guddu478
Active Member
A rather unique “Tube buffered R2R Balanced DAC with VU meters” for little over 300$.
“If you are reading this post then I can safely say that you have some interest in R2R & Tube tech without being overly analytical about their objective measurements and parameters.”
R2R Tube DACs are not rare, what’s rare here is that this one does not cost over two grand $ like others, to say the least.
Most Audiophiles just swear by R2R and tube stuff. As they say, the tube character (by adding harmonic distortion) added by tube buffer might sound pleasing especially with certain mid-range focused music.
Some simply claim that R2R or tube products do not have high frequency details compared to others. I find it hard to agree with this statement as I neither see any issues with high frequencies in frequency response graphs (provided by Fiio on product page, added towards the end in the post) nor I see any changes in REQ & Dirac Live frequency captures at my place (which I simply did to compare with Wiim Ultra and verify).
R2R Warmer is Fiio’s newest R2R DAC, after K13 R2R. It is a R2R DAC with tube buffer stage and glorious large VU meters on front display.
Let us get the basic details out of the way here:
- 24 bit R2R DAC with Tube buffer, comes with imported 4 x JJ Electronics E88CC tubes/valves
- It has fully differential design which, in theory, should help towards eliminating noise & distortion
- Inputs: Optical, Coaxial and USB type C
- Outputs, Line Out: RCA (single ended) and XLR (balanced)
- Decoding Modes: Over Sampling (OS) and Non-Over Sampling (NOS) modes, selected by toggle switch on the back
- USB Operational Modes: UAC 1.0 & 2.0, selected by toggle switch on the back
- Built-in linear power supply (AC input), employs 46 watts rated toroidal transformer
*Note that it takes about 24 watts in operation.*
Please find more product details and specifications here:
https://www.fiio.com/WARMERR2R
*****
FiiO R2R WARMER - Build Quality & Aesthetics – Pure Vintage Charm
*****
Stunning vintage look, trust me or not but Fiio’s recent releases are highly satisfying with their looks & aesthetics.
Build is excellent, solid & heavy as it should be to hold and operate the components safely.
Beautiful large front display with VU meters, lightened by LEDs with warm amber color.
Case has lots of grille vents for ventilation necessary to help maintain temperature.
You can see relatively chunky toroidal transformer and other components through vents… You can easily realize the quality of the components when get a glimpse of inside.
*****
DAC Operation modes - OS vs NOS
*****
Over Sampling (OS) Mode - Standard mode used by a DAC to construct a technically more accurate analog signal applying upsampling (384 KHz in this case), digital filtering, shaping, etc.
Non Over Sampling (NOS) Mode - No additional processing applied after Digital to Analog conversation
*Note that OS/NOS modes are not specific to R2R DACs, Delta-Sigma DACs have same modes as well.
While Objectively, OS mode is required to get more accurate noise/distortion/shaped/frequency-artifact-free signal achieving higher noise & distortion numbers, subjectivists prefer NOS mode often arguing that its pure or unaltered output.
*****
Here is the setup I have in action
*****
TV --> optical_out --> Wiim Ultra --> optical_out --> Fiio R2R Warmer --> RCA_out --> RCA_Switch --> 3e A7 Amplifier
TV --> optical_out --> Wiim Ultra --> RCA_out --> RCA_Switch --> 3e A7 Amplifier
Please note that the further details I am going to mention here are based on experience and opinion using Fiio R2R Warmer in the mentioned setup.
*****
FiiO R2R WARMER - in action
*****
??? – Does Tubes do anything in this DAC?
Sure, the tubes here definitely add higher order harmonic distortion. There are a few measurements available that clearly show it.
??? – Which mode is better – OS or NOS
Very difficult to say as sounded identical to me (and friends) in blind listening.
We found it absolutely COHERENT and SUPER NON-Fatigue to listen to.
Differences – Sure! There may be differences, but I could not hear any. May be those are for measurement instruments!
***
USB Operation modes – UAC 1.0 & 2.0
***
UAC 1.0 a.k.a. USB Audio Class 1.0
Wide compatibility for older devices, different OS platforms and such that cannot use specific USB drivers.
Uses lower bit rate.
Operating on Windows 11 – UAC 1.0
Worked without any issues on Windows 10, Windows 11, nVidia Shield Pro (android 11), Google TV box (android 14) and iPhone.
Note the max bitrate or audio resolution supported.
UAC 2.0 a.k.a. USB Audio Class 2.0
Provides higher bitrate and audio resolution but sometimes need specific device drivers for optimal performance.
Windows 11 – UAC 2.0 – Without Fiio USB Drivers
Worked without any issues on Windows 10, Windows 11, nVidia Shield Pro (android 11), Google TV box (android 14) and iPhone.
Fiio USB Driver
Windows 11 – UAC 2.0 –with Fiio USB Drivers
ASIO works nicely as well for bit streaming:
*****
R13 R2R DAC - Sound Quality
*****
The best I can describe is "absolutely COHERENT, engaging and easy to listen to".
I have the same experience with my Fiio K13 R2R DAC and Denafrips Ares (at friend’s). It’s all very smooth and laidback kind of sound in my experience.
Attention does not go to high details playing in the song as you would normally notice in a song (especially if switch from something like Topping D90, E50, Wiim Ultra, etc.).
Tube Buffer and R2R DAC function the way being intended, and so as the gorgeous VU meters on front display with glowing amber LED.
Does Vocals sound good - Sure, I would say Vocals and instruments sound amazing.
??? Did I try blind test with SPL level matched with other DACs - Sure I did
??? But what about SINAD
Looking at the specs provided by FIIO, the SINAD comes out about -65dB which seems to be dominated by harmonics.
Here are the published parameters & specs:
?? Does it produce any hiss/noise when playing or on idle when nothing is playing
Absolutely nothing, I found it dead silent.
??? Any pop or other noise on power ON/OFF <<<<< Please Note>>>>>>
Yes, there is faint pop/noise on power ON/OFF.
You can always prevent it going to your speakers if you think it might be harmful by powering on amplifier after you power on the DAC and likewise power off the amplifier before powering off the R2R Warmer DAC.
??? Does it run hot
It has 4 tubes which will surely generate heat but nothing that I would be worried about.
Keep it in ventilated space and you are good to go.
What would I have liked more in R2R Warmer?
While I normally look at a product for what it is rather than what it isn't. However, the following would have enhanced user experience:
* 12v Trigger and/or signal sensing auto-ON/OFF
* A dimmer for front display LEDs (would not imagine a turn off option though)
* LED color options
As as side note, I would not worry about the printing mistake on the box
Summarizing all the thoughts........
I believe Fiio R2R WARMER is a keeper. It has great build, stunning looks and all audiophile loved techs.
Very likable coherent, balanced and smooth sound character makes it easy to listen to. It is more apparent after listening for a day or two and then switch to another DAC.
If you are into tubes then it might be a loss not to try this one.
“If you are reading this post then I can safely say that you have some interest in R2R & Tube tech without being overly analytical about their objective measurements and parameters.”
R2R Tube DACs are not rare, what’s rare here is that this one does not cost over two grand $ like others, to say the least.
Most Audiophiles just swear by R2R and tube stuff. As they say, the tube character (by adding harmonic distortion) added by tube buffer might sound pleasing especially with certain mid-range focused music.
Some simply claim that R2R or tube products do not have high frequency details compared to others. I find it hard to agree with this statement as I neither see any issues with high frequencies in frequency response graphs (provided by Fiio on product page, added towards the end in the post) nor I see any changes in REQ & Dirac Live frequency captures at my place (which I simply did to compare with Wiim Ultra and verify).
R2R Warmer is Fiio’s newest R2R DAC, after K13 R2R. It is a R2R DAC with tube buffer stage and glorious large VU meters on front display.
Let us get the basic details out of the way here:
- 24 bit R2R DAC with Tube buffer, comes with imported 4 x JJ Electronics E88CC tubes/valves
- It has fully differential design which, in theory, should help towards eliminating noise & distortion
- Inputs: Optical, Coaxial and USB type C
- Outputs, Line Out: RCA (single ended) and XLR (balanced)
- Decoding Modes: Over Sampling (OS) and Non-Over Sampling (NOS) modes, selected by toggle switch on the back
- USB Operational Modes: UAC 1.0 & 2.0, selected by toggle switch on the back
- Built-in linear power supply (AC input), employs 46 watts rated toroidal transformer
*Note that it takes about 24 watts in operation.*
Please find more product details and specifications here:
https://www.fiio.com/WARMERR2R
*****
FiiO R2R WARMER - Build Quality & Aesthetics – Pure Vintage Charm
*****
Stunning vintage look, trust me or not but Fiio’s recent releases are highly satisfying with their looks & aesthetics.
Build is excellent, solid & heavy as it should be to hold and operate the components safely.
Beautiful large front display with VU meters, lightened by LEDs with warm amber color.
Case has lots of grille vents for ventilation necessary to help maintain temperature.
You can see relatively chunky toroidal transformer and other components through vents… You can easily realize the quality of the components when get a glimpse of inside.
*****
DAC Operation modes - OS vs NOS
*****
Over Sampling (OS) Mode - Standard mode used by a DAC to construct a technically more accurate analog signal applying upsampling (384 KHz in this case), digital filtering, shaping, etc.
Non Over Sampling (NOS) Mode - No additional processing applied after Digital to Analog conversation
*Note that OS/NOS modes are not specific to R2R DACs, Delta-Sigma DACs have same modes as well.
While Objectively, OS mode is required to get more accurate noise/distortion/shaped/frequency-artifact-free signal achieving higher noise & distortion numbers, subjectivists prefer NOS mode often arguing that its pure or unaltered output.
*****
Here is the setup I have in action
*****
TV --> optical_out --> Wiim Ultra --> optical_out --> Fiio R2R Warmer --> RCA_out --> RCA_Switch --> 3e A7 Amplifier
TV --> optical_out --> Wiim Ultra --> RCA_out --> RCA_Switch --> 3e A7 Amplifier
Please note that the further details I am going to mention here are based on experience and opinion using Fiio R2R Warmer in the mentioned setup.
*****
FiiO R2R WARMER - in action
*****
??? – Does Tubes do anything in this DAC?
Sure, the tubes here definitely add higher order harmonic distortion. There are a few measurements available that clearly show it.
??? – Which mode is better – OS or NOS
Very difficult to say as sounded identical to me (and friends) in blind listening.
We found it absolutely COHERENT and SUPER NON-Fatigue to listen to.
Differences – Sure! There may be differences, but I could not hear any. May be those are for measurement instruments!
***
USB Operation modes – UAC 1.0 & 2.0
***
UAC 1.0 a.k.a. USB Audio Class 1.0
Wide compatibility for older devices, different OS platforms and such that cannot use specific USB drivers.
Uses lower bit rate.
Operating on Windows 11 – UAC 1.0
Worked without any issues on Windows 10, Windows 11, nVidia Shield Pro (android 11), Google TV box (android 14) and iPhone.
Note the max bitrate or audio resolution supported.
UAC 2.0 a.k.a. USB Audio Class 2.0
Provides higher bitrate and audio resolution but sometimes need specific device drivers for optimal performance.
Windows 11 – UAC 2.0 – Without Fiio USB Drivers
Worked without any issues on Windows 10, Windows 11, nVidia Shield Pro (android 11), Google TV box (android 14) and iPhone.
Fiio USB Driver
Windows 11 – UAC 2.0 –with Fiio USB Drivers
ASIO works nicely as well for bit streaming:
*****
R13 R2R DAC - Sound Quality
*****
The best I can describe is "absolutely COHERENT, engaging and easy to listen to".
I have the same experience with my Fiio K13 R2R DAC and Denafrips Ares (at friend’s). It’s all very smooth and laidback kind of sound in my experience.
Attention does not go to high details playing in the song as you would normally notice in a song (especially if switch from something like Topping D90, E50, Wiim Ultra, etc.).
Tube Buffer and R2R DAC function the way being intended, and so as the gorgeous VU meters on front display with glowing amber LED.
Does Vocals sound good - Sure, I would say Vocals and instruments sound amazing.
??? Did I try blind test with SPL level matched with other DACs - Sure I did
??? But what about SINAD
Looking at the specs provided by FIIO, the SINAD comes out about -65dB which seems to be dominated by harmonics.
Here are the published parameters & specs:
?? Does it produce any hiss/noise when playing or on idle when nothing is playing
Absolutely nothing, I found it dead silent.
??? Any pop or other noise on power ON/OFF <<<<< Please Note>>>>>>
Yes, there is faint pop/noise on power ON/OFF.
You can always prevent it going to your speakers if you think it might be harmful by powering on amplifier after you power on the DAC and likewise power off the amplifier before powering off the R2R Warmer DAC.
??? Does it run hot
It has 4 tubes which will surely generate heat but nothing that I would be worried about.
Keep it in ventilated space and you are good to go.
What would I have liked more in R2R Warmer?
While I normally look at a product for what it is rather than what it isn't. However, the following would have enhanced user experience:
* 12v Trigger and/or signal sensing auto-ON/OFF
* A dimmer for front display LEDs (would not imagine a turn off option though)
* LED color options
As as side note, I would not worry about the printing mistake on the box
Summarizing all the thoughts........
I believe Fiio R2R WARMER is a keeper. It has great build, stunning looks and all audiophile loved techs.
Very likable coherent, balanced and smooth sound character makes it easy to listen to. It is more apparent after listening for a day or two and then switch to another DAC.
If you are into tubes then it might be a loss not to try this one.
