• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Review and Measurements of Fiio K5 Pro

prakosza

New Member
Joined
Sep 24, 2019
Messages
3
Likes
0
Hmm... I'm kinda a noob so I hope I won't sound stupid asking that but what does it mean when you say that at 1 volt sinbad is better? I can understand that means it plays more quite than on 2 volts but what it means it practice? Oh and would it be possible (if it even makes any seans to check sinbad on usb -> hp)?
 

daftcombo

Major Contributor
Forum Donor
Joined
Feb 5, 2019
Messages
3,687
Likes
4,068
Hmm... I'm kinda a noob so I hope I won't sound stupid asking that but what does it mean when you say that at 1 volt sinbad is better? I can understand that means it plays more quite than on 2 volts but what it means it practice? Oh and would it be possible (if it even makes any seans to check sinbad on usb -> hp)?

"Sinbad" is better means that THD+Noise is lower. If you play your tunes at -6dB max (via a hard limiter in Foobar2000 for instance, of setting Windows volume a bit under 100), you will have less THD+N hence better sound. Not that you would hear a difference though.
 
Last edited:
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,384
Location
Seattle Area
Hmm... I'm kinda a noob so I hope I won't sound stupid asking that but what does it mean when you say that at 1 volt sinbad is better? I can understand that means it plays more quite than on 2 volts but what it means it practice? Oh and would it be possible (if it even makes any seans to check sinbad on usb -> hp)?
As long as you don't play as loud, you would get the lower distortion that lower output represents. For standardization, I use 2 volt but that would be louder than you would normally use here.
 

prakosza

New Member
Joined
Sep 24, 2019
Messages
3
Likes
0
"Sinbad" is better means that THD+Noise is lower. If you play your tunes at -6dB max (via a hard limiter in Foobar2000 for instance, of setting Windows volume a bit under 100), you will have less THD+N hence better sound. Not that you would hear a difference though.
As long as you don't play as loud, you would get the lower distortion that lower output represents. For standardization, I use 2 volt but that would be louder than you would normally use here.
Thank you for your answers :) Does 2v output means that it's always on the same loudness level on every device or is there any other parameter of electricity that determines loudness other than voltage?

Edit:
To clarify if 2v will always mean the same level of loudness coming from device devices into for example the same pair of headphones.
 

zermak

Senior Member
Joined
Jun 2, 2019
Messages
372
Likes
251
Location
Italy
@prakosza
2 volts (RMS) is the output you will have when you play a sine wave (or audio file or anything else) that reaches 0dBFS so it means in reality it will not happen frequently if you use properly mastered audio files/music. Maybe some very compressed songs, cause of the DR war, reach it more frequently.

Side note. When you will play it through an amplifier (mainly for headphone) you will surely lower the output voltage before it reaches the amp stage because of the nature of amp (or we would name it differently) and its gain.

I am not an expert and I am sure someone else will explain it more technically.
 
Joined
Aug 18, 2019
Messages
14
Likes
8
Hi amir, for DAC/amp combo units wouldn't it be more appropriate to measure usb->headphone out since this is their main use? In this case isn't there a possibility that it'll measure worse than if you added the individual DAC and amp measurments.
 

mkawa

Addicted to Fun and Learning
Joined
Sep 17, 2019
Messages
788
Likes
695
he did that. the headphone out graphs in the OP are from usb to HP out. the second set of measurements further along in the thread are from line in to headphone out. the measurements don't change much because the dac has been designed to output signal that just barely out-resolves the HP amp. adding more resolution via the line in doesn't really help because the HP amp is the distortion bottleneck

this is also why it's 149$ prime shipping on amazon right now. for that you get a dac, HP amp and 15v psu capable of putting 1W into a pair of headphones.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,384
Location
Seattle Area
Does 2v output means that it's always on the same loudness level on every device or is there any other parameter of electricity that determines loudness other than voltage?
It will play at the same volume on every device if they all have 2 volt output.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,384
Location
Seattle Area
Hi amir, for DAC/amp combo units wouldn't it be more appropriate to measure usb->headphone out since this is their main use?
That is exactly what the measurements are. If there is a DAC in there, I always use USB unless I say otherwise.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,384
Location
Seattle Area
Edit:
To clarify if 2v will always mean the same level of loudness coming from device devices into for example the same pair of headphones.
This is not correct for DACs. You would have an amplifier after them and that would determine how loud they get.
 

JohnYang1997

Master Contributor
Technical Expert
Audio Company
Joined
Dec 28, 2018
Messages
7,175
Likes
18,292
Location
China
Does using volume control built in improve performance at lower level??
 

mkawa

Addicted to Fun and Learning
Joined
Sep 17, 2019
Messages
788
Likes
695
oh, one correction, i think. the device uses an NJW1195A relay based single chip volume control. njw11985a is a resistance ladder analog domain attenuator, not a digital domain volume control (the ak4493's digital volume control is lossy).
 

scooter

Active Member
Forum Donor
Joined
May 12, 2019
Messages
139
Likes
51
It is the same as digital in since the DAC is not the limiting factor:

View attachment 34374

I did not try to mess with it and reduce the impact of the mains leakage so ignore that part.
As mentioned in the review, line out is not constant 2V. But why does it compromise DAC SINAD when it should be isolated from amplified headphone out?
Line out is supposed to be direct output from DAC before reaching amplifier section circuits, or am I wrong?
I guess optical in - line out would have the same measurement as usb in - line out?
 

Vovgan

Active Member
Forum Donor
Joined
Jan 9, 2019
Messages
188
Likes
346
Location
Moscow, Russia
Hi amir, for DAC/amp combo units wouldn't it be more appropriate to measure usb->headphone out since this is their main use?
That is exactly what the measurements are. If there is a DAC in there, I always use USB unless I say otherwise.

I think both @irrationophile and I understood your measurements in the same way. In the main review under "DAC measurements" you mentioned that it was for digital (USB?) in -> line out. “Line out” is not the same as headphone out - right? This Fiio has "line out" outputs on its rear panel.
After that you posted additional measurements for analog “line in -> headphone out”. Each of these two separate measurements produced almost identical SINAD of around 82. And these are the only two SINAD numbers that we see. But these are two separate sub-systems - DAC and amplification - so is it correct to assume that their combined SINAD (“USB in -> headphone out”) is around 76?

Or are your measurements in the main review actually for “USB in -> headphone out” rather than “USB in -> line out” as it is written there? If that is the case, if
the DAC is not the limiting factor
then the "DAC Audio Measurements" are actually "USB in, Headphone out Audio Measurements". Then from the fact that SINAD for “USB in -> headphone out” is virtually the same as analog “line in -> headphone out” we can deduce that SINAD for DAC alone is much better.

if you have two subsystems cascaded with each having a SINAD of 80, the resulting SINAD will be 74 dB. If one is 90 dB, it almost makes no impact on the total SINAD as the 80 dB one dominates.
 
Last edited:

prakosza

New Member
Joined
Sep 24, 2019
Messages
3
Likes
0
Well I'm not sure if it's even possible to check output of pure dac from this device as line output is already preamp.
 

Degru

Active Member
Joined
Feb 19, 2019
Messages
230
Likes
254
Location
Beaverton, OR
Only 990 into 30? My Fiio A5 does 880, and it's a portable unit that's not bogged down with a mediocre DAC.. :)
 
Joined
Aug 18, 2019
Messages
14
Likes
8
That is exactly what the measurements are. If there is a DAC in there, I always use USB unless I say otherwise.

I understand you use USB but from my understanding you are still measuring the DAC by itself (usb->lineout), then the Amp separately (line in->phone out)? Sorry if I'm wrong and misunderstood your testing procedure.
If I am correct, then what I was saying is the USB->phone out performance may be worse due to some anomaly or weird stuff going on internally when DAC and amp are working together. Another way to put it is that summing the performance of the DAC by itself and the amp by itself (e.g. SINAD of dac + amps distortion and noise) may show better (or worse) results than USB->phone out.
 
Joined
Aug 18, 2019
Messages
14
Likes
8
So everything under the 'headphone amplifier audio measurements' section of the review is USB in->phone out?
 
Joined
Aug 18, 2019
Messages
14
Likes
8
In the review he says under 'dac audio measurements' that he is measuring line-out, not headphone out. It's the first sentence.
 
Top Bottom