FIIO Warmer R2R DAC (with tube buffer)

[solderdude]

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Did you order one?
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Of course not as I am not interested in 'poorer signal fidelity' and have my audio gear already sorted anyway.
My gear sounds great and does not need to sound 'warmer', 'smoother', nor 'colder' nor 'more analytic' in any kind of way and if it is needed, for some recordings, a tone control is all I need.

 

[oleg87]

I was with you until the last ...

'vast majority' , 'isn't always' , ' usually easily', 'probably would be'

I think this is where there is a 'kind of permanent buck passing' that goes on here!

It's a big world out there and it would be silly to speak in absolutes... but one absolute I will absolutely stand by is that, between illusory differences and "possible but unlikely" discernable differences, the smart money is always on the former.

 

[Sliphorn]

Of course not as I am not interested in 'poorer signal fidelity' and have my audio gear already sorted anyway.
My gear sounds great and does not need to sound 'warmer' nor 'colder' nor 'more analytic' in any kind of way and if it is needed, for some recordings, a tone control is all I need.

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Uh, yeah. I was yankin’ yer crank, my man.
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[solderdude]

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Uh, yeah. I was yankin’ yer crank, my man.
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That's what emoticons like this: are for.

 

[Sliphorn]

That's what emoticons like this: are for.

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You always have the last word.
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[SMen]

This has been the case for ages already (tubes and its mysteries and filterless DAC designs).
Other things that gets the blood boiling is cables, mains cables, tweaks (the snake-oil kind) and ignorance disguised as 'knowledge'.
In fact ... the whole audio industry is filled with mostly nonsense and myths.

The combination of R2R and tubes was always expensive though or was not combined.
FiiO made it affordable and added a nice design + real swinging needles in the process + XLR + RCA out.
What's not to like.

It is actually a relief to me that cables, mains cables, and even most DACs for most of us, or me at any rate, have been relieved of snake oil.

I tried a Topping Centaurus but sent it back because of how it seemed to soften the life out of 24 bit 192 masters ... but now I am thinking its settings might have been making it default to NOS. I never checked, but I could understand a high frequency roll off ... but not the lack of dynamics. Made no sense.

But had I had more time I might have found out the reason.

Nothing to do with the FiiO warmer ... just a philosophical musing as I depart! I might actually get into measuring with that software sometime, and someone mentioned Delta something I think ... I will look back and thank them tomorrow. Late here.

 

[foden2025]

I have to admit, I'm not a fan of the way they added tubes in here. I got it mainly for the R2R NOS option and the VU meter and tube buffer is a bonus since I have the same tubes in my preamp and in some backup boxes. I tested a 6N23P in there and just replacing them and removing the clips and the choice of that weird horizontal layout is just not user friendly, I can't confirm there is massive difference if there is at all (some treble extension if I'm being subjective). Now if you choose tubes and run them at lower voltage to keep distortion down and heat as well, what's the point anyway just to box check that it has tubes? Also with tubes I usually prefer the 60 seconds warmup that a BAT preamp has to get the tubes to stable voltage. I still like the sound from this DAC, NOS for higher sample rates with only dithering and for PCM 44Hz upsampling using HQPlayer.

 

[mhardy6647]

Lying is correct.
Just like there are optical illusions and the brain 'fills-in' a lot of 'information' aspects like sight, touch and hearing are easily 'fooled' and are making things up.
We just don't realize it. The brain is simply wired that way.


Judging from the info from FiiO and their R2R section as well as what tube buffers do it will certainly measure 'horrible' when it concerns signal fidelity.
But this isn't designed for the measurement crowd and purposely engineered that way.
Of course all (filterless) DACs (R2R and DS) are designed for this purpose as well as gear with tubes is designed for that.
And there is plenty of that around.
Add meters and you have a hit.

It's a good thing that our hearing does not find those types of distortion objectionable. Some even like it. The sweet little lies...

Indeed. Consider the visual blind spot. Not a metaphor; we all have one in each eye. It's straightforward to demonstrate its presence, but absent a deliberate "study" to call attention to it, one's never aware of it.

Find Your Blind Spot!

A visual science project from Science Buddies

www.scientificamerican.com

 

[solderdude]

I tried a Topping Centaurus but sent it back because of how it seemed to soften the life out of 24 bit 192 masters ... but now I am thinking its settings might have been making it default to NOS.

NOS (filterless) DACs do not have any audible roll-off with 192kHz files. Even 88.2kHz files have no audible roll-off.

I tested a 6N23P in there

6N23P, ECC88, E88CC, 6922 and 6DJ8 are all usable in there but given the cathode follower configuration there won't be a big difference.
It is not recommended to use ECC82, 83 and 85 (and its variants) in there. Not enough anode voltage available for those.
Also can't use 12V heater tubes.
Besides the 'effect' of the tubes (decreasing amplitude of harmonics which are mainly lower order) is completely nullified by the poorly executed R2R harmonic 'spray'.
This is because they use (I assume not selected) 0.1% resistors where to get decent performance they should have used 0.01% (or better) resistors.
The usual R2R converters use those but cost more.

The only sensible reason to buy it is the looks and above all the swinging meter needles.
When one wants to hear what 'R2R' can do there are much better options.
When one wants to play with tubes there are better options with (more audible) tube-ness in it.
The 'NOS' can be defeated (using the OS function or software upsampling 4x) but the non-linearity of the converter and tubes cannot be bypassed.

Fortunately the device is good enough to give 'pleasant sound'.

Don't get me wrong I am not a FiiO hater... on the contrary.
I love (and own) two of their DAPs and absolutely love their JT7 and (modified FT13)... in fact listening to the modified FT13 on X3-II as I am typing (through a SS headphone amp).

 

[mhardy6647]

Also can't use 12V heater tubes.

There is that.

 

[SMen]

NOS (filterless) DACs do not have any audible roll-off with 192kHz files. Even 88.2kHz files have no audible roll-off.

That is a good point, but I'm pretty sure the 'auto' setting in the Centaurus was doing something with the dynamics when auto-switching to NOS that I did not like - could not have been anything to do with roll off - I preferred OS for some reason.

Nobody here is reporting a less dynamic sound with the FiiO warmer though when switching to NOS... great article here by Archimago from way back in 2018 on NOS vs OS - plus ca change.

 

[pkane]

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You always have the last word.
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And since @solderdude's words (first or last) are usually wise and carry lots of useful information, personally, I'd say it's worth listening to him

 

[Sliphorn]

And since @solderdude's words (first or last) are usually wise and carry lots of useful information, personally, I'd say it's worth listening to him

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Please pay attention.

My response to him was about his mild chastisement of me for not using emoticons because he did not have the savvy to pick up on me giving him a razz. Gimme a break. For him it must be good to be the king, eh?
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[pkane]

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Please pay attention.

My response to him was about his mild chastisement of me for not using emoticons because he did not have the savvy to pick up on me giving him a razz. Gimme a break. For him it must be good to be the king, eh?
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And you keep ignoring emoticons. Please pay attention, one was used in my post for a reason.

 

[Sliphorn]

And you keep ignoring emoticons. Please pay attention, one was used in my post for a reason.

And you keep ignoring emoticons. Please pay attention, one was used in my post for a reason.

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Methinks not. Weaseling your way out, pal. Why don’t you TELL me instead of using a lazy emoticon that means what exactly? Or will you suggest that I don’t have the savvy to interpret your laziness.
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[pkane]

Methinks not. Weaseling your way out, pal. Why don’t you TELL me instead of using a lazy emoticon that means what exactly? Or will you suggest that I don’t have the savvy to interpret your laziness.
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it’s about nonverbal communication. If you don’t understand a language, learn it rather than demanding that others explain it to you.

 

[Jeromeof]

So bass response is amplifier input resistance dependent so best to only use headphone amps or pre-amps with Rin > 10kohm.
Mystery seems solved.

So, I didn't have a lot of time today - but I did measure the FiiO Warmer with my Cosmos ADCiso with different input resistances - unfortunately I am not sure how to go beyond 3.8Kohm (10V) with the Cosmos ( I haven't yet bought the scalar ) but as you can hopefully see below as I varied the switches on the bottom of the ADCiso there was less roll-off - so I would say as @solderdude mention a pre-amp > 10k ohms would be linear (or very close):

As you can see in OS mode (@ 48Khz ) the treble roll-offs pretty early, while with NOS it be linear to almost 20khz.

I thought I would make an attempt at measuring the THD+N / SINAD in NOS mode:

So, 0.026% is about 72 SINAD - so I think this is similar to the K11R2R.

If I get some more time next week I will spend some more time measuring the Warmer.

 

[solderdude]

Yep, confirms the output capacitance to be the culrprit for the bass roll-off.
Also why FiiO specifies the Warmer with a 10k load as there is no audible roll-off in that case.

Are you using balanced out by chance ?
That would explain some math and the harmonic profile (which is anything but 'tubey')

 

[LumiAudioNut]

So, I didn't have a lot of time today - but I did measure the FiiO Warmer with my Cosmos ADCiso with different input resistances - unfortunately I am not sure how to go beyond 3.8Kohm (10V) with the Cosmos ( I haven't yet bought the scalar ) but as you can hopefully see below as I varied the switches on the bottom of the ADCiso there was less roll-off - so I would say as @solderdude mention a pre-amp > 10k ohms would be linear (or very close):

View attachment 498661

As you can see in OS mode (@ 48Khz ) the treble roll-offs pretty early, while with NOS it be linear to almost 20khz.

I thought I would make an attempt at measuring the THD+N / SINAD in NOS mode:

View attachment 498663
So, 0.026% is about 72 SINAD - so I think this is similar to the K11R2R.

If I get some more time next week I will spend some more time measuring the Warmer

Thank you for sharing these valuable measurements.

Out curiosity, do you have any plans to post a follow on set of measurements after a few hundred hours of use? I would be interesting to see if any significant changes are observed.

-Lumi

 

[Jeromeof]

Yep, confirms the output capacitance to be the culrprit for the bass roll-off.
Also why FiiO specifies the Warmer with a 10k load as there is no audible roll-off in that case.

Are you using balanced out by chance ?
That would explain some math and the harmonic profile (which is anything but 'tubey')

Yes, I was using balanced outputs today as I had them handy - I need to tidy up my collection of cables I was looking for a suitable 2.5mm for the Cosmos which I know I have somewhere but couldn't find it earlier.

Out curiosity, do you have any plans to post a follow on set of measurements after a few hundred hours of use? I would be interesting to see if any significant changes are observed.

No I don't have plans at the moment. I was thinking of checking out which of my headphone Amps would avoid the bass roll off, looking at the specs I think the Schiit Midgard would work well but I think I would measure it. I personally hate the idea of 'synergy' as it gives subjective reviewers the opportunity of talking BS so it would be good / useful to indicate which amplifiers would technically work well with the Warmer R2R.

Note: I think that SINAD measurement I did is wrongly labelled - it is probably OS mode looking - I will do it again next week.