Juson Audio JTA35 Tube Amplifier, DAC & HP Amp Review

[SIY]

I would like to see the result as a (nearly) minimal phase step response without pre-ringing.

Why? A perfect brickwall at Nyquist will have so-called pre-ringing.

 

[beagleman]

What is bad?
Is a movie that was produced on classical celluloid bad and one that was produced digitally good?
Technically it's certainly worse, but film critics would say it has a different aesthetic

Edit:
In any case, the amp is not transparent! Whether the owner thinks that's bad sound, I think we'll have to leave it up to him.

Yes and no...........

Would you know the amp was not "Transparent", by only listening to it, and not knowing the mediocre measurements?

I think many are ((maybe rightfully so, I will admit in this case)) basing their ideal of a subjective experience solely on the measurements, which we all agree are mediocre.

I thought the "Acid test" was to listen first, determine any/all audible shortcomings, THEN by objective measurements see how they agree or disagree with the audible assessment.

 

[Antagron]

Yes and no...........

Would you know the amp was not "Transparent", by only listening to it, and not knowing the mediocre measurements?

I think many are ((maybe rightfully so, I will admit in this case)) basing their ideal of a subjective experience solely on the measurements, which we all agree are mediocre.

I thought the "Acid test" was to listen first, determine any/all audible shortcomings, THEN by objective measurements see how they agree or disagree with the audible assessment.

What I'm driving at is this: could this unit be worth buying and be enjoyable despite not measuring the best? It's a pretty cool little piece with lots of stuff that could be nice to have, especially for less than $200. It may not be the best objectively, but there have been, I'm sure, plenty of not objectively good, but still subjectively fine, devices in the history of electronics that are still plenty enjoyable. On this site, we measure DACs that are now pushing 130 SINAD when this is way beyond audibility, and I'm sure there is a threshold below that, even, where people couldn't really "tell" by ear, even if equipment can measure it.

 

[beagleman]

What I'm driving at is this: could this unit be worth buying and be enjoyable despite not measuring the best? It's a pretty cool little piece with lots of stuff that could be nice to have, especially for less than $200. It may not be the best objectively, but there have been, I'm sure, plenty of not objectively good, but still subjectively fine, devices in the history of electronics that are still plenty enjoyable. On this site, we measure DACs that are now pushing 130 SINAD when this is way beyond audibility, and I'm sure there is a threshold below that, even, where people couldn't really "tell" by ear, even if equipment can measure it.

I think we agree!

 

[TechLvr2]

IMO, like many of these small tube amps, at that price point it is a fun looking, cool desk toy for the office. Fidelity doesn't really matter for that.

 

[Bleib]

Cheap, but I wouldn't pay for poor performance no matter the design

 

[Beershaun]

But do we know it actually sounds bad? Measure bad and sound bad are not necessarily the same thing.

Sure. Does it give them the "tube" sound so they can hear what it sounds like to have a tube amp and decide for themselves? Also measuring bad and sounding good are much more rarely the same thing.

 

[BostonJack]

Thanks for the test Amir. It was fun to see how such a small cheap tube amp performs.



I absolutely agree with you about Juson Audio JTA35 poor frequency response. That was a bit sad BUT beyond that for all the features there are and a pair of tubes that shine at a price of US $180. It's ok, I think.


And Juson Audio JTA35 costs $180. It actually doesn't perform too badly anyway, considering the price and the fact that it's a tube amp.

This was appropriate. The company has posted a video on YouTube. If you want to see more of what it looks like:

I would put this on my desk at work and take Zoom calls through it and earn some sort of strange rep with my co-workers and consider it money well spent.
[that is just the way i roll]

 

[BostonJack]

This is what I said to myself in peto: here is a manufacturer who uses the word digital amp like one takes out garlic cloves to ward off vampires.

garlic cloves totally work. I'm working with a crew from Romania and they know this sh*t cold.

 

[BostonJack]

Interesting...this company sent their product to ASR knowing what they do at ASR. Knowing the outcome. I can only assume they have no test equipment for their own product as the results can only be what they are. What did they think the upside would be? At $180 did they think that any publicity is good publicity? I actually think it's better than that Carver tube amp which is much more more expensive, I guess maybe that's it's forte. So in short it's crappy but not as crappy as something that's really crappy.

And also I don't understand tubes, let's say you could build an amp out of rocks and roofing tar, it would work but it would have very low output and terrible distortion. Would you praise it because it sounded sweet and was old school or exotic? I can appreciate a Model T and it's position in history, however I don't want to drive one. Results may vary.

Lastly it was nice of Amirm to give them the opportunity to not publish, good form.

I would totally love driving a Model T, or a Model A for that matter. Would make a blood sacrifice to drive a Stanley Steamer and made a moderately sincere effort to import a Treblant as a homage to the Cold War. I wouldn't commute to work on any of these, but commuting to work is bullsh*t anyway.

 

[DanielT]

I would totally love driving a Model T, or a Model A for that matter. Would make a blood sacrifice to drive a Stanley Steamer and made a moderately sincere effort to import a Treblant as a homage to the Cold War. I wouldn't commute to work on any of these, but commuting to work is bullsh*t anyway.

Go on vacation and experience such a car by participating in:

Trabi-Safari

www.trabi-safari.de

 

[oscar_dziki]

I'm kind of impressed with this product. You get the performance you should expect from tubes, super tubey presentation, remote, Vu meter, nice lamp cage, headphone out, and loudness applied by default I could imagine installing this amp myself in one of my rooms and maybe getting a turntable for it.

 

[MacCali]

I'm kind of impressed with this product. You get the performance you should expect from tubes, super tubey presentation, remote, Vu meter, nice lamp cage, headphone out, and loudness applied by default I could imagine installing this amp myself in one of my rooms and maybe getting a turntable for it.

Might not be super tube’y as a hybrid. I have both a TA-10R and Liquid Platinum HPA and both do add some flavor but I doubt it’s anywhere near pure tube amps

 

[MacCali]

Hats off to the company. If you’re deeply entrenched in the audio world this is a drop in the bucket for the price. If you aren’t than you probably won’t even notice the flaws. So seems to be a win win situation.

I know there’s potential for a 150 dollar dac amp performs better than this.

Without a doubt that’s accurate. Simply put it’s just a toy to have fun with. This will give the company room to improve without buying a 30,000 dollar AP and make those funds into development

 

[beagleman]

I would totally love driving a Model T, or a Model A for that matter. Would make a blood sacrifice to drive a Stanley Steamer and made a moderately sincere effort to import a Trebant as a homage to the Cold War. I wouldn't commute to work on any of these, but commuting to work is bullsh*t anyway.

Trust me, you were NOT missing much about the Trebant!

A good friend owned one when I lived in Germany and it was VERY mediocre to drive. Hard to even explain what was bad, as is was nothing like ANY car I had driven before or since.
Noisy, slow, poor handling, rubbery feeling steering and suspension, I mean it was just quite bad overall.

 

[pseudoid]

Thank you @amirm, you are a persistently patient person. After the results of the first THD measurement, I would have gone fishing or for root-canal!

I am still waiting and hoping for the ASR lottery/raffle/auction to give-away some of these (manufacturers') gear, upon completion of your testing/review.
I would not be bidding on this item though!

 

[mhardy6647]

VERY mediocre

I love expressions like this!
(lest anyone would think that I am very ambivalent about them)

After all, one of the tenets I live by was and still is: strive for mediocrity.

 

[pseudoid]

After all, one of the tenets I live by was and still is: strive for mediocrity.

You are a copycat!
The new fundamentals [tenets?] of higher-education now is to welcome mediocrity with open arms.
I stopped wearing deodorant; so that I can keep these folks away.

 

[mhardy6647]

Hey, now -- you've gotta remember: mediocrity's a stretch for some of us!

 

[hyfynut]

This is a review and detailed measurements of the Juson Audio JTA35 stereo hybrid tube amplifier including DAC, Bluetooth, Phono input and headphone out. It was sent to me by the company and costs US $180.
View attachment 339818
As if all that functionality was not enough, we even have a pretty VU meter! And oh, motorized volume control remote control too!
View attachment 339819
There is even subwoofer out!

Overall build feels good and polished. Speaker terminals are oversized for class (good) and we even have built-in power supply. Let's see how it measures.

Juson Audio JTA35 Measurements
Let's start with the power amplifier:
View attachment 339820
Don't expect super clean performance from a tube amp especially at this price and that is what we get. Noise is high and shows up in our SNR tests:
View attachment 339821

Distortion is fortunately frequency independent:
View attachment 339822

Crosstalk is poor:
View attachment 339823

Frequency response has peaking at the low and upper end:
View attachment 339825

Impedance is low though as we see from difference between 4 and 8 ohm. There is a sharp cut off which existed even when I switched to digital input:
View attachment 339824

Here are the power sweeps:
View attachment 339826

If we allow more distortion, power increases with good bit of heardroom:
View attachment 339827

Interestingly we get almost the same amount of power into 8 ohm (we are current limited):
View attachment 339828

Same voltage advantage exists when testing headphone out with more power delivered at 300 ohm:
View attachment 339829

View attachment 339830

Finally, I tested the RIAA equalization using phono input:
View attachment 339831

Kind of strange response with channel mismatch.

Conclusions
It is hard to imagine so much functionality being in such a reasonably priced but quality (physical) implementation. It even went after the soft spot in my heart with that VU meter. The other part of my heart was not pleased with measurements that are lackluster across nearly entire suite. Company support has been fantastic though and when I gave them the option to ditch the review they chose to have it be published anyway! Not enough companies send me products and fewer still don't mind results like this. For this, they need to be praised. Hopefully future products will have better objective performance.

Not having any use for tube products, I can't recommend the Juson Audio JTA35. If you are situated otherwise and looking for a very low cost of entry and high functionality, you may dig what JTA35 has to offer.

Manufacturer Specifications are provided in post #9 below.

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As always, questions, comments, recommendations, etc. are welcome.

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Would like to see it on the list to compare to the other amps you've tested.