My personal review of Aune T1 MK2 Headphone Amplifier (image heavy)

[creatip123]

 

The first thing that caught my eyes on the Aune T1 MK2 was the unique design, specifically the vacuum tube it's using. There are a lot of other headphone devices that use vacuum tubes, namely the renown Bravo Ocean, which also caught my eyes I might add, but most of other vacuum tube devices are amplifier only (tube amplifier). The Aune T1 MK2 differs in that it's a tube DAC. So the vacuum tube corresponds to the DAC circuitry, not the amplifier circuitry. The amplifier itself is a solid state amplifier. So in a way, the T1 is a hybrid device, combining analog vacuum tube in its DAC, and digital solid state in its amplifier. 

 

Now there are other tube DACs in the market, ranging from higher-end ones like Accustic Arts Tube DAC II to lower-end ones like XuanZu U2012. After some researches and reading reviews, the Aune T1 MK2 takes the cake, in term of performance vs price. Lots of good words about the T1, while the price is reasonable (to my pocket, most importantly ).

 

So anyway, ordered one, and it arrived a few days ago. The price in amazon is $219.

 

 

The package contains the main unit, a vacuum tube that comes with it (mine was the Electroharmonix 6922EH), manual book, USB A to USB B cable, 2 sets of acrylic tube cage, 3,5mm to 1/4" adapter (not shown in the picture), and the power supply (mine was AC 220V to AC 15V 1A)

 

My first impression when I open the packaging was, this thing is heavy! The whole box and stuffs weighs around 2kg (estimation). When I open the box and took out the stuffs inside, turned out that the heaviest thing inside was the power supply, weighing more than 1kg (estimation). The amp itself weighs less than 1kg, but I'm guessing it's more than half a kg. It weighs a bit more than my HE-400 headphone, which is around 400g. 

 

I must say, I'm impressed starting from the box itself. The box looks very elegant, with the marking 'T1 MK2' embossed in silver on top of it (you can see it in the picture above). 'MK2' means it's a second/newer generation of T1. The main difference of the two versions is the MK2 is an asynchronous USB DAC, meaning it got its own clock inside, while the original MK1 version doesn't have a clock inside, hence the MK1 is synchronous. You can read more about it here: http://en.wikipedia.org/wiki/Asynchronous_communication

 

 

All the data contact jacks on the unit are all gold plated, The front headphone jack, the RCA in-out jacks in the back, and the USB jack are all gold plated. Even the included USB cable's plugs and the vacuum tube legs connectors are gold plated as well. This makes the T1 much more elegant and good-looking. The only connector that's not gold plated is the AC plug and jack in the back.

 

The casing is all brushed aluminium. There are 2 colors to choose, the black like mine in the picture above, and the white/silver. The aluminium plate it's using is quite thick. You can tell immediately by knocking on it with your fingernail. It feels solid and nice.

 

 

 

I was using a Fiio E10, before this T1, so my first impression regarding its size was, it's kinda big and bulky. You can see the size comparisons in the pictures above, compared to the E10 and a standard sized Zippo. It's about 8-9 times bigger (in volume) than the E10, not counting the protruding tube. It still sits nicely on top of my CPU though, so it's all good

 

 

The back panel. It got the power in jack, USB B jack, audio in and out RCA jacks, and an on-off switch.

 

It's a tube DAC + headphone amp combo, but you can use it in many ways, such as:

- Use it as a tube DAC + headphone amp, just plug your headphone to the front audio jack, and plug the USB cable to your PC or other compatible devices.
- Use it for its tube DAC only, by plugging RCA audio cables from the T1's audio out jacks to another amp. You can use a speaker amp to power speakers, or maybe a better headphone amp.

- Use it for its headphone amp only, by plugging RCA audio cables from your audio source to the T1's audio in jacks. This way, the tube DAC is bypassed, and you're using the T1 strictly as a solid state headphone amp.

 

This versatility is also another strong feature of the T1 that drew my attention.The last option is not very favorable though, because the strong feature of the T1 is its tube DAC. 

 

 

In the top panel, it got a big metal volume knob (which also a plus for aesthetic), the vacuum tube connector, and a line-usb switch. Switch it to USB (like in the picture) to use it as a tube DAC (with signal feeding from the USB cable in the back), or switch it to line to use its amplifier only. 

 

 

In the bottom panel, it got the 4 screws covered in already-installed rubber feets. There is also a pair of gain switch. Each switch for each channel (left and right), so you can change the gain separately for each channels. 

 

 

The switches' setting diagram. I found the T1's gain circuit a bit 'dirty' though, that I avoid setting it to full 16dB, and kept it at 10dB (0dB is too quiet for my HE-400).

 

This is the specs of the T1 MK2, taken from their website:

 

Product : T1 24BIT TUBE USB DAC
Color : silver , black
Weight : 2KG
Size : 15.5*9.7*4cm
Frequency response : 20hz-20khz
Signal to noise Ratio : >=120db 
Lint out : 2Vrms
Suitable headphone Impedance : 30ohm~600ohm
Headphone Amp output : (biggest is 20V) 32ohm--1000MW ,120ohm--400MW ,300ohm--150MW
Line out insider impedance : 100ohm
Headphone amp insider impedance :10ohm
USB support : 24bit/96kHz
Input jack : analog RCA jack*1 , USB jack *1
Output jack : analog RCA jack *1 , 6.5mm jack *1 Unpack : T1 24bit tube USB DAC ,power adapter(220/110V) ，PC USB cable , 6.5mm to 3.5mm stereo F adapter , User manual.

 

With the SNR rating at more than 120dB, it's very 'black' (which is nice ). It packs quite a punch, compared to my old Fiio E10. The T1 can output max 1000mW (1W) @32 ohms, while the E10 is 100mW @32 ohms. It certainly benefits my HE-400, which is a planar headphone. 

 

Now, from unboxing, you gotta do some assemblies first, the standard cabling, and mainly installing the tube. It's pretty straightforward, just plug the tube into the connectors, but I found that because it's still new, the connectors are still very tight. You gotta push and at the same time wiggle it slowly left and right. If you use sheer force, there's a big chance you'll snap the legs, or  break the tube's glass. 

 

There is 1 thing that you gotta be careful when installing, which I found out first hand. That is, when you're installing the acrylic tube cage. Good thing they include 2 sets of the cage, because I broke the first set. First, you gotta peel of the plastic coverings of the acrylic cages, otherwise it'd be to thick to install.

 

 

Now, you can see there's some kind of hook in each of the acrylic cage's legs. This will become a problem. You can install it, but you can't take it off, not without breaking the legs. I broke the legs on the first set, and it fell right inside the unit. I had to open the bottom plate, to take the shards out. It might be dangerous to leave the acrylic shards inside the unit, because acrylics are prone to melt by heat, as any other kind of plastics.

 

 

What you gotta do is take a razor blade, or an Xacto knife, and cut the hooks off of the legs. It won't be as sturdy as the original ones when installed, but you won't risk the legs snapping when you take the cage off to change the tube (and believe me, you will want to shop for new tubes to play around )

 

 

The T1 utilizes a pre-amp vacuum tube in its DAC circuit. My guess, after the digital signal is converted into analog signal, it's then processed by the pre-amp tube, before it's let through to T1's amp, or an external amp. This is, in my opinion, the strongest feature, and the main reason people buy the T1. By changing the tube to other compatible types, you can actually change the sounds it produces!! Be careful though, you gotta use a compatible tube. Same legs formation (9 pins) doesn't mean it will automatically be compatible.

 

The types of vacuum tube the T1 uses are 6N11 and 6922. So when you shop online or offline, just look/ask for tubes that are compatible with those 2 types. Some compatible ones are:

 

 

6DJ8, ECC88, 6922, E88CC, 7308, 6N23P, 6N27P, 6N11, 6N1P, 7DJ8, PCC88, ECC189, 6ES8, E188CC, ECC86, 6GM8, PCC189, 7ES8, Cca, CV2492, CV10320, CV5231, CV5354, CV5358, M3624

Source: http://www.head-fi.org/t/633006/aune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq

 

 

 

Another thing to note is, when you turn it on, you gotta wait for about 30 seconds for the tube to warm up. This is just the way it goes for vacuum tubes. When you switch it on, you can see some amber glowing stuffs inside the tube.

 

 

When it's ready to go, a white LED in the unit will light up, like in the picture above. You won't get any sounds before the white LED lights up.

 

The T1 is a USB audio device class 1.0, which means it's supported natively by PC operating systems (windows, mac os, linux, etc). In other words, just plug and play, it will be detected and start running automatically, without needing any kind of specific drivers. This further adds the versatility and mobility of the T1. It also can be used on ipad (tested with my ipad 3), with the Camera Connection Kit adapter, so I'm guessing it will also work with other idevices (iphones need IOS 7 to support extracting digital audio data from the iphone, though), and androids that support OTG.

 

When used, the unit becomes a bit hot. Not dangerously hot, or too hot to touch, but a bit hotter than any other amps I've used. Perhaps it's the effect of the tube (the tube becomes hot by use too). I've never used any vacuum tube devices before, so I'm guessing it should be normal for it to become a bit hot. I might get a small fan in the future though, just to improve the air flow.

 

That about covers the technical aspects. Now what do I think about the sound of the T1 MK2 itself?

 

Before I use the T1, I was using a Fiio E10 (olympus), so I'll compare it mainly to the E10. The bigger power output of the T1 really benefits the HE-400 compared to the E10. Like other planars, the HE-400 sounds better with more current, which I think is what the E10 lack of. Bigger current for my HE-400 means punchier and tighter kicks and basses, also wider overall sounds. Before I got the T1, I had to use my E10 in combo with my Lepai amp to get that kind of sounds. Turns out the T1's amp is adequate to replace the E10 + Lepai combo. At 10dB gain, I set the T1's volume knob to about 80-85%, with Foobar's volume at 50%. If I wanna rock it, I can set the knob to 100% without any distorted sounds.

 

 

First impression when I plug it on, with the supplied 6922EH tube, damn the sound is WARM!! In my personal opinion, and the reviews I've read, the E10 is already considered warm, but the T1 is warmer and got richer sound. It doesn't go as much as turning my HE-400 into a dark headphone, as it still retains the highs nicely, but tilted quite heavily towards lower mids. The wideness is about the same as the E10, while with the E10, I could distinguish a bit more details. Now I happen to love warm and rich sounds, so I absolutely love the HE-400 + T1 combo. For those of you who prefer brighter sounds, I wouldn't recommend the T1. Most probably you could get other DAC+amp combo that's brighter with the same price.

 

Soooo....aside from the bigger power, the T1 is on par with the E10? Well, yes and no. I'd say it's on par with the E10, when plugged with the supplied 6922EH tube. Now I bought the T1 bundled with an additional tube, which is the Genalex Gold Lion E88CC (gold legs), installed in the picture below.

 

 

When I swap the 6922EH with the Gold Lion, oh man, the sounds became oh-so-much-nicer. Compared to the 6922EH, the Gold Lion tube produces warmer, more detailed, and much wider sounds. With the Gold Lion installed, the T1 now stomps the E10, in my opinion. I even tried it with my AD700, and truly it does make the AD700 sounds much better. With the HE-400, I'm loving every seconds of the sounds it produce! It's warm, detailed, rich, intimate, and wide at the same time. String intruments like piano, guitar, cello, violin, and the likes sound exceptionally good. The Gold Lion tube adds more sibilance compared to the 6922EH though, but not so much that it becomes annoying.

 

Because I like warm and rich sounds, with the E10 + HE-400, I fiddled with my EQ on Foobar, to get the sounds I want. With the T1, that EQ settings become too much. With the T1 now, I kept the EQ on flat settings, and I already got the sounds I want. So you can say the E10 is flatter and more transparent than the T1.

 

Now I'm curious of what other various tubes would do to the sound. I'll see if I can get my hands on other replacement tubes, and I'll update this topic when I do. 

 

In conclusion, if your preference is similar to me, warm, rich, intimate and wide sound, the T1 is the thing for you. Paired with my already warm HE-400, they do a fine job of producing my sound preference. The replaceable pre-amp tube is a very nice feature. You can change and tune the sounds it produce just by replacing the tube, and it's completely reversible. It does color the sounds quite a lot (to my liking, though), so if you prefer more genuine, transparent sounds, maybe the T1 is not for you.

 

 

The perfect combo for me, as of yet...

[Lays]

Would like to try this on my LCD-2 for shits and giggles, I want to try it with lots of things, but don't have the money to spend on buying a zillion things.

 

I asked a store near me if I could bring my LCD-2's with me and try out amps, but they said it's not a retail store, only a wearhouse + private showing place.

I'd make an appointment to go, but even if I found something I liked I don't have a few hundred dollars to drop on it.

 

Need to get myself to a head-fi meet sometime.

[creatip123]

Would like to try this on my LCD-2 for shits and giggles, I want to try it with lots of things, but don't have the money to spend on buying a zillion things.

 

I asked a store near me if I could bring my LCD-2's with me and try out amps, but they said it's not a retail store, only a wearhouse + private showing place.

I'd make an appointment to go, but even if I found something I liked I don't have a few hundred dollars to drop on it.

 

Need to get myself to a head-fi meet sometime.

 

Dat store I wrote about, I can bring and test anything and everything there. Mostly headphones and IEMs though, not so many headphone amps.

 

When short on cash, don't do anything. That's what I did, just stop doing anything new. I stopped reading reviews, stopped going to audio stores, even stopped window shopping. I just pretend my headphone and dac/amp are the last of its kind in the world....

[creatip123]

Would like to try this on my LCD-2 for shits and giggles, I want to try it with lots of things, but don't have the money to spend on buying a zillion things.

 

I asked a store near me if I could bring my LCD-2's with me and try out amps, but they said it's not a retail store, only a wearhouse + private showing place.

I'd make an appointment to go, but even if I found something I liked I don't have a few hundred dollars to drop on it.

 

Need to get myself to a head-fi meet sometime.

 

Forgot to say, the song you posted about, the 'Hero - Pegboard Nerds'? The song sounds incredibly wide with the T1 + Genalex tube. I didn't remember the song to be this wide on Fiio E10. Nice....very nice...

[remi2207]

look like nice.

[Durendall]

Literally made an account for this haha, but if anyone is looking to pick up this DAC/AMP combo, it is dropping on MassDrop right now!  The final price being $169.99, this also includes the gold lion tube!!  Thanks for the review, let me commit to the drop and feel super excited!

[Douglas Wicker]

Could someone please tell me whether this can be used to pass through rca signal without heating the tube? I intend to use it as a DAC/ headphone amp as well as a headphone amp for my record player via the RCA in and a pass through for both pc and turntable to my amp and speakers via the RCA out. COuld someone explain whether this is possible?

[SSL]

On 2/4/2016 at 1:38 AM, Douglas Wicker said:

Could someone please tell me whether this can be used to pass through rca signal without heating the tube? I intend to use it as a DAC/ headphone amp as well as a headphone amp for my record player via the RCA in and a pass through for both pc and turntable to my amp and speakers via the RCA out. COuld someone explain whether this is possible?

 

To the best of my knowledge, the tube is part of the DAC section. Using the line-in will utilise the amp portion only, thus bypassing the tube. However, I believe that the tube will still be powered at all times that the unit as long as it is turned on, which it must be to use the amp.