Juson Audio JTA35 Tube Amplifier, DAC & HP Amp Review

[LTig]

What I understand from this is that when not expansive but popular products like Wiim amp measurements are not being published is because they came out poorly and you gave them the option of not publishing it? Did you gave this option to PS audio as well? I must say that this is disappointing.

I cannot remember that PS Audio ever sent something to @amirm to be reviewed.

 

[LTig]

No, it hurts me the most as I have to go through the full set of measurements and not be able to publish anything. Usually this means an entire evening for electronics and multiples of that for speakers.

Ever thought about sending an invoice?

It benefits you in the long haul as the companies go and redesign these products and come back with better performance. They do that because I allow them a second chance. This just happened as a matter of fact.

You could think about publishing the review if the company does not react with an improved product within one year or continues to sell the one you've reviewed unchanged.

 

[AudioSceptic]

Y'all drink pricier beer than do I -- or perhaps just a lot more of it.

That's what I thought. I hope DSJR is talking per month, not per week!!

 

[amirm]

What I understand from this is that when not expansive but popular products like Wiim amp measurements are not being published is because they came out poorly and you gave them the option of not publishing it?

Don't go making conspiracy theories. WiiM told me they were going to send an amp just a couple of weeks ago. It may have just arrived here so have not tested it. I suspect the reason they didn't send me the amp was that I took 3 to 4 months to review their new DAC!

 

[amirm]

Ever thought about sending an invoice?

It is probably the right thing to do but I don't want to come across as demanding payment to test gear. FYI a couple of times companies have donated money to make up for the time I put in the testing.

 

[AudioSceptic]

We actually do drink that on occasion.

Naah. Single Malt Whisky.

 

[xaviescacs]

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.

Kudos to both. Great and honest job.

 

[SIY]

Output stage is something like an LM1875. No tubes. And if the input stage were designed better, there would be one to two orders of magnitude less distortion. An amp with tubes, not a tube amp.

And as someone who loves designing and building tube gear, it always pains me to see the entire genre tarred by something like this which isn't even a tube amp.

BTW, many of the amps with "output transformers" have no such thing- it's a metal box with other circuitry (or heat sinks) in it.

 

[DrCWO]

Personally I won't use this amp as I'm committed to transparency

Despite of that I think it is a very nice offering (180$!) for someone who likes tubes and wants to have an integrated amp for a small room. Also it looks good and somehow different compared to other audio gear. Stream to it compressed audio from Spotify and you even won't notice that it cuts off at 20kHz.

Sure, technically far beyond perfect but still listenable. I guess it will find a lot of tube loving customers

 

[AudioSceptic]

Personally I won't use this amp as I'm committed to transparency

Despite of that I think it is a very nice offering (180$!) for someone who likes tubes and wants to have an integrated amp for a small room. Also it looks good and somehow different compared to other audio gear. Stream to it compressed audio from Spotify and you even won't notice that it cuts off at 20kHz.

Sure, technically far beyond perfect but still listenable. I guess it will find a lot of tube loving customers

Would anyone notice the 20 kHz cut-off with *any* source?

 

[DrCWO]

Would anyone notice the 20 kHz cut-off with *any* source?

No idea what filters they use but steep linear phase filters produce a lot of preringing. In general preringing may be audible. I don‘t believe it is at 20kHz but never tested, probably a more an academic question. To be sure I run my gear with 96kHz so preringing is definitely out of audible band

 

[Beershaun]

Gosh. I am not sure how to rate this. It's a poor performer but so cheap and pretty. Maybe it's a good way for people to dip their toe into tube amps at an affordable price so they can learn it sounds terrible and runaway without blowing their budget?

 

[Antagron]

Gosh. I am not sure how to rate this. It's a poor performer but so cheap and pretty. Maybe it's a good way for people to dip their toe into tube amps at an affordable price so they can learn it sounds terrible and runaway without blowing their budget?

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

 

[DrCWO]

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

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.

 

[JDS]

Kind of a bargain. Big-name tube amps make you shell out thousands more for performance this bad.

 

[SIY]

In general preringing may be audible.

If memory serves, all attempts to show audibility have given no positive result.

 

[mhardy6647]

What is bad?

indeed.

 

[DrCWO]

If memory serves, all attempts to show audibility have given no positive result.

https://vbn.aau.dk/ws/portalfiles/portal/227876517/2007_M_ller_et_al_AES_Journal.pdf

 

[SIY]

https://vbn.aau.dk/ws/portalfiles/portal/227876517/2007_M_ller_et_al_AES_Journal.pdf

Thanks for putting the link in here. I'm reasonably familiar with this paper (I did some DBTs of my own to see what I could hear from all-pass filtering, albeit at higher than second order). It looks at causal all-pass audibility, not so-called pre-ringing, especially not pre-ringing from anti-imaging filters.

 

[DrCWO]

Thanks for putting the link in here. I'm reasonably familiar with this paper (I did some DBTs of my own to see what I could hear from all-pass filtering, albeit at higher than second order). It looks at causal all-pass audibility, not so-called pre-ringing, especially not pre-ringing from anti-imaging filters.

As I already wrote this is more an "academic" issue than an audible
I may be a bit sensitive about this because I often calculate DRCs for customers and I would like to see the result as a (nearly) minimal phase step response without pre-ringing.