Emotiva Stealth DC-1 DAC
Sep 7, 2014 at 12:29 PM Post #421 of 903
In case anybody is interested, they provide measurements here  http://emotiva.com/resources/media/Stealth/DC1_AP_Report.pdf
 
I'm drawn to this DAC because it seems reasonably priced for what you get.  I've gone through the thread, and didn't see any concrete numbers on the output impedance.  Anybody know or measured it?  I'm interested in the output impedance to drive my iems.
 
Sep 8, 2014 at 12:17 PM Post #422 of 903
There's a lot of confusion about "asynchronous MODE" and "using an asynchronous sample rate CONVERTER" (and the way we named the options in the DC-1 doesn't help the confusion).
 
With the original type of USB connection (properly referred to as "an isochronous USB connection"), the audio signal clocking is controlled by the computer. This type of connection has a lot of jitter, and is known for not sounding very good. Some low-cost DACs these days still use isochronous USB - but better ones do not. Virtually all good quality DACs these days instead use what's properly called "an asynchronous USB connection". In an asynchronous USB connection, the DAC clocks the signal instead of the computer. Because of this, the amount of jitter depends on how good the USB input clock on the DAC is - but even the poorest DACs do far better in this regard that a computer. Both our XDA-2, and our DC-1 have asynchronous USB connections. (Note that this affects ONLY the USB input since it describes ONLY the USB input circuitry.) 
 
An asynchronous sample rate converter (ASRC) is a hardware device (although it can be done in software) which takes an input signal and re-clocks it. The ASRC takes in your original digital audio signal, and a new "clean" clock, and it puts out a new digital audio signal which is equivalent to the original signal, except that it is at the sample rate of the new clean clock. Most ASRCs use a single fixed-frequency clock for their "clean clock", and so convert the incoming signal (whatever sample rate it starts out as) to that fixed new sample rate; the purpose of the conversion is to eliminate jitter by re-clocking the signal to the clean clock; the rate conversion is actually "a side effect" of the process involved. This is the way the ASRC in our XDA-2 works. The ASRC in our DC-1 is a lot more sophisticated. The DC-1 actually detects the original sample rate, and then creates a new clean clock for the ASRC that matches that original rate. (So the DC-1 "converts" the signal to the same sample rate as it started out - but using a new and cleaner clock. This therefore avoids any possible change in the way the audio sounds that might occur BECAUSE you were changing the sample rate, but still removes the jitter.
 
The USB input on the DC-1 is ALWAYS in asynchonous USB mode. When you select "asynchronous mode" in the menu, you are selecting "ASRC enabled"; when you select "synchronous mode", you are DISABLING the ASRC. While the terminology we used is technically correct AS REFERS TO THE OPERATION OF THE DAC ITSELF, it does NOT refer to the USB input mode, and so can be somewhat confusing. When you enable the ASRC in the XDA-2 or the DC-1, it is applied to ALL inputs; the ASRC re-clocks and so removes the jitter from ALL INPUTS including USB, Coax, Toslink, and AES/EBU. (Since the asynchronous USB input should be quite free of jitter anyway, you shouldn't expect enabling the ASRC to make much if any difference in sound when you're using the USB input, but you can turn it on (or leave it turned on) if you like - and it shouldn't hurt anything.)
 
Without getting into a long discussion about whether changing the sample rate will be audible, using the ASRC should NOT introduce hum, noise, or hiss into the digital audio stream. We have received a few reports of DC-1 units which seem excessively sensitive to noise only when the ASRC is enabled.... or that actually produce hum or buzz only when the ASRC is enabled. This is NOT due to the action of the ASRC itself, but rather due to the fact that the circuit paths inside the DC-1 change when you enable the ASRC, which affects the grounding of the analog audio circuitry. If your DC-1 makes hum or buzz when the ASRC is enabled, and this changes when you select different sample rates on the computer, then either your DC-1 itself is faulty (and so digital noise is bleeding through into the analog circuitry internally), or your DC-1 is faulty in a different way, and so is being unusually sensitive to ground or power supply noise from your computer (and so you are "hearing" the difference in noise produced by your computer at different sample rates THROUGH the DC-1.)
 
This is not normal operation for a DC-1, and you should NOT hear hum or noise on the DC-1 when the ASRC is engaged (not at ANY sample rate).
 
Sep 8, 2014 at 1:55 PM Post #423 of 903
There are two different "asynchronous" concepts here.
 
1. Asynchronous USB - The DC-1 always uses this (at least in UAC 2.0 mode)
2. ASRC or Asynchronous Sample Rate conversion - this is where the DC-1 resamples the incoming data to essentially remove jitter.  this is what they are talking about switching between.
 
Sep 10, 2014 at 6:19 AM Post #425 of 903
I have a question: How powerful is the pre-amplifier in the Stealth DC-1? How does it compare to other popular budget amps such as the Magni, Vali, O2, etc...?

 


did you mean how powerful is the headphone amplifier of the Stealth DC-1?

I can't find the specs of the headphone amp..but I am pretty sure I saw it before on the emotiva forum..
 
Sep 10, 2014 at 8:42 AM Post #426 of 903
  I have a question: How powerful is the pre-amplifier in the Stealth DC-1? How does it compare to other popular budget amps such as the Magni, Vali, O2, etc...?

The pre-amp is solid sound wise. With remote, you have to learn not to turn it up too fast. While individual clicks take too long. It's an art to master.
 
If you meant headphone amps, then it's decent enough for high sensitivity dynamics. I'd take DC-1 headphone amp for easy to drive cans over O2. You get a nice bass kick from DC-1's headphone amp.
 
Sep 10, 2014 at 10:44 AM Post #427 of 903
 
  I have a question: How powerful is the pre-amplifier in the Stealth DC-1? How does it compare to other popular budget amps such as the Magni, Vali, O2, etc...?

 


did you mean how powerful is the headphone amplifier of the Stealth DC-1?

I can't find the specs of the headphone amp..but I am pretty sure I saw it before on the emotiva forum..

 
 
  The pre-amp is solid sound wise. With remote, you have to learn not to turn it up too fast. While individual clicks take too long. It's an art to master.
 
If you meant headphone amps, then it's decent enough for high sensitivity dynamics. I'd take DC-1 headphone amp for easy to drive cans over O2. You get a nice bass kick from DC-1's headphone amp.

 
Sorry guys, I did mean the headphone amp itself for driving headphones. I was wondering if it had enough power to drive a pair of more fickle headphones such as my K712s.
 
Sep 10, 2014 at 11:14 AM Post #428 of 903
   
 
 
Sorry guys, I did mean the headphone amp itself for driving headphones. I was wondering if it had enough power to drive a pair of more fickle headphones such as my K712s.

 
  1. Impedance @ 1kHz: 62 ohms
  2. Sensitivity: 105 dB SPL/V

 
I just pulled up the stats on the 712 pros from headphone.com. 
 
The impedance is at 62 ohms but with a high sensitivity. I think it could work. Hopefully you can find someone with the particular combination. The Emo headphone amp is quite clean and transparent. I briefly used mines on the first day with my D2000 and it sounded pleasant, before I moved it to my home theatre rig.
 
Sep 10, 2014 at 11:33 AM Post #429 of 903
   
  1. Impedance @ 1kHz: 62 ohms
  2. Sensitivity: 105 dB SPL/V

 
I just pulled up the stats on the 712 pros from headphone.com. 
 
The impedance is at 62 ohms but with a high sensitivity. I think it could work. Hopefully you can find someone with the particular combination. The Emo headphone amp is quite clean and transparent. I briefly used mines on the first day with my D2000 and it sounded pleasant, before I moved it to my home theatre rig.


I have posted on the k712 thread in the headphones section, but no one with that combo has replied yet. This DAC with pre-amp/headphone amps features interests me since it will only use one power plug socket. I only have one socket available on my surge protector so that be very convenient for my needs. Plus I have read on here it is a bargain for its price, with SQ comparable to higher end DACs like the Schiit Gungnir.
 
Sep 10, 2014 at 12:15 PM Post #430 of 903
 
I have posted on the k712 thread in the headphones section, but no one with that combo has replied yet. This DAC with pre-amp/headphone amps features interests me since it will only use one power plug socket. I only have one socket available on my surge protector so that be very convenient for my needs. Plus I have read on here it is a bargain for its price, with SQ comparable to higher end DACs like the Schiit Gungnir.

Well in that case if you can pull for a Dangerous Source, I'd pick that over the DC-1. I have both and would definitely pick Dangerous Source each time where headphones are concerned. Both are DAC/AMP/PRE-AMP combo.
 
Sep 10, 2014 at 12:24 PM Post #431 of 903
  Well in that case if you can pull for a Dangerous Source, I'd pick that over the DC-1. I have both and would definitely pick Dangerous Source each time where headphones are concerned. Both are DAC/AMP/PRE-AMP combo.

$500 is my absolute limit for a DAC, so the dangerous source is not an option. Plus, it would be way too wide for my desktop.
 
I think I am straying this thread off-topic. Sorry guys, and thanks for the advice.
 
Sep 10, 2014 at 12:53 PM Post #432 of 903
 
  I have a question: How powerful is the pre-amplifier in the Stealth DC-1? How does it compare to other popular budget amps such as the Magni, Vali, O2, etc...?

 


did you mean how powerful is the headphone amplifier of the Stealth DC-1?

I can't find the specs of the headphone amp..but I am pretty sure I saw it before on the emotiva forum..

 
Power output:
750 mW into 8 ohms
1200 mW into 32 ohms
180 mW into 300 ohms
90 mW into 620 ohms
 
Sep 14, 2014 at 2:00 AM Post #433 of 903
I have decided to try out this DAC/AMP combo. Now I need to know which specific cable/adapter I will need to connect the DC-1 to my computer/sound card. I have a 3.5 mm to 3.5 mm stereo cable that was used to connect my amp to computer. An RCA cable will not work for the sound card. Thanks.
 
Sep 14, 2014 at 2:23 AM Post #434 of 903
  I have decided to try out this DAC/AMP combo. Now I need to know which specific cable/adapter I will need to connect the DC-1 to my computer/sound card. I have a 3.5 mm to 3.5 mm stereo cable that was used to connect my amp to computer. An RCA cable will not work for the sound card. Thanks.

Are you trying to connect the DC-1 to your computer through digital or analog connections? Why not just connect the DC-1 to your computer via the USB…Am I missing something about your case?
 
Sep 14, 2014 at 3:16 AM Post #435 of 903
  Are you trying to connect the DC-1 to your computer through digital or analog connections? Why not just connect the DC-1 to your computer via the USB…Am I missing something about your case?

 
Yes, there a few details I forgot to mention. Once I receive the DC-1, I will want to connect it through a digital connection with the SoundBlaster Z sound card. I do quite a bit of gaming along with listening to music; connecting the DC-1 to the sound card gives me the surround sound when gaming, so I can get the benefits for both of them.
 
Now, since I never play PVP games and prefer SP & strategy games, I may not necessarily need the surround sound no longer. So I would be open to the USB option if that is less of a hassle.
 

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