Review and Measurements of xDuoo TA-10 Tube DAC & HP Amp

[amirm]

Is the tube in the output stage or it is just a buffer?

From what I have read, it is a buffer with transistor output.

 

[gvl]

From what I have read, it is a buffer with transistor output.

The level of distortions is pretty dramatic for a simple buffer.

 

[amirm]

The level of distortions is pretty dramatic for a simple buffer.

I am with you on that. If I have time, I will open it and take a look....

 

[Xulonn]

What brand of 12AU7 is in the amp? Do you have to send the amp back soon?

Perhaps an ASR member who is into tubes could send you a couple of highly-rated 12AU7/ECC82 tubes to see if there is any difference in distortion. When I see all of the subjectivist rantings about various variations of this preamp tube, with some highly-prized brands selling for up to $300 each, my B.S. meter flashes red.

On the cheaper front, the Shuguang 12AU7 seems to be well regarded, selling for less than $10 each + shipping on eBay. Another popular brand is the Tung-Sol Russian reissue 12AU7 for about $25 with shipping at Amazon.

I think this might be an opportunity to easily see if there are measurable differences by switching to a different, audiophile-approved tube.

 

[amirm]

What brand of 12AU7 is in the amp?

It just says "12AU7 CHINA."

 

[amirm]

Perhaps an ASR member who is into tubes could send you a couple of highly-rated 12AU7/ECC82 tubes to see if there is any difference in distortion.

Based on testing I have done in the past, I am quite dubious that there is much measureable distortion difference between them. But sure, if someone wants to send them, I can test.

 

[ZolaIII]

Try it with German RFT Ecc82.
Hire you go:
https://www.thetubestore.com/rft-ecc82-12au7
They are rare & make wonders so that's actually a very good price as they go for twice that much.
They are balanced and with very little distortion.
I really like this DAC & AMP combo especially for the price. So please put a normal tube in it & do the testing again.

 

[solderdude]

The level of distortions is pretty dramatic for a simple buffer.

It looks like the tube is in the gain stage (given the output voltage swing) followed by a SS buffer output stage.
Think it is a good thing the tube is not in the DAC section which I think performs pretty well.

 

[beefkabob]

The DAC voltage out is below 2V RMS. Can you turn up the volume to get it to 2V or is that with volume all the way up?
For DACs with volume controls, is it possible to do a 1V RMS test and see how that affects distortion? I know that for Benchmark DACs, the resistors add distortion. That's why they recommend their pre-amps, which use a very quiet volume section to reduce the distortion.

 

[invaderzim]

I have no pressing need for this in any way, but have an itch to buy one

This is me after pretty much every review. It is also what makes it so some youtube reviewers can make a living off of raving about products.

 

[Dogen]

Nice review Amir! xDuoo seems to have a very interesting line of products, and obviously have taken some care in their design and performance. I hope they’ll send you more gear to review.

I like having tube amps as an option, for no rational reason other than an appreciation for their history and aesthetics. For a designer to honor that heritage with an attractive, decently measuring amp is very encouraging.

 

[filo97s]

It looks like the tube is in the gain stage (given the output voltage swing) followed by a SS buffer output stage.
Think it is a good thing the tube is not in the DAC section which I think performs pretty well.

yup I think so too.
Such a power under low impedance loads is quite rare for a full tube amp. The tube must be only a buffer for volume regulation, and it's out of the line out section because the RCA on the back has fixed volume.

 

[mshenay]

Oh nice, I'm surprised to see this as well! Price on this unit is pretty aggressive too. I'd certainly like to see future tube stuff measured again'st this too

 

[Veri]

Oh nice, I'm surprised to see this as well! Price on this unit is pretty aggressive too. I'd certainly like to see future tube stuff measured again'st this too

Like the TA-20 balanced version

 

[mshenay]

Like the TA-20 balanced version

Oh nice! Didn't know that had that, know I'm extra curious!

 

[Veri]

Oh nice! Didn't know that had that, know I'm extra curious!

Yeah this one has an XLR output for 'convenience' with the SE output in fact going to it, the other TA-20 one has two tubes for true differential output.

 

[mshenay]

Yeah this one has an XLR output for 'convenience' with the SE output in fact going to it, the other TA-20 one has two tubes for true differential output.

Well I like the XLR for convenience, that's a trend I'm rather happy caught on and yea I imagine the TA 20 is running more of like a dual Mono configuration with a pair of dual triode tubes as I believe that's what 12au7's are. I'd also venture to say the TA-20 runs as a hybrid given it includes a

• Class-A transistor expansion

Which is nice, hybrid designs tend to do very well both measured and subjectively and I'm sure some digging would in fact confirm the same for the TA-10 as I doubt they'd run the cheaper unit without some solid state circuitry

 

[ObjectiveSubjectivist]

Hmm i see high impedance on headhone output. I guess it will probably be poor match to low impedance headphones. I want to pair of with audeze lcd xc. They are 20 ohms. Any thoughts ?

 

[ZolaIII]

Hmm i see high impedance on headhone output. I guess it will probably be poor match to low impedance headphones. I want to pair of with audeze lcd xc. They are 20 ohms. Any thoughts ?

Let's just say 64 Ohm's should be considered as minimum you would like to drive with this, eventually try with 48 Ohm's condensator electro static hungry one's but I don't think even that would be satisfactory. For a matter a fact it's with any even remotely serious solution with tubes & twice that much with balanced one's. You can play with those headphones & add a tube feal to it through vts software (on Windows) my favourite toy of such is PTEq-X (passive EQ+ tube emulator), it's free. Those earphones are very efficient and don't need a very strong amp but they really need a very good DAC & balanced out. So forget about pairing those with tube amp & instead use software emulated one if you really insist on adding a touch of how it sounds.
Best regards.

 

[Jimster480]

Looks interesting for a tube product!