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Topping DX3+, DX5 or something different for listening at very low volume levels?

sofastreamer

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Dec 30, 2021
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I am looking for a dac/headphone amp combo. i do not need any dsp or eq and prefer a flat neutral sound, so the dac/amp should not offer colorations in any way.
I will use it with my oppo pm2, Audeze LCD-i3 and akg k872 as well as with multi ba-iems (64 audio u8). Therefore I will need an output impedance close to zero at the headphone out which both have afaik.

I want to use my laptops, tablets and phones as sources either via usb cabeled connection or via bt ldac (phone).

now my questions: as I comparatively listen to very low volume levels, I wonder if the left and right channels will be synchronous even at those low volume levels?
Can volume levels be adjusted precisely in the first quarter of the volume controls? Is there any difference between the two?

If either the dx5 and the dx3+ work well at low volume, what would I miss with choosing the dx3+ over the dx5 for my needs? Or would you even suggest another device than one of these topping offerings?
 

audiofun

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Jul 4, 2021
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dx5 and dx3+ are both digital volume controlled, meaning there will be zero L and R imbalance.
The cost of that is the noise of the DAC chip will not be attenuated at all when you turn down the volume.
So if you have good hearing and sensitive headphones, the noise will always be there.

To lower the noise you have two options : 1) modding the resistor value of the control opamp in the composite headphone amplifier configuration. The opamp with the resistor forms a classical differential amplifier. change the resistor value there and you can make the noise lower. The penalty is you can no longer reach to the voltage swing you previous have, but based on your description this is exactly what you want. 2) use voltage divider between the amp and the headphone but in this case you no longer have zero output impedance. although in practice you won't be able to tell a 1~2Ohm output impedance with normal headphones.
 
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sofastreamer

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thx for your advice! 1-2 ohms output impedance with non ba phones are no problem, as you said. with multi ba iems it can be a different story.
Could my ifi ie-match solve the noise problem? it brings impedance down and you need to crank the volume up, when using it.
 

audiofun

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Jul 4, 2021
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thx for your advice! 1-2 ohms output impedance with non ba phones are no problem, as you said. with multi ba iems it can be a different story.
Could my ifi ie-match solve the noise problem? it brings impedance down and you need to crank the volume up, when using it.
that's exactly what option 2) is.
 
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