Uptone ISO Regen Review and Measurements

[Jinjuku]

Yes, I plan to do that. I only have one though.

One's evidently enough and pretty much the same as the others for the exhibited behavior.

 

[amirm]

Here you go. I tested the Schiit Modi 2 with the ISO regen which we all know from previous review, lives up to its name for providing little protection from PC noise into its output (http://audiosciencereview.com/forum/index.php?threads/budget-dac-review-schiit-modi-2-99.1649/).

As we see from the two graphs in red/yellow with ISO Regen, it helped this DAC massively. Gone are the skirt around our main tone which indicates removal of random noise. The deterministic tones (spikes) are also reduced in level substantially although not gone completely.

The addition of ISO Regen takes the Modi Schiit from pretty horrible performance (in this day and age) to very respectable! This shows clear advantage of galvanic isolation in PC DACs. Do not buy a DAC without it.

So kudos to UpTone ISO Regen for doing what it says it is doing (in part), i.e. provide good isolation between the PC and DAC.

Edit: Improvements seem to be purely a function of better USB power and not anything else. See further measurements below.

 

[amirm]

Needless to say, the above confirms fully the poor design of Schiit DAC and our previous measurements showing the same. Measurements work in bringing out features and performance of audio products.

 

[amirm]

While I had everything setup, I ran the test with iFi iDAC2 which like Schiit Modi 2 runs from USB power:

As noted, this is a well designed DAC with full isolation from the PC and hence addition of ISO Regen does nothing for it.

 

[amirm]

And before Jinjuku asks me , here is Behringer UMC204HD measurements with and without ISO Regen:

As we see, this $70 full featured DAC is of no need of external isolation either. Performance is excellent with or without UpTone ISO Regen.

 

[amirm]

So summarizing, if you buy a DAC blind, based on subjective remarks and without measurements, you could wind up with a DAC like Schiit which has no/little isolation from the PC. In that case the isolation ISO Regen provides is very much helpful. In the case of any other DAC whose measurements show clean implementation (vast majority of them), the ISO Regen is not necessary.

The power of measurements here is undeniable in how it can show a case for and against this product. That the manufacturer does not conduct such tests is to their detriments as much as their customer as they could have easily used the Schiit Modi 2 as an example of what it could do.

Also note that I find no evidence of it cleaning up the USB signal with its USB hub is of any value. Short distances of USB do not need any repeater capability. Cheaper devices with just the isolation chip should provide similar benefit to likes of Schiit Modi 2 DAC.

 

[Sal1950]

Needless to say, the above confirms fully the poor design of Schiit DAC and our previous measurements showing the same.

Probably covered elseware but I thought I'd ask anyway.
IYHO, how much would the noise present in the shitt DAC without a ISO would be actually audible on even Class A level gear?
So then that question would extend to would the removal of said noise then produce a audible improvement?
Or is this all just technically superior conjecture?

 

[DonH56]

Nice job Amir! So it does work as advertised, although the benefits occur with a compromised (poor) DAC, which makes sense. Poor design has probably led to a lot of tweaks that only work when you start with cra... err, less-robust components.

 

[amirm]

IYHO, how much would the noise present in the shitt DAC without a ISO would be actually audible on even Class A level gear?
So then that question would extend to would the removal of said noise then produce a audible improvement?

Good question. Did a quick test with and without and I can't tell the difference. I also played with the front switch on ISO regen and again could not detect much.

That jives with psychoacoustics that says that wide skirt is masked by our main tone. And at any rate, nearly 0 db 12 Khz tone is not something that exists in music.

The other distortion products are too low level to be audible.

So yes, you have a good point that the audible improvements may not be there with ISO Regen. Indeed this may be the reason many have bought the Schiit Modi 2 and not complaining about any obvious fidelity problems.

More, careful testing is needed to know definitively.

 

[Sal1950]

If you still have things set up, I'm curious as to the effect the ISO would have on the shitt with the isolation switch disabled?

 

[amirm]

Hmmm. I may have to eat my earlier words if my assumption of the little switch on ISO Regen is right. Here is measurements with that switch in either position:

As we see performance (improvement) is the same. According to what I read, this switch defeats the galvanic isolation. If so, then the isolation is not doing anything. And the resulting improvement must then come from cleaning up the USB power.

Would have to take the unit apart to see what the switch really does.

 

[amirm]

If you still have things set up, I'm curious as to the effect the ISO would have on the shitt with the isolation switch disabled?

You read my mind. See my post right past yours.

 

[Sal1950]

I appalud them for including galvanic isolation in this release but I have to then question the switch. Why on earth would anyone want to disable isolation if it is available?

Actually know the answer to my own question. It gives the crowds at CA, WBF, etc; something to play with, talk about the veils lifted and soundstage expanded, yadayadayadada.
I can just hear them carrying on already, having an orgy of subjective orgasmic listening experiences. Ain't this a fun hobby. LOL

Ha Ha, I hit the nail on the head in my first post.
The switch doesn't do a damn thing except to be food for the audiophools. LOL

 

[Blumlein 88]

Hmmm. I may have to eat my earlier words if my assumption of the little switch on ISO Regen is right. Here is measurements with that switch in either position:

View attachment 8045


As we see performance (improvement) is the same. According to what I read, this switch defeats the galvanic isolation. If so, then the isolation is not doing anything. And the resulting improvement must then come from cleaning up the USB power.

Would have to take the unit apart to see what the switch really does.

If we are looking for cleaned up noise, which clearly is not very high in level either way, it might be worthwhile to reduce your test tone to -60 db similar to how an SNR test is done. Any noise intrinsic to the devices/connections not related to the signal might be revealed. My opinion is you'll see nothing either way, but it would make sense to look for it that way.

 

[Jinjuku]

And before Jinjuku asks me , here is Behringer UMC204HD measurements with and without ISO Regen:

View attachment 8044

As we see, this $70 full featured DAC is of no need of external isolation either. Performance is excellent with or without UpTone ISO Regen.

I wasn't going to ask Just want to see if even more performance is wrung out of $79 with balanced output.

 

[Jinjuku]

So summarizing, if you buy a DAC blind, based on subjective remarks and without measurements, you could wind up with a DAC like Schiit which has no/little isolation from the PC. In that case the isolation ISO Regen provides is very much helpful. In the case of any other DAC whose measurements show clean implementation (vast majority of them), the ISO Regen is not necessary.

The power of measurements here is undeniable in how it can show a case for and against this product. That the manufacturer does not conduct such tests is to their detriments as much as their customer as they could have easily used the Schiit Modi 2 as an example of what it could do.

Also note that I find no evidence of it cleaning up the USB signal with its USB hub is of any value. Short distances of USB do not need any repeater capability. Cheaper devices with just the isolation chip should provide similar benefit to likes of Schiit Modi 2 DAC.

Do you have a self powered USB hub that you could replace the uptone with and see if it does anything?

 

[amirm]

Do you have a self powered USB hub that you could replace the uptone with and see if it does anything?

Have you guys bugged my brain without me looking??? I was driving to Best Buy store to buy a new camera body and on the way there I thought I should pick up a hub and see how it does with that!

The hub is a four port "Insignia" (Best Buy private brand) for USB 2.0. It comes with external wall wart switching power supply. I got ripped off to the tune of $29 plus tax .

Anyway, here are the results:

The faded dark green curve is the Schiit Modi 2 DAC directly connected to the PC. As before, it shows all kinds of sins with wide skirt of random noise and peaks to the left and right of that.

The line in purple is the USB hub with its external power supply. As you see, what it giveth on one hand, it taketh away with the other! It reduced the low frequency noise some but added pretty massive correlated humps of its own. Ugly.

Next I tried the hub in self-powered mode, that is, no external power supply. This resulted in the Cyan colored graph which shows a big improvement over doing nothing, or using the external switching power supply.

For the last measurement I popped the top open, soldered a couple of wires to its supply line and powered it from my linear lab supply. As you see in the bold, light green curve, this showed the best improvement with this hub.

For reference, I am showing the UpTone ISO Regen results in red. It produces the best performance.

Not much to celebrate for ISO Regen though as it is absolutely clear that the Schiit Modi 2 suffers from poor filtering of its USB power. It is hugely sensitive to what is going there. A clean, post regulator inside of the Schiit Modi 2 would have produces the best performance with no need for anything external.

That means you can implement your own good power by getting a USB cable that separates USB power and feed that with a clean linear power supply. That would probably cost $30 or 1/10th the price of ISO Regen.

Better yet, avoid this Schiit Modi 2 DAC. Can't believe a company that brags about their designer heritage can't create the clean power inside the DAC. But you knew that.

 

[Jinjuku]

Have you guys bugged my brain without me looking??? I was driving to Best Buy store to buy a new camera body and on the way there I thought I should pick up a hub and see how it does with that!

The hub is a four port "Insignia" (Best Buy private brand) for USB 2.0. It comes with external wall wart switching power supply. I got ripped off to the tune of $29 plus tax .

Can you try the psu from the Regen?

 

[Sal1950]

it is absolutely clear that the Schiit Modi 2 suffers from poor filtering of its USB power. It is hugely sensitive to what is going there. A clean, post regulator inside of the Schiit Modi 2 would have produces the best performance with no need for anything external.

I really don't mean to indulge in a bash fest of anyone, and possibly I cover this in the another thread if so I'm sorry but I find this situation extremely curious. There are few out there (AFAIK) with more experience and background in building DAC's than Mike Moffat, I was aware of his work with Theta going as far back as the 1980s. How does this happen that a $79 component can exhibit such superior numbers in the area of noise?. Did he focus his time and available $money in other areas that left these shortcomings as a matter of decided compromise?
I don't get it.

 

[amirm]

Can you try the psu from the Regen?

Would take some work as the connector on the hub is oddball (tiny). But I can try. The thing is though that the ISO Regen has post regulators in there that produce the USB bus voltage output. So I don't think there is magic in its external power supply.