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Review and Measurements of Fiio K5 Headphone Amp

Guermantes

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nintendoeats

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I've been using a K5 as my desk-amp for a couple years now, and have been very pleased. Nowadays I pair it with an X3ii at work, so that's several hours of use per day right there. I am pleased to see that it measures well (particularly because it justifies my continuing belief that the test data that Fiio themselves post is reasonably accurate).
 
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josepfe

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I've been using a K5 as my desk-amp for a couple years now, and have been very pleased. Nowadays I pair it with an X3ii at work, so that's several hours of use right there. I am pleased to see that it measures well (particularly because it justifies my continuing belief that the test data that Fiio themselves post is reasonably accurate).
Hi Nintendoeats, I own the Hifiman 4xx and will have soon the Sennheiser 6xx. I assume that this amplifier has power enough to drive them both. I'm also interested in this amplifier because I own the Fiio X1II and I think that I can use it in the dock. However my doubt is whether it is good for the battery life of the player to have it continuously docked. Is it powered while in the dock or is it using its own battery?. I would like to know it as I still use the player from time to time in a portable manner, and I would not want to shorten its life battery. Thanks ahead for your reply!.
 

nintendoeats

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Hi Nintendoeats, I own the Hifiman 4xx and will have soon the Sennheiser 6xx. I assume that this amplifier has power enough to drive them both. I'm also interested in this amplifier because I own the Fiio X1II and I think that I can use it in the dock. However my doubt is whether it is good for the battery life of the player to have it continuously docked. Is it powered while in the dock or is it using its own battery?. I would like to know it as I still use the player from time to time in a portable manner, and I would not want to shorten its life battery. Thanks ahead for your reply!.
I can speak generally about Lithium Ion charging circuits. Once a battery is fully charged, the circuit should always allow it to discharge a bit and then stop charging it. Since my X3ii hasn't exploded yet, I infer that they have built their charging circuit correctly. So short answer, you don't generally need to be concerned about this.
 

josepfe

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I can speak generally about Lithium Ion charging circuits. Once a battery is fully charged, the circuit should always allow it to discharge a bit and then stop charging it. Since my X3ii hasn't exploded yet, I infer that they have built their charging circuit correctly. So short answer, you don't generally need to be concerned about this.
Many thanks for your prompt and concise reply!.
 

daftcombo

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K5 Pro is up on amazon in the US for $149.99:

https://smile.amazon.com/gp/product/B07WT7TYWY

Seems like a hell of a lot of product for the price, I grabbed one to check it out.

Yes, but as Amir wrote...
I can't find anything wrong with Fiio K5. The issue it has though is the impossible battleground created by the JDS Labs Atom with its combination of high power and extraordinary low distortion. Compared to that reference, the Fiio K5 falls behind one step or so.
 

JohnYang1997

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Yep and it looks to be nicely improved.
Amir will have to test it and see if the performance is improved too :D
The volume control seems to limit the performance. Otherwise a very good design.
 

DivineCurrent

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I received the Fiio K5 Pro today. So far, I am very pleased. I can't hear any noise with sensitive IEMs, and the volume control has perfect channel balance. Very convenient that it has SPDIF/Toslink input options as well, since I have noise issues with USB on my computer.
I can't tell the difference between the K5 Pro and Tone Board + Atom, so that must be a very good thing!
Not sure how much better the amp section is than the original K5, but I'd be willing to send it to Amir for measurements.
 

Veri

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I received the Fiio K5 Pro today. So far, I am very pleased. I can't hear any noise with sensitive IEMs, and the volume control has perfect channel balance. Very convenient that it has SPDIF/Toslink input options as well, since I have noise issues with USB on my computer.
I can't tell the difference between the K5 Pro and Tone Board + Atom, so that must be a very good thing!
Not sure how much better the amp section is than the original K5, but I'd be willing to send it to Amir for measurements.
@amirm anyone offered you one yet?
 

jacob

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I received the Fiio K5 Pro today. So far, I am very pleased. I can't hear any noise with sensitive IEMs, and the volume control has perfect channel balance. Very convenient that it has SPDIF/Toslink input options as well, since I have noise issues with USB on my computer.
I can't tell the difference between the K5 Pro and Tone Board + Atom, so that must be a very good thing!
Not sure how much better the amp section is than the original K5, but I'd be willing to send it to Amir for measurements.

Can you try it with 300 Ohm headphones, such as the Sennheiser HD 6XX? I'm currently in-between the K5 Pro and Tone Board + Atom. The K5 Pro is a lot cleaner, but if there is a noticeable difference I'll go for the Tone Board + Atom.

Alas, while you have ample power at 12 to 1:00 o'clock, going beyond that I could hear the bass distortion in the amplifier prior to driver doing the same.

Note that outside of testing, I would not need to go to the region where distortion was quite evident. So in practical use, there is plenty of distortion-free power available.

Is this enough to recommend the K5 Pro at the same level as Tone Board + Atom? What would you pick Amir?
 
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DivineCurrent

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Can you try it with 300 Ohm headphones, such as the Sennheiser HD 6XX? I'm currently in-between the K5 Pro and Tone Board + Atom. The K5 Pro is a lot cleaner, but if there is a noticeable difference I'll go for the Tone Board + Atom.
Both the HD600 and 6XX get plenty loud enough with the K5 Pro, and sound just as clean as Tone Board + Atom. Judging off measurements of the original K5, the Atom probably performs better in high gain than the K5 Pro. However, I only ever need to use low and medium gain on the K5 Pro for the 600 and 6XX, even with quiet classical music.

There are benefits to the K5 Pro over the Atom, such as channel balance. Using low impedance headphones like the Koss KSC75 and PortaPro really shows the channel imbalance of the Atom, and the K5 Pro doesn't have this problem. Another plus is the Toslink (Optical) connection. For some reason I have USB noise problems with my computer I can't seem to fix, and the optical connection eliminates this.

I do hear something going on in the volume adjustment at low levels however. It seems that the volume goes up in larger increments at those lower volume adjustments, but I'm talking about really low, like right above the off switch. After those 2 or 3 audible increments, it sounds fine.

I can't hear any noticeable sound quality difference between the TB+Atom and the K5 Pro. If the K5 Pro measures worse than the Atom and Tone Board, I can't hear it.
 

jacob

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Both the HD600 and 6XX get plenty loud enough with the K5 Pro, and sound just as clean as Tone Board + Atom. Judging off measurements of the original K5, the Atom probably performs better in high gain than the K5 Pro. However, I only ever need to use low and medium gain on the K5 Pro for the 600 and 6XX, even with quiet classical music.

There are benefits to the K5 Pro over the Atom, such as channel balance. Using low impedance headphones like the Koss KSC75 and PortaPro really shows the channel imbalance of the Atom, and the K5 Pro doesn't have this problem. Another plus is the Toslink (Optical) connection. For some reason I have USB noise problems with my computer I can't seem to fix, and the optical connection eliminates this.

I do hear something going on in the volume adjustment at low levels however. It seems that the volume goes up in larger increments at those lower volume adjustments, but I'm talking about really low, like right above the off switch. After those 2 or 3 audible increments, it sounds fine.

I can't hear any noticeable sound quality difference between the TB+Atom and the K5 Pro. If the K5 Pro measures worse than the Atom and Tone Board, I can't hear it.

Thanks, I ordered a K5 Pro. :)
 

ClosDeLaRoche

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Just posting to say that I picked up one of these original K5 amps on OfferUp for only $40.

I have an old X5 2nd Generation that I am docking with the K5.

It sounds damn good. It's small enough to leave on my couch's side table or my bed's nightstand. The X5 DAC integration works with both my laptop and Android phone. I am using medium gain with my Aeon Flow Open headphones and the sound is powerful, clean, with very good bass slam. I used to own an Atom and like the K5 more for a few reasons: the middle gain setting, better build quality, better volume dial and better channel matching (maybe this is not the case on all Atoms but mine had really bad channel matching on low volumes)

This one is a winner. If you have a Fiio product that can dock with it absolutely buy one of these, espceially at the price they are going for in 2019!
 

rar133

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Just posting to say that I picked up one of these original K5 amps on OfferUp for only $40.

I have an old X5 2nd Generation that I am docking with the K5.

It sounds damn good. It's small enough to leave on my couch's side table or my bed's nightstand. The X5 DAC integration works with both my laptop and Android phone. I am using medium gain with my Aeon Flow Open headphones and the sound is powerful, clean, with very good bass slam. I used to own an Atom and like the K5 more for a few reasons: the middle gain setting, better build quality, better volume dial and better channel matching (maybe this is not the case on all Atoms but mine had really bad channel matching on low volumes)

This one is a winner. If you have a Fiio product that can dock with it absolutely buy one of these, espceially at the price they are going for in 2019!

if i use the x5iii on the dock, can it be used as a standalone DAC for my PC to drive active speakers? in this case, can i use the balanced line out to the balanced input on the speaker? would this be a reliable long term solution?
 

nintendoeats

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if i use the x5iii on the dock, can it be used as a standalone DAC for my PC to drive active speakers? in this case, can i use the balanced line out to the balanced input on the speaker? would this be a reliable long term solution?

The answer to all of these questions should be yes. I have never used the balanced outputs on mine, but what you are describing is one of the use-cases the K5 was designed for.
 
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