Fosi K7 Gaming DAC and HP Amp Review

[TehMowat]

Received my unit a couple days ago to pair with a Sennheiser HD490 Pro for gaming on PS5 and late night movies (optical to tv). Would it be worth getting a balanced cable for the HD490 Pro or will I not hear any sound upgrade? Saw balanced goes to 2.1w and unbalanced 600mw.

I have the Fosi planar headphones, they can connect either way with swappable cables, and I havnt noticed a difference between the two on my K7. I also havnt spent that much time A/B testing, and it could also be that the Fosi headphones are efficient enough that they dont care which you use.

 

[Roland68]

Received my unit a couple days ago to pair with a Sennheiser HD490 Pro for gaming on PS5 and late night movies (optical to tv). Would it be worth getting a balanced cable for the HD490 Pro or will I not hear any sound upgrade? Saw balanced goes to 2.1w and unbalanced 600mw.

If you have enough power, you don't need a balanced cable.
Any claims of sound improvements or differences between single-ended and balanced connections on the same device are a typical myth—nothing but fairy tales.

 

[TehMowat]

If you have enough power, you don't need a balanced cable.
Any claims of sound improvements or differences between single-ended and balanced connections on the same device are a typical myth—nothing but fairy tales.

Sure, but higher impedance headphones might be happier with the 4.4 mm output, but not because the 4.4 mm is balanced.

 

[Roland68]

Sure, but higher impedance headphones might be happier with the 4.4 mm output, but not because the 4.4 mm is balanced.

What is the higher impedance—or the 4.4mm connection, for that matter—supposed to have to do with it?

 

[TehMowat]

What is the higher impedance—or the 4.4mm connection, for that matter—supposed to have to do with it?

I believe, and the previous commenter also stated, that the 4.4mm output had a higher power output. Not all headphones are easily driven by all devices. Phones can't power high end, high impedance headphones. Am I saying something incorrect or controversial here?

 

[Roland68]

I believe, and the previous commenter also stated, that the 4.4mm output had a higher power output. Not all headphones are easily driven by all devices. Phones can't power high end, high impedance headphones. Am I saying something incorrect or controversial here?

Higher or lower impedance has absolutely nothing to do with the power required, nor does the quality of the headphones.
Headphones with either low or high impedance can have high or low sensitivity; the power needed to achieve a specific volume level depends on that sensitivity.

That is precisely why I explicitly stated that there is no difference provided there is sufficient power.
A balanced headphone amplifier uses two output stages per channel—compared to the single-ended output's one—in a push-pull configuration. Theoretically, this yields four times the power, a figure the K7 comes very close to achieving.
The downside is increased noise, resulting from the noise of both output stages being additive.
That is really all there is to it. If you drive a pair of headphones at the same power level using either output, there is no difference. If that isn't possible, it simply means the single-ended output lacks sufficient power.
Unused headroom does not result in any change to the sound.

 

[CedarX]

Phones can't power high end, high impedance headphones.

The phones I know can’t drive much of any headphones: no audio output. If you use a dongle with your phone, then it’s all about where the dongle gets its power from, whether it has internal DC boost circuitry and in the end, if the rail voltage is high enough, that dongle will drive any sane high-impedance HP from the 3.5mm output.

 

[TehMowat]

Higher or lower impedance has absolutely nothing to do with the power required, nor does the quality of the headphones.
Headphones with either low or high impedance can have high or low sensitivity; the power needed to achieve a specific volume level depends on that sensitivity.

That is precisely why I explicitly stated that there is no difference provided there is sufficient power.
A balanced headphone amplifier uses two output stages per channel—compared to the single-ended output's one—in a push-pull configuration. Theoretically, this yields four times the power, a figure the K7 comes very close to achieving.
The downside is increased noise, resulting from the noise of both output stages being additive.
That is really all there is to it. If you drive a pair of headphones at the same power level using either output, there is no difference. If that isn't possible, it simply means the single-ended output lacks sufficient power.
Unused headroom does not result in any change to the sound.

You are putting a lot of words in my mouth. If that is true how balanced outputs are theoretically 4x the power from unbalanced outputs, cool I learned something. All I said is some headphones require more power. That is a very true statement. I didn't say anything about more power equating to better sound quality on all headphones.

 

[Void]

This one doesn’t have the footstep enhancer like the C3 right? Is the SINAD enough?