[K3cT]

At that price, it will directly compare with the Gamma1. I wonder how that one will go.

 

[Pomeitsu]

I was expecting uDAC to drive my dt-990 pro (250 ohm) better than Icon integrated (as I need to turn the latter to at least 3 o'clock to get a decent volume); seems I was wrong. As I am now thinking to move to Stax SR 404, I am thrilled to find Larry's way of using Icon to drive Stax via SRD-7 transformer. The question is: where to source SRD-7? Can anyone help? Thanks.

 

[HeadphoneAddict]

Quote:

Originally Posted by Pomeitsu /img/forum/go_quote.gif I was expecting uDAC to drive my dt-990 pro (250 ohm) better than Icon integrated (as I need to turn the latter to at least 3 o'clock to get a decent volume); seems I was wrong. As I am now thinking to move to Stax SR 404, I am thrilled to find Larry's way of using Icon to drive Stax via SRD-7 transformer. The question is: where to source SRD-7? Can anyone help? Thanks.

Sorry, the Icon integrated amp does have more power for driving high impedance phones, or inefficient phones. Apparently the uDAC seems to handle the HD600 decently, but it struggles with my 600 ohm AKG K240M and HiFiMan HE-5, one from each of those two categories. I would also not expect much from a K701 or 600 ohm Beyer/AKG either. I am still burning it in and will report more later with more phones.

There is a nice SRD-7 Mk2 in the FS forum right now that you should jump on. That would be the way to go for the SR-404, which will kill the DT990!

 

[daigo]

I've had the uDAC for a few days now and it can definitely handle its own as a headphone amplifier with my low impedance a900's. The increase in transparency from the uDAC compared with just using the EF2's usb DAC is very noticeable, especially with classical music or male voices. However, I still prefer the added warmth to the midrange by feeding rca's to the EF2 from the uDAC.

For $99 plus tax, I think the uDAC is an excellent entry level DAC or as a usb/SPDIF converter for a mid-fier like myself.

 

[burgunder]

Quote:

Originally Posted by daigo /img/forum/go_quote.gif I've had the uDAC for a few days now and it can definitely handle its own as a headphone amplifier with my low impedance a900's. The increase in transparency from the uDAC compared with just using the EF2's usb DAC is very noticeable, especially with classical music or male voices. However, I still prefer the added warmth to the midrange by feeding rca's to the EF2 from the uDAC. For $99 plus tax, I think the uDAC is an excellent entry level DAC or as a usb/SPDIF converter for a mid-fier like myself.

So the uDAC is a step up from the DAC build into the EF2, that's very interesting as I am looking for a DAC to improve the sound from my EF2. Could you say anything about whether the bass responce improves or not, I have a pair of AKG K400's and they could use a little boost in the bass department.

 

[Scott_Tarlow]

So does this mean the Pico is obsolete?

 

[HeadphoneAddict]

Quote:

Originally Posted by Scott_Tarlow /img/forum/go_quote.gif So does this mean the Pico is obsolete?

No.

 

[HeadphoneAddict]

Quote:

Originally Posted by burgunder /img/forum/go_quote.gif So the uDAC is a step up from the DAC build into the EF2, that's very interesting as I am looking for a DAC to improve the sound from my EF2. Could you say anything about whether the bass responce improves or not, I have a pair of AKG K400's and they could use a little boost in the bass department.

It's warm but mostly neutral sounding, so it's not a bass boost device.

 

[ramus]

How would you compare uDAC's headphone out to D4's?Especially using Grados?

Thanks

 

[HeadphoneAddict]

Quote:

Originally Posted by ramus /img/forum/go_quote.gif How would you compare uDAC's headphone out to D4's?Especially using Grados? Thanks

The uDAC is a little warmer and more forward with Grados, which is better for my RS-1 than my HF-2, but I could use it with both. The D4 is a little thinner sounding with my RS-1 than I think is optimal, but also acceptable and very good with my HF-2.

 

[mrarroyo]

Larry, would you please confirm that the RCA out is fixed and only the headphone out is changed by the volume control. Thanks.

 

[HeadphoneAddict]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Larry, would you please confirm that the RCA out is fixed and only the headphone out is changed by the volume control. Thanks.

NO, the DAC feeds the volume pot first, and then sends audio into the RCA or the headphone amp AFTER the volume. I did mention in the review that the volume pot allows volume matching with other DACs. According to Nuforce it is an ALPS "quality" attenuator and has minimal impact on the sound quality.

The bonus is that you can use the uDAC to control the volume of a speaker amp that has no volume control, such as the RWA stereo power amp 30.2 to pair with some K1000 or speakers. And it allows you to turn the DAC's output level down in case your amp has a low volume channel imbalance in the volume pot, as this will let you turn the amp's volume control up higher and get it away from any low volume channel imbalance.

Note - the RCA out turns off when the headphones are plugged in, so your speaker amp on the RCA out will not play at the same time as your headphones. I suspect that having the DAC chip's output driving two amps at the same time could affect the sound because that would change the amp input impedance that the DAC chip sees. The DAC is not using any opamp buffers or caps, so the only thing between the DAC and the amp is the volume pot.

And the S/PDIF coax out is activated only when the volume knob is turned off completely, because the USB receiver chip cannot still feed I2S to the high-end internal DAC at the same time that it sends S/PDIF out to the RCA coax jack. To do that the internal DAC would have to be using S/PDIF also, but they didn't want to go S/PDIF internally since I2S is better, so a choice had to be made there too.

 

[burgunder]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif It's warm but mostly neutral sounding, so it's not a bass boost device.

I wasn't looking for bass boost as such but just wondering whether the internal DAC of the EF2 migth have some roll of in the bass meaning that the uDAC would improve the bass.

Hearing that the RCA output is connected to the volume pot makes me wonder what Nuforce means when they say "High voltage 2V analog output". Another thing that I'm wondering is that the DAC chip migth be the ES9022 Sabre but that is of course only guessing.

 

[HeadphoneAddict]

Quote:

Originally Posted by burgunder /img/forum/go_quote.gif I wasn't looking for bass boost as such but just wondering whether the internal DAC of the EF2 migth have some roll of in the bass meaning that the uDAC would improve the bass. Hearing that the RCA output is connected to the volume pot makes me wonder what Nuforce means when they say "High voltage 2V analog output". Another thing that I'm wondering is that the DAC chip migth be the ES9022 Sabre but that is of course only guessing.

I don't have permission to reveal what the DAC chip is right now, sorry, but it is confidential. But, the "High voltage 2V analog output" is the RCA output which is stronger than any of the iBasso DAC line out, and it comes direct from the DAC chip output.

The uDAC is strong down to 16Hz with my phones that will play that low. I don't hear any roll-off.

 

[HeadphoneAddict]

UPDATE - I received a final production uDAC today, and I compared it to the pre-production unit that I reported on. I am very happy to report that there is NO HISS with my very sensitive Westone IEM and I am tickled pink! It sounds even better with my ES3X now that it has a blacker background. The hiss wasn't an issue with the JH13Pro and UE11Pro, and now it is no longer an issue with the Westone IEM either.