outputs will feature low noise and distortion, so they should be perfectly fine for driving the home setup. The XLR outputs, even though designed to drive headphones, are as good driving line-level signal. The only issue is you may need to position the volume pot in the middle. We will have more info on that soon.

 
Forgive my ignorance but how will the 1 ohm output of the XLR headphone output influence the signal into my full size amplifier? If I remember correctly, the Dacport LX has an output impedance of 60 ohm.
 
Oct 3, 2012 at 12:53 AM Post #111 of 5,999
The rule with feeding audio from one device to another (or from one stage to another within a device) is "low impedance leaving, high impedance receiving".
 
This means that the output impedance of the preceding (sending) stage needs to be lower than the input impedance of the subsequent (receiving) stage. So, if the output has low impedance and the input has high impedance, you are fine. In general, you want to have more than 10 times the difference in impedance between the output and the input. 
 
So, when the output impedance of the XLR jacks is 1 Ohm, and the input impedance of the amp that you are feeding is 10k Ohm (a typical value in consumer electronics), you have a difference of 10k times. This is quite fine, nothing to worry about.
 
The nominal output impedance of DACport is 10 Ohm, but we can lower it to 1 Ohm with a custom "1 Ohm mod." This is why DACport can confidently drive any amp, and also long cables. Both HiFi-M8 and DACport are perfectly suited to connecting their outputs to external amps. The only issue is the volume knob that may need to be set to middle, in case the level is a little too high for the amp.
 
Oct 3, 2012 at 1:45 AM Post #112 of 5,999
Guys, we need some help. It may be time to pull together another one of them surveys...
 

We have a choice with HiFi-M8:

- About 5 hours of battery life and output performance that’s equal to DACmini (pretty much any headphones, incl. over-the-ear)

- About 8 hours of battery life and output performance that’s equal to DACport (most headphones, certainly all IEMs)

How many people really need to drive the tough-to-drive HiFi Man cans? We are going to be fine with most IEMs regardless...

Thanks for your help, in advance!

Here is the blog post explaining this in more detail:

http://centrance.com/products/new/blog/2012/10/03/output-level-dilemma/

 

 

 
Oct 3, 2012 at 1:55 AM Post #113 of 5,999
Assuming the LX can only be used via a USB input, it can probably be charged via the same USB input during use, so higher output (less battery life) will make sense with the LX?
 
As for the full fledge version, it certainly is a tough choice. If the higher output is chosen, make sure it's hiss free! 
Would something like the LCD-2 fall under the requirement for higher gain?
 
--
I think it's important that the HiFi M8 has the ability to drive most balanced headphones. This range from HD650, to HD800, to Audezes.
Then even more so the ability to be hiss-free for the most sensitive IEMs.
 
Seems like a tough call, but I believe CEntrance can do it!
 
 
Survey for output, battery level of the CEntrance HiFi M8
 
Oct 3, 2012 at 2:08 AM Post #114 of 5,999
Quote:
Guys, we need some help. It may be time to pull together another one of them surveys...
 

We have a choice with HiFi-M8:

- About 5 hours of battery life and output performance that’s equal to DACmini (pretty much any headphones, incl. over-the-ear)

- About 8 hours of battery life and output performance that’s equal to DACport (most headphones, certainly all IEMs)

How many people really need to drive the tough-to-drive HiFi Man cans? We are going to be fine with most IEMs regardless...

Thanks for your help, in advance!

Here is the blog post explaining this in more detail:

http://centrance.com/products/new/blog/2012/10/03/output-level-dilemma/

 

 

Hello again, Mr Goodman, it may be quite late in the development, but is it possible to add a jumper near the battery or something that will adjust voltage supply or power levels? That way, users may also choose the performance and battery life they want. So far, I only see this jumper in for battery devices in Fiio's E11. This also goes with the design philosophy of having as many choices as possible with the M8. That way, it will not require a redesign of casework as well.
 
Oct 3, 2012 at 3:03 AM Post #117 of 5,999
Thanks, Guys. Really appreciated. LCD-2 should be supported in any case.
 
Regarding the switch - we will have a 3-position gain switch to match to the headphones, already. The question here is maximum output power, when the switch is at the max setting and you still (possibly) need some more juice. Unfortunately, we can't include another switch. The choice of battery life is determined by the chips we use. We can only put one type of chip on the board - there is no space for both kinds (believe me, we tried). So we need to commit to the final chip. We think we know where we're headed, but I want to hear from the community first. Please fill out the survey -- eron rocks!
 
Oct 3, 2012 at 3:25 AM Post #119 of 5,999
Yeah... So far the preference is overwhelmingly power over battery life.
 
The community has spoken. We have listened. I'm locking myself in the design office to "redo everything" in the next couple of days :wink:
 
Thank you, guys!
 

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