xDuoo XD05T Portable DAC and Tube Headphones Amplifier

[VSG]

The xDuoo XD05T is a versatile portable DAC/amp that outshines many desktop sources. It combines cutting-edge ESS DAC technology with vintage 1960s Soviet vacuum tubes to deliver a remarkable sound—clean, detailed, and enriched by the warm, full-bodied tones of tube amplification. With modern connectivity and a reasonable price, it's a compelling choice for audiophiles.

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[Wirko]

The tubes are not filled with gas. They are filled with vacuum, just like all general-purpose amplifier tubes.

 

[VSG]

The tubes are not filled with gas. They are filled with vacuum, just like all general-purpose amplifier tubes.

I blame an early morning writing session, clearly they are vacuum tubes as mentioned elsewhere in the review haha. Thanks for catching that, I've corrected it.

 

[Space Lynx]

Very interesting, never seen a portable tube amp before. Kind of neat. For that kind of money though, I'd rather keep saving for the Fiio K17 amp/dac coming out early next year, as I don't really need portable.

 

[VSG]

Very interesting, never seen a portable tube amp before. Kind of neat. For that kind of money though, I'd rather keep saving for the Fiio K17 amp/dac coming out early next year, as I don't really need portable.

Yeah, I would not recommend a portable tube amp as a starter set. It's more for someone who already knows they want something flavored to use with portable IEMs/headphones. This can be used on a desk too, but again you can get other options there if you only care about a stationary setup.

 

[HairyLobsters]

Seems like a majority of portable DAC companies are Chinese based.

 

[Ferrum Master]

The tubes are not filled with gas. They are filled with vacuum, just like all general-purpose amplifier tubes.

Can you actually fill something with vacuum?

To be fair, there are some gas filled tubes like the lovely regulator tube VR150.

 

[Wirko]

Can you actually fill something with vacuum?

Not easily. First it doesn't want in, then it wants out, then it succeeds, then the tube glows in blue, then it dies too early.

To be fair, there are some gas filled tubes like the lovely regulator tube VR150.

Yes. The glow lamp (that still comes in every power strip with a switch) is an extremely close relative, and the CCFL for backlighting is a relatively close relative too. But as far as I know, tubes filled with gas aren't usable in amplification circuits, at least not in linear amplifiers.

By the way, what tube was originally in the box that is in your profile pic?

 

[Ferrum Master]

what tube was originally in the box that is in your profile pic?

You cannot fill something with nothing. It is versa, you pump the matter out, politely ask that oxygen molecule to leave.

You can use VR150 in amps as zener diode as they discharge at constant voltage, so you can power 150V preamp tubes, that need less voltage than the outputs like ~800V for EL34. There are other gas discharge diodes, there is additional effect for those, due to their nature they act as natural sound compressor, as they are current limited, people used this property in the past for that purpose.

Mine there are 1986 year General Electric GE6080 alias 6AS7 or Soviet 6H13C, I bought like 60 pieces of those from exRadio location, so I base my designs around it, due to that I kinda lean on OTL designs, in terms of tube sound that is pretty boring, as they are pretty low THD design in the end, due to low gain, but low plate resistance and high current, perfect for high Z headphones.

I never have liked driving tubes from low voltage under spec, they sound mushy, you rob all the good they are known for. It is the opposite in my experience, some of them just open up at near highest voltage limits, maybe due to age, but then the even order harmonic distortion changes, as the distortion curvature is not linear and is voltage and operating point dependant. But as it more like artistic add-on here, you cannot complain or praise it, take it or leave it, either you like it or not. Based on psychoacoustic theory to whom we all apply you should not in long term listening sessions.

 

[Onasi]

Based choice of tubes, not gonna lie. Tube amps aren’t my jam anymore, prefer non-colored sound, but some of my acquaintances who love tubes insist that there’s nothing as good out there in terms of price to quality as older Soviet and nowadays Russian tubes.

 

[Ferrum Master]

Based choice of tubes, not gonna lie. Tube amps aren’t my jam anymore, prefer non-colored sound, but some of my acquaintances who love tubes insist that there’s nothing as good out there in terms of price to quality as older Soviet and nowadays Russian tubes.

They should check up their ears or look into measurement plots, they were and are more crap even when they came new. Any now exSoviet tech sought for foreign parts just because of the same reasons, I have had plenty of those you barely could match two out full bucket of those. It is like craving for Lada car, the bonnet will not open even if the car is brand new from the factory, but that's the thing, most Soviet men got their car and first thing they did is took the car apart and rebuilt it in order to drive it. Older people had much more technical and electronics knowledge on average, just they had to fix their stuff on daily basis and not that they were poor, there was deficit of any premium goods.

While now there is no other choice, either Soviets or China, they work, but those are different tubes in reality, different operating points, less meat, they are fine for guitar amps, as distortion is the main idea about those, but not all of them, I have some crazy post-stoner dudes with parallel 6L6 12 tube base amp still. For normal audio, like I said it is more artistic preference, so I am neutral about it. I use mine because of the even order distortion, due to our anatomy and how eardrum is built, I get way less fatigued listening to my OTL headphone amp versus a solid state one at work, so I am pretty pragmatic about it, I would not care otherwise.

Comparing my 6080 with 6H13C, the Soviet ones usually eat more heater current, like .5 to 1A more... That's utter pain, you need more powerful trans, it is not a drop in replacement. That applies for most tubes, their operation point differ, some do tube rolling and then conclude tube X sound better than tube Y, you cannot do that, most need to adjust operating points, the heck even older solid state amps needed quetescent current to be fine tuned with pots, there also thing with putting false labels on tubes now, you have remeasure each tube replacement jobs... Same weird stuff also for those opamp rollers, that's pretty bizarre stuff from my point of view. People doing reviews often do weird things, because they are too young to know and lack technical background. China makers are smart arses too, their designs are questionable for most parts and allow snake oilish stuff, because there is money in it.

Nothing beats 50ties era of RCA and Sylvania tubes due to material purity alone. The peak of tube technology.

 

[Onasi]

@Ferrum Master
I agree it’s more subjective than anything else. Trying to convince them otherwise is pointless since it’s just personal preference. Showing measurements is also not really worth it for that, hell, even aside from tubes we have examples. The Susvara measures like shit, yet plenty of people consider it the absolute pinnacle of headphones. Then again, if one is going for a tube amp I assume they already know that they are getting into purely subjective preference based territory - no tube amp will ever be as objectively “pure and flat” as a good solid state, that’s just a fact of life. I may prefer both the source and the transducer to be as neutral as possible, but some people love their incredibly janky setups and more power to them on that.

 

[VulkanBros]

Seems like a majority of portable DAC companies are Chinese based.

There are others, Chord, and especially their Mojo 2, which is British - I would prefer them, at any time, over all the Chinese stuff.....
After I switched to the Mojo 2, I am not looking other ways - Chord DAC's

 

[SOAREVERSOR]

Seems like a majority of portable DAC companies are Chinese based.

Not true at all. As mentioned Chord is out there, also ifi, audio quest, astel & kern, ear man, helm, questyle, woo audio, panther, I could go on.

Just like the IEM market though western products are more expensive and they don't flood the market.

There are others, Chord, and especially their Mojo 2, which is British - I would prefer them, at any time, over all the Chinese stuff.....
After I switched to the Mojo 2, I am not looking other ways - Chord DAC's

I had the first Mojo and loved it. Tried the Earman Angel and loved it. Now on the ifi Diablo-X which is overkill in the best possible way.

 

[AleXXX666]

LMFAO looking for picture I thought this greeny stuff is some circuit board