Review and Measurements of Hifime UDA38Pro DAC

[oliveoilthansnakeoil]

they did their own testing (using RMAA?) and while they get about 10 dB or so better performance than I got, it is nowhere near the advertised potential for the DAC chip.

It means they can test their products. I don't understand. So why didn't they test the product before release it?

 

[maverickronin]

It means they can test their products. I don't understand. So why didn't they test the product before release it?

I'd guess either a bad batch or something got messed up between prototyping and production.

 

[gvl]

It means they can test their products. I don't understand. So why didn't they test the product before release it?

They just write fake reviews instead, a proven method to boost sales as opposed to dry numbers that most people do not understand.

 

[Deleted member 3116]

@xevman
Figured this post is more appropiate here
not surprising they arent hot.... thats disappointing.
I own the UDA38 Pro and although I enjoy the way it sounds its clear that it struggles in some ways, the recent measurements confirmed it.
I became less reluctant to modding it after seeing the measurements (SMD was intimidating, 1 mistake could cost you).

It uses 2 OPA2134 op amps before the OPA1622 which always seemed like its biggest flaw, the OPA2134 doesnt seem too bad on paper and it does sound nice but when comparing it in an O2 headphone amp with the OPA1612 (which the D50 uses) it's obvious the 1612 is on a different level, in fact it is the most transparent op amp available right now I believe. The 1622 packs some serious power and is little less dry sounding at the cost of being slightly less accurate than it's predecessor , the 1612.

I replaced the 2134 with 1612 in UDA, there was no DC offset and there was sound which was a great start.
After some listening the differences were noticeable, the speed and seperation of the music had improved , particulary in the bass, soundstage is bigger and more realistic. vocals and instruments sound more distant which is less 'fun' but again seems to be result of these op amps ability to better convey a sense of space in the music.

Unfortunately both the 1612 chips are getting quite hot even with nothing playing which indicates instability, there isnt much that can be done to fix this.

However I just discovered after plugging in some sensitive IEMs that one of the OPA1612 seems to be faulty, with a very low, constant hissing.
Although both chips are getting hot I have experienced one faulty chip can effect another in a seperate channel, so there is still some hope.
If after replacing the faulty chip they are still getting hot the next replacement to try will be an LM49720/LM4562. not far off the 1612 in performance and not as sensitive to the application.

 

[Veri]

No one here will take you serious with simple claims of drastic difference in sound between op-amps. This isn't "that kind" of forum.

 

[Deleted member 3116]

No one here will take you serious with simple claims of drastic difference in sound between op-amps. This isn't "that kind" of forum.

the difference is not ''drastic'', it is the difference you would expect going from 1 very low distortion op amp to a better one. Sorry if it seemed exaggerated, it was directed towards people who are familiar with the differences in sound between op amps and can understand the small scale of these differences. I did not mention a change in tone or detail because there is none, it ''sounds'' the same.
The differences are subtle, like the difference between Sabre 9018 and 9038 DACs, but that definitely doesnt mean they arent important.

Differences.

of course I only shared this to explain myself after asking for some help, you are right that this advice will not benefit anyone here but it is a public forum free to be viewed by anyone.
feel free to ignore this

 

[gvl]

Sober up and face the facts, this DAC is a POS, no op-amp can change that.

 

[Zilfallion]

No one here will take you serious with simple claims of drastic difference in sound between op-amps. This isn't "that kind" of forum.

Not saying it will be that drastic of a difference, but we did have this whole thread a couple months ago on the topic. Do Audio Op-Amps sound different. Though the results of that are mildly questionable, as the thread gets into discussing the study's setup.

 

[έχω δίκιο]

the difference is not ''drastic'', it is the difference you would expect going from 1 very low distortion op amp to a better one.

Perhaps it's confirmation bias. All humans are susceptible to it.

 

[andreasmaaan]

There’s no doubt that opamps can sound different, although of course not all. The idea that this DAC’s deficiencies are explained by its opamps is extremely unlikely though.

 

[Deleted member 3116]

Sober up and face the facts, this DAC is a POS, no op-amp can change that.

you dont own this DAC and have zero experience with op amps , how does anything you say on this subject hold any value? could you try leaving the discussion to amirm or at least be a bit more civilised in how you respond.

Also it wasnt clear in the ''final follow up'' were the measurements from Hifime with the same unit or a different unit?
if its the same then all the original measurement are potentially inaccurate, if its different then the

Finally, the main point was to help someone who already owns this DAC, its pretty much impossible to sell it now since so many people , particularly beginners, take measurements as gospel, so finding ways to improve it makes sense. above all else it was a fun process...

 

[έχω δίκιο]

you ... have zero experience with op amps

I didn't see him say anything to that effect.

Finally, the main point was to help someone who already owns this DAC, its pretty much impossible to sell it now so improving it for few a extra dollars makes sense.

Without proper blind testing, how do you know that the op-amp swap improved it? How do you know whether you really heard a difference or just thought you did?

 

[Deleted member 3116]

Perhaps it's confirmation bias. All humans are susceptible to it.

perhaps it isnt. while humans are susceptible to confirmations bias, the human ears are capable of detecting the smallest changes in sound... sometimes changes that are difficult/impossible to measure with existing instruments. The human ear/brain is a very unreliable but very powerful tool, and like any sense it can be honed with practice.

 

[gvl]

you dont own this DAC and have zero experience with op amps , how does anything you say on this subject hold any value? could you try leaving the discussion to amirm or at least be a bit more civilised in how you respond.

Also it wasnt clear in the ''final follow up'' were the measurements from Hifime with the same unit or a different unit?
if its the same then all the original measurement are potentially inaccurate, if its different then the

Finally, the main point was to help someone who already owns this DAC, its pretty much impossible to sell it now so improving it for few a extra dollars makes sense. above all else it was a fun process...

Do you really think that if the designer couldn't properly put the thing together using the actual datasheets and his experience and validate it with measurement equipment your dropping in a random opamp can improve things in a meaningful way? Every crappy opamp out there should be able to put out way over 70db SINAD, the opamp isn't the issue here. Yes you can try to polish the turd, a better recourse IMO is to just suck it up and move on.

 

[Jimmy]

As gvl says the problem here is not opamp related, OPA2134 are very good and even used in expensive equipment too.

What you are hearing when replacing opamps may well be placebo effect or even worse, the result of oscillation. Any decent opamp used correctly should be audibly transparent.

Blindly replacing opamps without having an oscilloscope at hand and/or the neccesary knowledge is not a good idea.

 

[Deleted member 3116]

I didn't see him say anything to that effect.

Without proper blind testing, how do you know that the op-amp swap improved it? How do you know whether you really heard a difference or just thought you did?

I meant listening experience, not electronic experience, which was an assumption based on the inital responses I received. it was wrong to assume anything.

Blind testing this is impossible and with the current instability issue no conclusion can be made yet, frankly real measurements would be a lot more interesting than these essentially worthless subjective impressions but dont have equipment for it.

 

[dc655321]

the human ears are capable of detecting the smallest changes in sound... sometimes changes that are difficult/impossible to measure with existing instruments

Can you provide some examples of "difficult/impossible to measure" acoustic phenomena that instrumentation cannot detect?

 

[Deleted member 3116]

Do you really think that if the designer couldn't properly put the thing together using the actual datasheets and his experience and validate it with measurement equipment your dropping in a random opamp can improve things in a meaningful way? Every crappy opamp out there should be able to put out way over 70db SINAD, the opamp isn't the issue here. Yes you can try to polish the turd, a better recourse IMO is to just suck it up and move on.

Agreed, the op amp is small part of a much larger problem. edit: Im fairly new to high level audio and this was my first time exploring the objectivist's approach, after reading a lot in past day ( and listening to my 'bad' uda38 pro compared to my 'good' ODAC) Im skeptical of what measurements can tell you about the actual sound, I think if people spent more time listening and less time measuring they may discover something that exists outside the ideal world of objectivism .
I already own a AudioQuest DAC and ODAC, the UDA38 sounds significantly better (even in terms of realism)than both these DACs even though it probably measure far worse. The user Wushuliu noted also that this DAC does sound nice. it will be a while till I can afford a D50 so spending a few dollars in an attempt to improve it a bit seems like the best thing to, it feels better than abandoning a $250 purchase at least.

 

[Veri]

Not saying it will be that drastic of a difference, but we did have this whole thread a couple months ago on the topic. Do Audio Op-Amps sound different. Though the results of that are mildly questionable, as the thread gets into discussing the study's setup.

Fair point I hope a follow-up with measurements of op-amp swaps by @amirm will hopefully show some (lack of) evidence as to what could change in terms of sound.

 

[gvl]

The user Wushuliu noted also that this DAC does sound nice.

Vinyl records have a similar dynamic range as this DAC and many think they sound nice, so entirely possible...