[audiofil]

The ES9022 is mounted on the board with the volume pot and orange caps (it's the 16 pin chip).

 

[HeadphoneAddict]

Quote:

Originally Posted by audiofil /img/forum/go_quote.gif Actually we do. Here are some pictures of Icon Mobile's innards: NuForce Icon Mobile New Case - a set on Flickr The output stage is discrete using SMD transistors (SOT-23 package). I presume uDAC is very similar.

Like I said, they don't use opamps in the amps, and uDAC is similar.

Quote:

Originally Posted by ITau /img/forum/go_quote.gif Hello again from me... my baby uDAC is nicely singing for past 10 or so days. I must say i am pretty much satisfied with it so far. And if any of you people are wondering how this baby looks inside, here is a peek... snip 2. Shouldn't there be ESS tech somewhere inside? I heard that this dac is based on ES9022 but i do not see any print like that... does this mean that nuforce has custom printed chips from ESS??

They have custom printed chips in the uDAC and HDP.

 

[audiofil]

I've just taken apart my uDAC to have a better look at the components, especially the output stage.
My best guess: as ES9022 is a V-out DAC (no I/V necessary) the output stage is either passive or non-existent. I cannot figure out what the 3 electrolytic caps are doing there as the ESS data sheet mentions - "no DC blocking capacitors required"

For RCA out it seems to have a sort of a buffer, the 14 SMD chip.

So, my earlier guess about transistor based output stage does not apply to uDAC.

 

[mmerrill99]

Quote:

Originally Posted by ITau /img/forum/go_quote.gif Hello again from me... my baby uDAC is nicely singing for past 10 or so days. I must say i am pretty much satisfied with it so far. And if any of you people are wondering how this baby looks inside, here is a peek... Also got 2 ?. 1. What kind of caps are these? "A" ? Never heard of it.... do you guys think that this thing would benefit from some audigrade caps inside? 2. Shouldn't there be ESS tech somewhere inside? I heard that this dac is based on ES9022 but i do not see any print like that... does this mean that nuforce has custom printed chips from ESS??

Firstly, mods, why do I get only sporadic notifications of postings to this thread?

Excellent ITau, I knew somebody would be tempted to take it apart. Just looking at it I'm pretty certain this is the ESS9022 & I see somebody said that Nuforce have confirmed this so why do they bother with hiding the part ID?

The analogue outs appear to be fed directly into a vol pot. Can anybody tell what resistance range this pot has - should be printed on it if not erased

So no caps or active components in the output path.

I've also run ESS9022 DAC Vouts directly into headphones & it works very well although it shouldn't according to the datasheet which states minimum impedance of 5K. Still, datasheets don't always tell the full story.

 

[ayz]

just out of curiosity, how much power does the uDAC drain? Has anyone tried comparing battery life on their macbook playing music through the headphone jack vs with the uDAC plugged in? I bought an HDP for my main desktop system so I will probably return the uDAC. I've considered keeping it around as a portable laptop headphone amp, but not if it's going to kill my battery life.

I can't do this test myself since my thinkpad T61 battery is already crap (like maybe 2 hrs life) and I'm waiting on the new i7 macbook pros before buying one.

 

[mmerrill99]

Quote:

Originally Posted by audiofil /img/forum/go_quote.gif I've just taken apart my uDAC to have a better look at the components, especially the output stage. My best guess: as ES9022 is a V-out DAC (no I/V necessary) the output stage is either passive or non-existent. I cannot figure out what the 3 electrolytic caps are doing there as the ESS data sheet mentions - "no DC blocking capacitors required" For RCA out it seems to have a sort of a buffer, the 14 SMD chip. So, my earlier guess about transistor based output stage does not apply to uDAC.

Well done, audiofil.
The three electro caps probably de-couple the voltage pin & also the charge pump & negative pins. Maybe there is some value in upgrading them to better caps but the real limitation of this DAC is the USB receiver - the DAC can only do as good as the digital feed it gets. Is this a TAS1020B chip?

I use a HiFAce 24/192 asynch USB transport feeding I2S to parallel ES9022 DACs driving balanced headphones, Sounds very good

 

[mmerrill99]

BTW, if anybody wanted to tap I2S out of this uDac it's on the 5 pin header beside the ES9022 DAC. So if you wanted to feed I2S into this DAC this is where to do it & if you want to tap I2S coming into this DAC you can get it from the socket that this 5 pin header plugs into

 

[audiofil]

Quote:

Originally Posted by jkeny /img/forum/go_quote.gif Well done, audiofil. The three electro caps probably de-couple the voltage pin & also the charge pump & negative pins. Maybe there is some value in upgrading them to better caps but the real limitation of this DAC is the USB receiver - the DAC can only do as good as the digital feed it gets. Is this a TAS1020B chip?

The USB receiver looks like a PCM2706 (32 pin, TQFP form factor), which makes sense. The TAS chips are 48 pin TQFP chips, afaik

The caps may be worth replacing with some low ESR (Oscon maybe). I have to desolder one, so I can read their capacitance value (impossible to see right now)
This is the only real mod I can think of for uDAC, which I don't think will improve anything too much.

Other than that - build a completely new DAC using the PCB with the ES9022 and feed it with 3.3V and I2S

Just kidding

It's a nice little (actually tiny!!!) DAC for very little money.
If you don't enjoy it, you just buy something else. Plenty to choose from these days.

 

[mmerrill99]

Quote:

Originally Posted by audiofil /img/forum/go_quote.gif The USB receiver looks like a PCM2706 (32 pin, TQFP form factor), which makes sense. The TAS chips are 48 pin TQFP chips, afaik The caps may be worth replacing with some low ESR (Oscon maybe). I have to desolder one, so I can read their capacitance value (impossible to see right now)

careful those caps look to be non-polar - don't swap them for Oscons unless you know where the neg should go - PM me if you need help.

Quote:

This is the only real mod I can think of for uDAC, which I don't think will improve anything too much. Other than that - build a completely new DAC using the PCB with the ES9022 and feed it with 3.3V and I2S

Just what i was thinking

Quote:

Just kidding

I'm not

Quote:

It's a nice little (actually tiny!!!) DAC for very little money. If you don't enjoy it, you just buy something else. Plenty to choose from these days.

 

[ITau]

I have one question....might seem laim but still... I was wondering, since this device has no off mode, is it OK to leave it pluged in all the time (blue led on)?? I mean, i know there is no much things to break here, but not sure wether it makes any difference if its on all the time or not. I use mine mainly with desktop system so its not moved often-no reason to unplug it...

 

[K_19]

For what its worth, I have it plugged in 24/7 and I'm definitely not scared that it's gonna break down on me soon or anything.

It doesn't overheat or anything either and only runs on puny USB power... I don't think there will be any problems.

 

[grokit]

Quote:

Originally Posted by K_19 /img/forum/go_quote.gif For what its worth, I have it plugged in 24/7 and I'm definitely not scared that it's gonna break down on me soon or anything. It doesn't overheat or anything either and only runs on puny USB power... I don't think there will be any problems.

Me 2

 

[analogsonar]

you can just turn it off (the blue l.e.d will stay on) by turning the knob all the way to the left until it clicks--- on another note, upgrading the usb cable put out a cleaner stereo image.

 

[ITau]

Upgrading usb cable to what cable exactly? And how much does this upgrade costs? I have 2 usb cables and I do not seem to notice any difference between them....though they are not any brand name cables... I thought there can be no difference here since those are only digitial bits passing trough cables...

 

[grokit]

Quote:

Originally Posted by analogsonar /img/forum/go_quote.gif you can just turn it off (the blue l.e.d will stay on) by turning the knob all the way to the left until it clicks--- on another note, upgrading the usb cable put out a cleaner stereo image.

Yes, that's actually how mine is when not in use.

Quote:

Originally Posted by ITau /img/forum/go_quote.gif Upgrading usb cable to what cable exactly? And how much does this upgrade costs? I have 2 usb cables and I do not seem to notice any difference between them....though they are not any brand name cables... I thought there can be no difference here since those are only digitial bits passing trough cables...