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FX-Audio Tube 02 Pro Review (Headphone Amp)

Rate this product:

  • 1. Poor (headless panther)

    Votes: 72 40.0%
  • 2. Not terrible (postman panther)

    Votes: 63 35.0%
  • 3. Fine (happy panther)

    Votes: 37 20.6%
  • 4. Great (golfing panther)

    Votes: 8 4.4%

  • Total voters
    180

Saponetto

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Old Southern Italy
Not terrible, considering that this device has to be defined as a pleasant "audio device" instead of a "HiFi device".
Not disregarding on its philosophy at all, I had and still have so much fun with these little things.
I simply do not use these as part of my listening chain.
Having multiple inlets and headphone sockets, I could easily see it as a nice part of my "office music machine".
 

hoverdonkey

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Oct 6, 2019
Messages
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37
The amp simply does what audiophiles are asking: deliver them distortion and tons of it.

Masterful.

ezgif-4-9a3cd00f78.gif
 

CedarX

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Amir's listening tests puzzle me (I am absolutely not questioning them): The Tube 02 Pro sounded "fine" on the high-impedance HD-650 at low volume. The measurements show distortion to decrease (a bit...) at higher load impedance. The LCD-XC and Ether-CX are more efficient than the HD-650 and exceptionally clean--no HP-added distortion.
Did I misunderstood something... or how come the HD-650 is not the worse sounding headphone here? Is it related to the (relative) lack of sub-bass of the HD-650? Are the HD-650 own distortions somehow "canceling" the Tube 02 Pro distortions, or do they impact/reduce IMD distortions making the whole thing more listenable? Does the phase response variability of the HD-650 play a role?

I think one could mimic the Tube 02 Pro distortion profile in the (excellent) Distort software (https://distortaudio.org/) and explore the audible impact on different HPs (I just assigned myself one more educational project!!!). BTW, even if the Tube 02 Pro is a fair value IMO (as long as you understand what you're getting into), Distort may be a better investment: it's actually free/donation, though it certainly requires a significant time investment. DSP may be another path to mimic and explore these distortion profiles, but implementing distortions onto a DSP does not seem trivial...
 
Last edited:

hoverdonkey

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Oct 6, 2019
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What does Euphonic even mean?… I have a Freya+ Tube preamp. It sounds really good. Does it sound different thans the other modes? I wouldn’t know, because it don’t have the same gain, but it doesn’t sound distorted, tubes don’t have to. It does have measurably higher THD than the other SS stage tough. It don’t matter to me, it’s a good sounding preamp tube or not.

euphonic, adj.
†a. Well sounding, agreeable to the ear; = euphonious adj. Obsolete.
b. Conformable to the laws of euphony.
(OED)

:)
 

PeteL

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Amir's listening tests puzzle me (I am absolutely not questioning them): The Tube 02 Pro sounded "fine" on the high-impedance HD-650 at low volume. The measurements show distortion to decrease (a bit...) at higher load impedance. The LCD-XC and Ether-CX are more efficient than the HD-650 and exceptionally clean--no HP-added distortion.
Did I misunderstood something... or how come the HD-650 is not the worse sounding headphone here? Is it related to the (relative) lack of sub-bass of the HD-650? Are the HD-650 own distortions somehow "canceling" the Tube 02 Pro distortions, or do they impact/reduce IMD distortions making the whole thing more listenable? Does the phase response variability of the HD-650 play a role?

I think one could mimic the Tube 02 Pro distortion profile in the (excellent) Distort software (https://distortaudio.org/) and explore the audible impact on different HPs (I just assigned myself one more educational project!!!). BTW, even if the Tube 02 Pro is a fair value IMO (as long as you understand what you're getting into), Distort may be a better investment: it's actually free/donation, though it certainly requires a significant time investment. DSP may be another path to mimic and explore these distortion profiles, but implementing distortions onto a DSP does not seem trivial...
I am not sure what you mean, there is less distortion at 300 ohms that at 20, this graph shows that, so normal than the highest impedance would be the less distorted? Sure you would have to be past 100 mV for it to matter, but none of those are very efficient, they are not very unneficient neither, but Amir listen loud.
1645637560551.png
 
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don'ttrustauthority

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Conclusions
I see a price of $79 and read "tubes" and I immediately equate that to junk. Such was not the case here. The casework is very nice, as well as some of the measurements. The amp simply does what audiophiles are asking: deliver them distortion and tons of it. The common misconception is that this distortion is either inaudible or euphonic. Neither was the case in my listening tests. Before you say, "but your test was not blind," I will remind you that neither are all the remarks about the sound being euphonic! :)

If you want a very low cost way to get a tube-based headphone amp/pre-amp that has good effort behind it, here is your chance with FX-Audio Tube 02 Pro. I am not in that camp so can't recommend it.


Well we say we want tube euphonic distortion, we're looking at -72 / 90 range, not -40. That's junk.
 

CedarX

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I am not sure what you mean, there is less distortion at 300 ohms that at 20, this graph shows that, so normal than the highest impedance would be the less distorted?
OK, my bad, I was confused by the statement "Distortion increases with lowering load" and understood "...with lowering impedances". I should have paid more attention to the curve colors and legend on the graph.
 

Saponetto

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May 19, 2021
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Old Southern Italy
...Perhaps is the actual problem that the distortion level of this little thing is too low to be "tubey" and at same time too high to be "accurate"? :)
 

pseudoid

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Why bother eating bugs when you can just get a good bowl of soup for the same price without any flies in it.
LOL!
It's all about the protein, which should never be confused with distortion products...;)
 

DonR

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I despise products with black (or white) solder mask as it makes them very difficult to service. Not that anyone will likely service an $80 tube amp.
 

JaMaSt

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Joined
Sep 14, 2021
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Location
Vancouver, WA
Because people believe in 'tube magic' and subjective reviewers are always positive of anything ancient.
I've wondered about this. Doesn't the presence of even "non-audible" 2nd and 3rd harmonics still consume power that could otherwise be used to power the "audible" sound? I believe this is difference that people "hear" with tube amps - not distortion per se, but rather an adjustment to the power distribution across the entire audible range of frequencies.

I remember using a hybrid tube amp with my Sennheiser HD800 and it really tamed some of the shouty-ness of the highs - it made them much less fatiguing over time. I'd never use a tube amp on anything less than 150 ohms and at 300, like the Senns, there was no aspect of the sound that could be described as "distortion".
 

solderdude

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Doesn't the presence of even "non-audible" 2nd and 3rd harmonics still consume power that could otherwise be used to power the "audible" sound?

It is too low in level to be heard. Besides, the same characteristic can be had from FETs and if these were so musical wouldn't all SS amps have FETs?
I remember using a hybrid tube amp with my Sennheiser HD800 and it really tamed some of the shouty-ness of the highs

The 'shoutyness' of the HD800 is in the 5.5kHz region. Some tube(hybrids) do have audible roll-off in the upper treble but not in the area where the HD800 is ' hot' (5 - 12kHz range).
If it were harmonics that would be reaching audible levels then it would be music in the 2.5kHz -6kHz range (2nd harmonics) that would only aggrevate the shouty-ness so it can't be the added harmonics.

Only the bass (having higher amplitude) would add harmonics but they are too low in level (and will be masked by bass overtones) to really make an audible difference.
I have no doubt you heard what you heard but am pretty confident it is not of electrical origin.
 

iMickey503

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I'm just glad China could make it so anyone can afford to buy this and test it out and fiddle around with it to see what the tube experience is all about. Anything that gets people into audio is a good thing in my book.

Sooner or later, there will end up being a following for these guys, and someone is going to do some modifications on it to try to eek a bit more out of it. So I see it as the tuner scene for cars. You take something that is okay. And you make it something better.

That kind of thinking is how great audio products came to light in the first place.

HOWEVER.
Just like one other person said.
1645723606211.png
They need to hire an Italian.
They almost got the design right if not for the silk screening.

1645723833947.png
Why?

See how much better it looks the less "Microsoft" it gets? Save the money on the printing.
People who buy this stuff are not impressed by it. Its like adding a wing to a car that just takes away from the great lines of a car.
1645723993009.png




A better look is something like this. K.I.S.S. Simple. Elegant. Proper.
1645724600267.png




How to do it right?
magni-heresy-front-1920-NL(1).jpg

Simply. beautiful.

And lets be honest. Why do people spend 5k on a headphone amp? Because it makes you feel good using it! You come home and you look at it, and it reminds you that someone put their soul into it. You can almost feel the design of the artist who wanted to tell you how good the music they played on the Amp made you them feel.
mabhpa-14.jpg

manley-absolute-headphone-6-3000px.jpg

manley-absolute-headphone-2-3000px.jpg

Just look at those Knobs!
1645725356860.png

And notice the print and font. Its not perfect. Its just artistic.
mabhpa-black-on-white-4.jpg


Its not even finished that well. But its the ART and the WAY they did it that makes it what it is. They are not pretending. They simply put it out there and do it even by hand. It has a human touch to it. All these things help you connect to the experience and music.
1645725588883.png



Now compare this unit I got for my Kid. The layout is retarded. But they make no apologies about its design and it's simply just there. The tubes don't even match each other. No frills on printing. Just what you need. And once you plug it all in? You won't ever see the IN and OUT nor "Volume" . They just said:
------- WE are going to make a TUBE Headphone amplifer! Screw all the crap that does not matter to the sound. Lets make it simple, clean & easy to use and call it a day! ------
.
71Lt+M9uXsL._AC_SL1200_.jpg


More evidence of it here:
1645726399583.png


Its simple. No trying to be what it is not. Its honest. And they want you to have fun with it.
1645726698458.png


They even go as far as telling you what tubes you can roll with it. No where do they mention some Mythical BS about what it is not. And I like that.
1645727133643.png


FX-Audio IMO?

1. Drop the FX-AUDIO- and go to FXA. Save that for the back of the unit. IN SMALL TEXT. If you want to name brand it? Do it right.
fxa-logo-copy.png

2. Drop the "PRO". Its like "Heavy Duty Batteries"
1645727708956.jpeg
This is what "PRO" means in the western market..

3. Simplify the design and get rid of the text. No one uses DOS anymore...Everyone uses Icons today. And you wont have to make custom prints in other languages. You are in a WORLD market. Start acting like it.
vehicle-instrument-cluster-warning-lamps-vector-30164577.jpg
1645728008476.jpeg


4. Drop the "High Quality" BS... You sound like a a politician or car salesman. You already know what the stigma of having The Stereotype of items coming from China already is.
made-in-china-quality-meme-39370076.png


Use something like this:
KerimsaKnit-china.png
Make it a POINT that you take PRIDE in your gear and the people who make it.
You have a beautiful way of writing your characters so exploit that.
image011.png
<<<Do more of this. Less ROBOT English font.

5.
Your making a product for people who listen to music. They know where their volume is at. So save the money on the crappy silk screening. Just go less is more. Its the MOST important part of your product as its the MAIN thing they are going to feel. Go with a Simple Dimple. Its elegant. Its way better looking. And costs less labor too.
1266161_sa.jpg
volume-speaker-concept-with-hand.jpg

You could even use Rubber feet at less then a Penny each as the knob and give it a great feel at a Budget price! It will set it apart. There are already to may of these items on the market. You have to set yourself apart.

These from china cost me with free shipping less then $4.00. I bet you can get these for less then 5 cents there in quantity or less. This would make your product stand out. Hell, I bet you could get used ones and call them "Green" and market that too!.
shopping

I'm just saying. There is a LOT more that could be done to make this a stand out instead of another item that there are many of already. With the downturn in the world economy? You have to stand out. Price alone is no longer what works in a flooded crowded market.

Fx Audio already makes cool stuff. But its getting tired and old seeing the same old stuff year after year. You got the meat and potatoes, you just need to add the Tabasco!

Respectfully,
The people who buy your gear.
 

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