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Post by roadrunner on Aug 14, 2012 15:24:14 GMT -5
Since all of these except perhaps the XMC-1 will be there at Emofest, what?? XMC-1 wont be there? Yes, the XMC-1 will be at Emofest, but it will not be a production model. Thus you will not be able to buy an XMC-1 during Emofest weekend. Big Dan talked about having spent considerable time in the Emotiva Theater watching movies and listening to music. He also said that would be demo'ing TacT for attendees. Just listen to the latest Podcast for details.
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Post by john57 on Aug 14, 2012 16:15:07 GMT -5
Man, this wait is killing me... I'm thinking about just buying another XDA-1 to hold me over on my 2ch system. I am thinking about getting the XDA-1 to drive my Little Dot VI+ balanced headphone amp which also drives my Tannoy Reveal monitors. I just did not need another headphone amp or pre-amp. I just wanted the DAC itself. One question on the XDA-1 when Emotiva changed the volume program on the units did they changed the maximum gain that the units can deliver? I getting mixed statements on this issue.
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Post by counterpoint on Aug 17, 2012 2:46:21 GMT -5
Just out of curiosity, would it make any sense to include a mic input? How is that problem typically approached when one uses a USB DAC for a PC but needs a mic input? It seems like I'm describing a more complete input/output USB interface.
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Post by counterpoint on Aug 17, 2012 3:49:07 GMT -5
120 db snr is very high! I don't think it will manage that. Though DAC chips may manage those values it's considerably harder to make the entire unit manage them. Some manufacterers just state the DAC chip value as the SNR which is a little misleading. I believe emotiva stated the true values for its DAC. I believe the xda-1 was around 400 but they dropped the price, which I think was the right thing to do when the issues came up (USB limited, lossy volume control). I think what we gain in the xda-2 other than the analog volume control and asynchronous USB2 (reduced jitter) is the headphone amp. The Asus Xonar Essence STX claims a SNR of 124dB for front out, while the DAC it uses (TI Burr-Brown PCM1792A) is rated at 127dB. In reality, one review measured a SNR of 114dB. Personally, I'm hoping for a measured SNR of 115dB. It might be a pipe dream, but there's nothing wrong with that.
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Post by garbulky on Aug 17, 2012 6:08:35 GMT -5
120 db snr is very high! I don't think it will manage that. Though DAC chips may manage those values it's considerably harder to make the entire unit manage them. Some manufacterers just state the DAC chip value as the SNR which is a little misleading. I believe emotiva stated the true values for its DAC. I believe the xda-1 was around 400 but they dropped the price, which I think was the right thing to do when the issues came up (USB limited, lossy volume control). I think what we gain in the xda-2 other than the analog volume control and asynchronous USB2 (reduced jitter) is the headphone amp. The Asus Xonar Essence STX claims a SNR of 124dB for front out, while the DAC it uses (TI Burr-Brown PCM1792A) is rated at 127dB. In reality, one review measured a SNR of 114dB. Personally, I'm hoping for a measured SNR of 115dB. It might be a pipe dream, but there's nothing wrong with that. If it really is 115 db, I would be surprised as that is still a really good measurement. I have the essence st and I really liked it. I felt it did it's best job with room ambience in a recording.
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Post by counterpoint on Aug 17, 2012 9:06:42 GMT -5
The Asus Xonar Essence STX claims a SNR of 124dB for front out, while the DAC it uses (TI Burr-Brown PCM1792A) is rated at 127dB. In reality, one review measured a SNR of 114dB. Personally, I'm hoping for a measured SNR of 115dB. It might be a pipe dream, but there's nothing wrong with that. If it really is 115 db, I would be surprised as that is still a really good measurement. I have the essence st and I really liked it. I felt it did it's best job with room ambience in a recording. I believe I read in the same review that the Xonar Essence ST measured at 102dB SNR, so its not the same as the STX in that regard.
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Post by Entity on Aug 17, 2012 9:39:13 GMT -5
They provide the Audio Precision test report with the cards that does show 124dB. Either way the numbers are pretty good, I enjoy my STX.
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Post by garbulky on Aug 17, 2012 9:50:09 GMT -5
They provide the Audio Precision test report with the cards that does show 124dB. Either way the numbers are pretty good, I enjoy my STX. I like mine too. Great deal. I'm waiting till I get my PC back up so I can compare the two directly. Somebody mentioned to me about a passive pre-amp and I wonder if this would improve the sound if I ran the RCA outs at full on the xonar to the passive pre-amp hopefully bypassing any digital attenuation going on.
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Post by GreenKiwi on Aug 17, 2012 11:40:05 GMT -5
Man, this wait is killing me... I'm thinking about just buying another XDA-1 to hold me over on my 2ch system. I am thinking about getting the XDA-1 to drive my Little Dot VI+ balanced headphone amp which also drives my Tannoy Reveal monitors. I just did not need another headphone amp or pre-amp. I just wanted the DAC itself. One question on the XDA-1 when Emotiva changed the volume program on the units did they changed the maximum gain that the units can deliver? I getting mixed statements on this issue. My understanding is that the reprogramming just changed the curve, not the start or end points, so the max volume will be the same.
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Post by garbulky on Aug 17, 2012 12:01:18 GMT -5
Man, this wait is killing me... I'm thinking about just buying another XDA-1 to hold me over on my 2ch system. I am thinking about getting the XDA-1 to drive my Little Dot VI+ balanced headphone amp which also drives my Tannoy Reveal monitors. I just did not need another headphone amp or pre-amp. I just wanted the DAC itself. One question on the XDA-1 when Emotiva changed the volume program on the units did they changed the maximum gain that the units can deliver? I getting mixed statements on this issue. The xda-1 appeared to overdrive my xenos 3ha headphone amplifier. It distorted on moderate volumes and the sound appeared very thin and unrealistic. My xenos is supposed to be able to handle a maximum of 6.7V input. The product page says the xda-1 produces 12 V peaks. I used a 12db RCA voltage attenuator and that made a significant difference even though it didn't fully cure it. Now at loud volumes there's still distortion. On my upa-2 this problem isn't quite there in the same way. However, adding the 12 db attenuator to my upa-2 produced a different sound signature which was more pleasing to my ear. It sounds less "compressed" at high volumes but the difference is very subtle. In movies with the attenuator the subtle change in sound signature wasn't as pleasant but for music it was. I too am interested too in the actual maximum gain that is being produced. Your experience might be difference because your HA appears to be of much higher quality than mine.
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sorbe
Sensei
"Don't cross the streams..."
Posts: 673
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Post by sorbe on Aug 17, 2012 12:47:35 GMT -5
I'm using the XDA-1 + UPA-200 to drive a pair of 4 ohm near-field speakers on my desktop PC. So, I've heard that the XDA-1 needs to be set to "80" to avoid digital distortion from their volume control, BUT setting the XDA-1 volume that high will push up to 12 Volts at the amp? And then it will likely distort in analog domain because it presents too high a voltage at the amp(which likes 1-2 Volt peak nominally)? And that's regardless of whether I use a small class T amp like the Dayton DTA-100a or a class AB amp like the Emotiva UPA-200? Is there really a good reason to push out 12 volts out of the XDA- 1 pre-amp output?? This is probably why I've had to RMA my DTA-100a due to losing one channel after just a month. Is my UPA-2 next to be RMA'ed unless I keep the XDA-1 digital volume way down (like <50) to avoid random PC sounds peaking high and damaging my speakers or amp?? I've heard that the XDA-2 will have a digital volume control to tame the digital clipping. What about the potential for serious analog distortion in the XDA-2 due to 12 volts peak pre-amp out.
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Post by garbulky on Aug 17, 2012 13:14:50 GMT -5
I'm using the XDA-1 + UPA-200 to drive a pair of 4 ohm near-field speakers on my desktop PC. So, the XDA-1 needs to be set to "80" to avoid digital clipping, but setting the XDA-1 volume that high will push up to 12 Volts at the amp? And then it will likely distort in analog domain because it presents too high a voltage at the amp(which likes 1-2 Volt peak nominally)? And that's regardless of whether I use a small class T amp like the Dayton DTA-100a or a Emotiva UPA-200? Is there really a good reason to push out 12 volts out of the pre-amp output?? This is probably why I've had to RMA my DTA-100a due to losing one channel after just a month. Is my UPA-2 next to be RMA'ed unless I keep the digital volume way down to avoid random PC sounds peaking high?? :/ I've heard that the XDA-2 will have a digital volume control to tame the digital clipping. What about the potential for serious analog distortion in the XDA-2 due to 12 volts peak pre-amp out. Here's the specs: Nominal output voltage: 1V RMS Peak output voltage: > 12VRMS (balanced) So the 12 V output is for the balanced section not for regular unbalanced which is likely less. Also keep in mind that it does 12 V on PEAK not as standard. Running from my upa-2 I had good results even without the attenuator. My main concern was for my headphone amplifier which distorted badly at volumes I knew it had no trouble with. After the attenuator this problem was reduced greatly though not fully. I've had my upa-2 for a few years now and it hasn't shown any sign of quitting or any problems whatsoever. It also has never clipped on me though it gets slightly compressed sounding at high volumes. If you like, you can try the atttenuator I mentioned to see if you like the change in sound. I found it best for music but not for movies.
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Post by john57 on Aug 17, 2012 19:03:48 GMT -5
post=429917 time=1345221605] I am thinking about getting the XDA-1 to drive my Little Dot VI+ balanced headphone amp which also drives my Tannoy Reveal monitors. I just did not need another headphone amp or pre-amp. I just wanted the DAC itself. One question on the XDA-1 when Emotiva changed the volume program on the units did they changed the maximum gain that the units can deliver? I getting mixed statements on this issue. I do not see the issue with the 12v peaks using my Little Dot VI+ which is a powerful all tube headphone amp. The XDA-1 will be driving the balanced inputs of the amp. The signal first will be going to the ALPS RK168 4Channel Potentiometer then to the input of the driver tube of my VI1+. My Little Dot VI+ is currently set for the low gain range by jumpers in the amp that were set at default at the factory. The Xenos 3ha uses op-amps on its inputs and it would be hard for an op-amp to handle peaks greater than the supply voltage. On the Xenos 3ha the bass and treble knobs control the equalization gain of the op-amps. Once you overload the input stage adjusting the volume control may not have any effect depending on how the circuit is designed. Success using the XDA-1 seems to depend on what is controlling the input stage of the device in question. Knowing the input impedance is not enough to tell how well two devices will interact. I find out on Monday when my XDA-1 comes in. Thanks greenkiwi for your input. My understanding is that the reprogramming just changed the curve, not the start or end points, so the max volume will be the same.
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Post by garbulky on Aug 17, 2012 21:25:18 GMT -5
Greenkiwi: Your post is very interesting to me. I would like to get some more information. I shall Pm you. Thanks.
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KeithL
Administrator
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Post by KeithL on Aug 20, 2012 15:31:52 GMT -5
The output signal on the XDA-1 will not normally exceed 2 VRMS with a real digital input. "12v" is the peak level that the output stage can deliver cleanly (which shows it has lots of headroom) but you should never see it with a real-world signal. A digital volume control works by making the numbers smaller when you turn down the level (just like the quiet sounds on a CD use less bits because the numbers are smaller). Therefore, if you end up with your system playing at full volume while the XDA-1 is turned way down, you will be listening to a signal with less bits of resolution - which may have a negative effect on sound quality. (The same thing would happen if you recorded a CD where the loudest portions were at -30 dB instead of -3 dB). To avoid losing some resolution with the XDA-1, it would be better to put an analog attenuator in line with the output (or turn down the volume control on the equipment you're connecting it to - most analog equipment with a volume control places the volume control potentiometer right after the input, and should be virtually immune to volume control overload). It is not, however, tragic to have the XDA-1 turned down a little bit. I'm using the XDA-1 + UPA-200 to drive a pair of 4 ohm near-field speakers on my desktop PC. So, I've heard that the XDA-1 needs to be set to "80" to avoid digital distortion from their volume control, BUT setting the XDA-1 volume that high will push up to 12 Volts at the amp? And then it will likely distort in analog domain because it presents too high a voltage at the amp(which likes 1-2 Volt peak nominally)? And that's regardless of whether I use a small class T amp like the Dayton DTA-100a or a class AB amp like the Emotiva UPA-200? Is there really a good reason to push out 12 volts out of the XDA- 1 pre-amp output?? This is probably why I've had to RMA my DTA-100a due to losing one channel after just a month. Is my UPA-2 next to be RMA'ed unless I keep the XDA-1 digital volume way down (like <50) to avoid random PC sounds peaking high and damaging my speakers or amp?? I've heard that the XDA-2 will have a digital volume control to tame the digital clipping. What about the potential for serious analog distortion in the XDA-2 due to 12 volts peak pre-amp out.
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KeithL
Administrator
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Post by KeithL on Aug 20, 2012 15:38:12 GMT -5
A volume control potentiometer is a passive device, and so isn't susceptible to overload, nor to overload distortion. The only way you could damage it would be to actually overheat it, which would take an awful lot of voltage. Most analog devices with volume control potentiometers put the pot first after the input. Therefore, if your Little Dot, like most analog equipment with a volume control, puts the volume control pot first, then you absolutely want to run the XDA-1 at 80 and control the level with the LD's volume control. If, however, the input goes straight to a gain stage, then it absolutely will be subject to overload. post=429917 time=1345221605] I am thinking about getting the XDA-1 to drive my Little Dot VI+ balanced headphone amp which also drives my Tannoy Reveal monitors. I just did not need another headphone amp or pre-amp. I just wanted the DAC itself. One question on the XDA-1 when Emotiva changed the volume program on the units did they changed the maximum gain that the units can deliver? I getting mixed statements on this issue. I do not see the issue with the 12v peaks using my Little Dot VI+ which is a powerful all tube headphone amp. The XDA-1 will be driving the balanced inputs of the amp. The signal first will be going to the ALPS RK168 4Channel Potentiometer then to the input of the driver tube of my VI1+. My Little Dot VI+ is currently set for the low gain range by jumpers in the amp that were set at default at the factory. The Xenos 3ha uses op-amps on its inputs and it would be hard for an op-amp to handle peaks greater than the supply voltage. On the Xenos 3ha the bass and treble knobs control the equalization gain of the op-amps. Once you overload the input stage adjusting the volume control may not have any effect depending on how the circuit is designed. Success using the XDA-1 seems to depend on what is controlling the input stage of the device in question. Knowing the input impedance is not enough to tell how well two devices will interact. I find out on Monday when my XDA-1 comes in. Thanks greenkiwi for your input. My understanding is that the reprogramming just changed the curve, not the start or end points, so the max volume will be the same.
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KeithL
Administrator
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Post by KeithL on Aug 20, 2012 15:51:24 GMT -5
The XDA-1's digital volume control loses resolution when turned down very LOW. There is no "digital clipping" involved. With a full-level digital input, the XDA-1 puts out around 2 RMS - NOT 12 V. Honestly, this is only as issue if your amp has very high gain (or if you're using the XDA-1 with a preamp), and you end up turning your XDA-1 down to a very low level and then boosting the signal at the preamp or amp - in which case it might sound a tiny bit "grainy"..... we are NOT talking about clipping or anything getting damaged here... The XDA-2 will have a digitally controlled analog stepped volume control to avoid losing resolution, even at very low listening and volume setting levels. That means that, if your system has high gain, and so you want to run the volume on the XDA-2 set to a low level, you will not lose any resolution by doing so (it will basically be pretty much the same as using a passive attenuator). Since there's no reason to avoid using the XDA-2's volume control aggressively, you can set the output level to anything that makes your downstream equipment happy.... with no loss of audio quality. Keith I'm using the XDA-1 + UPA-200 to drive a pair of 4 ohm near-field speakers on my desktop PC. So, I've heard that the XDA-1 needs to be set to "80" to avoid digital distortion from their volume control, BUT setting the XDA-1 volume that high will push up to 12 Volts at the amp? And then it will likely distort in analog domain because it presents too high a voltage at the amp(which likes 1-2 Volt peak nominally)? And that's regardless of whether I use a small class T amp like the Dayton DTA-100a or a class AB amp like the Emotiva UPA-200? Is there really a good reason to push out 12 volts out of the XDA- 1 pre-amp output?? This is probably why I've had to RMA my DTA-100a due to losing one channel after just a month. Is my UPA-2 next to be RMA'ed unless I keep the XDA-1 digital volume way down (like <50) to avoid random PC sounds peaking high and damaging my speakers or amp?? I've heard that the XDA-2 will have a digital volume control to tame the digital clipping. What about the potential for serious analog distortion in the XDA-2 due to 12 volts peak pre-amp out.
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Post by AudioHTIT on Aug 20, 2012 16:14:18 GMT -5
Informative comments Keith (also in the other thread), one desirable feature that's not expected in the XDA-2 is an HT bypass - might it be in the Pro-DAC? Can you share any other information comparing the two?
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Post by counterpoint on Aug 20, 2012 17:23:42 GMT -5
Is the XDA-2 going to have a 1/4" headphone jack?
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Post by ribbonking on Aug 20, 2012 20:25:45 GMT -5
Is the XDA-2 going to have a 1/4" headphone jack? Yes, the XDA-2 will have a 1/4" jack based on what I saw at THE Show in Newport Beach. However, the new Pro Dac with have two each 1/8" headphone jacks.
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