[kunalraiker]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif I get around 9 to 10 hours with the 500mA Li-Polymer by iPowerUS. I have two and just keep one charged so it works out well. I have others but tend to use these lately.

Which ones are the best, I've heard theese ones are good

MAHA / POWEREX 9.6V 230mAh Rechargeable NiMH Battery

I'am using Duracell alkaline right now.

 

[mrarroyo]

Good to see so much D4 love!

 

[HiFlight]

Quote:

Originally Posted by kunalraiker /img/forum/go_quote.gif Which ones are the best, I've heard theese ones are good MAHA / POWEREX 9.6V 230mAh Rechargeable NiMH Battery I'am using Duracell alkaline right now.

These are what I am using. I have been very pleased with them. I just always keep a couple charged and ready to swap.

 

[trentino]

How long will the D4 last with a "regular" 9v alkaline? Is it much less than the 9 hrs with rechargeable 200-300 mah?

 

[kunalraiker]

Quote:

Originally Posted by trentino /img/forum/go_quote.gif How long will the D4 last with a "regular" 9v alkaline? Is it much less than the 9 hrs with rechargeable 200-300 mah?

I want to know that too.

 

[jamato8]

I get 8 to 9 hours on alkalines but it also depends upon what you are driving, i.e. the current demand/power requirement of the monitors.

 

[kunalraiker]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif I get 8 to 9 hours on alkalines but it also depends upon what you are driving, i.e. the current demand/power requirement of the monitors.

Would you consider alkaline to be good for SQ or is there something better.

 

[jamato8]

I don't hear any real difference. Maybe some others might. I also have the low dissipation 9 volt batteries, that have a lower internal resistance and they also sound good but only hold 200mA's of current so I use either alkaline, but don't like the waste, or the Li-Poly 500mA.

 

[madwolf]

Instead of changing battery ever 8 or 9 hours.
This is what I am working on.

A power circuit to be be powered from the 5V of the USB.
1) The circuit include a voltage doubler to convert the 5V supply to 9V or Higher.

2) Power regulator to fixed the output voltage

3) Filtering circuit and smoothing circuit, Currently I am experimenting with different configuration of Pie Filter. Will build the official module after I finalize the design and component used.

The module must be smaller than a 9V battery, So that it could fit inside the D4. It noise must not be audible using even the most sensitive IEM. (I am happy that my alpha attempt have already achieve this. ) The existing USB/9V switch will not be modified so that, the user could choose between the 2 power source.

The item yet to be decided is if I want to Push the D4 to 12Volts or 10.8V
To do this I might need to change the existing reservoir cap on the D4 (10V 2200uF, ibasso is already pushing on the limit by putting a 10V cap for a 9V battery) . But the advantage of this is that I could have the voltage margin to play with the holy 3 of OP-AMP, namely OPA627, LT1028 and AD797 for the LR. Buffer would likely be the BUF634 *4 in wide-band mode. A higher voltage would have a greater headroom as well, But there is a limit to how much power I could draw from the USB.

I will continue to tinker with the design and hopefully improve it further.

The Sick part of all this, The D4 and power circuit is not mine, Just modding for fun for a friend FOC. I feel I starting to enjoy modding circuit more than listening to music already.

 

[mrarroyo]

madwolf, that is sick! I love it.

Look forward to seeing pictures of the finished product.

 

[chesterqw]

i got a reply from ibasso telling me that the D4 can handle up to 10V
li-ion 9Vs!!! woot!
more burst power ftw!

 

[jamato8]

I have been using li-Poly and true 9.6 volt batteries in it with no problem. On the Li-Poly for some reason I have started getting around 12 hours of run time, longer than before. They are 500mA.

 

[foreverfi]

Quote:

Originally Posted by jamato8 /img/forum/go_quote.gif They are totally different animals. The D4 Mamba is a USB dac/amp, not a player.

I think add in any cheap player as the sound sources, the sound quality will be perfect than the expensive one.

 

[A_Dying_Wren]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif I posted about that somewhere. The HD600 need more voltage swing and power than many other full size headphones. The D4's power in 5v mode is no better than the D2 or D10 in 5v mode; being slightly more than the Icon Mobile, about the same as the Predator, and very slightly less powerful sounding than the P-51. That's enough power to sound nice at normal listening volumes, but not enough to rock out with rock or electronic or to pretend like you are there at a jazz club with the musicians. However, in 9v mode the D4 is noticeably more powerful with HD600 than those above. It comes closer to the power or the Pico, which seems to be slightly below the power of the 3MOVE with 9v battery when used with the HD600. The 3MOVE in 5v mode (USB only, no battery) also suffers when driving the HD600, but with a 9v battery it does much better. So, the D4 in 9v mode, like the 3MOVE or Pico, is better for HD600 even though the others can sound nice but just not play as loud. I don't have HD650 to try, but the HD650 always seemed to me to thrive on more power than the HD600 and sounded darker to me, and the two times I've owned them I sold them. (note, I think the Vivid V1 must use a voltage multiplier or something, as it is the only 5v charging DAC/amp I've tried that seems to be able to reach the same power levels with HD600 as the Pico in previous reviews).

How many volts would a good desktop headphone amp be rated at or is the comparison meaningless? Can't quite get a grasp of where 5v or 9v lies on the grand scheme of things.

Can't wait for your review.

Thanks a lot.

Just in general, can you plug a proper amp into the D4 at a later stage and use the D4 just as a DAC? Sorry if this is rather obvious.

 

[jamato8]

The D4 can be a USB connected dac and you are utilizing the dual dacs. This can go to any amp.