Alien DAC v1.1 Construction Thread
Jan 3, 2008 at 9:06 AM Post #992 of 1,562
You might just need to skip C22, C32 and R32 to use those MIC5200 and use the 4.8V model for the 5V, the rest looks pin compatible with the board
smily_headphones1.gif
 
Jan 4, 2008 at 4:58 AM Post #993 of 1,562
Hey all,

Sorry if this has been answered before, but had a couple of quick questions on this.

1) Can this be used as a "plug-and-play" device, eg. I can plug it in to a Windows machine and it will automatically be recognised, OR do I have to use asio4all drivers?

2) How reliable are the latest versions of the asio4all drivers? I've heard very bad things about the driver stability in the past.


Thanks,


Dave
 
Jan 4, 2008 at 5:25 AM Post #994 of 1,562
1) It's plug and play into any machine - Windows, Linux, Apple. ASIO4All is recommended, but no required.

2) If you have problems with it, get v1.8 off the AlienDAC site.


Quote:

Originally Posted by purplepencil /img/forum/go_quote.gif
Hey all,

Sorry if this has been answered before, but had a couple of quick questions on this.

1) Can this be used as a "plug-and-play" device, eg. I can plug it in to a Windows machine and it will automatically be recognised, OR do I have to use asio4all drivers?

2) How reliable are the latest versions of the asio4all drivers? I've heard very bad things about the driver stability in the past.


Thanks,


Dave



 
Jan 8, 2008 at 7:24 AM Post #996 of 1,562
i just finished the kit that i got from jeff.
everything mounted correctly with no bridging but when i plug it in to the usb port, i got unrecognized device.
frown.gif

what steps needed to troubleshoot this?

thanks
 
Jan 8, 2008 at 1:06 PM Post #1,000 of 1,562
Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif
I'm about to order a kit from Jeff, what are the pros & cons of unregulated vs fixed regulated vs adjustable regulated? I'm sure this has been discussed before somewhere but I searched and couldn't find what I was looking for.


Regulated should be chosen in any case. I can guarantee that connecting into a powered, but unregulated USB hub results in bad effects to the sound quality.

The real question seems to be USB-powered regulated (~4.8V with a REG101/102-A) vs. battery-powered 5V regulation (REG101/102-5). It seems that those who have tried both report no difference. So, I would opt for the REG101/102-A and use the extra resistors as described in the link that MisterX provided.
smily_headphones1.gif
 
Jan 10, 2008 at 4:48 AM Post #1,001 of 1,562
I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting.
 
Jan 10, 2008 at 6:15 AM Post #1,002 of 1,562
Quote:

Originally Posted by johnanderson /img/forum/go_quote.gif
I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting.



Well, it uses a PCM2704 vs the PCM2702, so it has lower SNR and I runs a single power supply for analog and digital which might make it slightly more noisy. I can only imagine what output caps are being used in that thing and I doubt it's anything good.
 
Jan 10, 2008 at 6:42 AM Post #1,003 of 1,562
Quote:

Originally Posted by johnanderson /img/forum/go_quote.gif
I'm considering ordering jeff's kit and building it myself but I'm wary of smd soldering. Has anyone compared the alien to the headphonia dac cable found here?

USB Cable 50'' (125cm)

They're pretty much the same price and for the cable I wouldn't have to put in as much work building it and troubleshooting.



i can't answer your question specifically, because i haven't compared the two in terms of sound quality, but a couple of observations:

1) that usb cable DAC doesn't look terribly robust - it actually looks like they just throw heat-shrink over the pcb in the middle of the cable and call it a day. sure, it's small, self-contained and convenient, but it looks like you might be able to snap it by looking at it the wrong way. maybe i'm misinterpreting the pics on the site and the middle is actually covered in some molded plastic, in which case this criticism doesn't apply.

2) as FallenAngel points out, you have much less control (i.e., none at all) over the quality of the components that go into that DAC. sure, the chip is quite similar to the one found in the Alien, but the iPod is a perfect example of the negative effects that some crappy caps can have when placed in the signal path. if i'm not mistaken, the iPod uses an excellent Wolfson DAC, but sullies up the sound going to the headphone jack with some sub-par capacitors downstream. Jeff's kit already includes some nice, high-quality parts, but you can improve on them even more for very little added cost by throwing in, say, a pair of 47uF BG NX Hi-Q output caps. this ability to customize the Alien is a huge advantage, especially since the passive parts in the cable DAC probably aren't the best.

3) once you get into it, SMD soldering is quite fun. the Alien is the only SMD project i've done, but i find myself wanting to buy another kit from Jeff just because i want to do some more SMD work. if you're a DIYer at heart, go ahead and give it a shot - the worst that can happen is that you lose $37, which is precisely what would happen if you accidentally snapped that flimsy-looking cable DAC. on the other hand, the best that can happen is that you get a DAC that (almost certainly) outperforms the cable by a significant margin, and you have the satisfaction of knowing that you put it together yourself.
smily_headphones1.gif
 
Jan 11, 2008 at 3:26 AM Post #1,004 of 1,562
Quote:

Originally Posted by amb /img/forum/go_quote.gif
"High" is relative. HD580 is 300 ohms, which is considered a high-impedance headphone. But the Alien's PCM2702 would really strain at driving a 300 ohm load. It'd be much happier driving a load impedance that's 10x higher or more. After all, it's a line out that was intended to "see" the input of another amp stage.


Yes 'high' in relation to headphones. Still it did drove my headphones quite well. A bit lack of power in the low end but I hardly notice it.

I prefer amping it though. We should toe the line and operate under specified conditions
biggrin.gif

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif
You might just need to skip C22, C32 and R32 to use those MIC5200 and use the 4.8V model for the 5V, the rest looks pin compatible with the board
smily_headphones1.gif



And increase C21/31 to 1uF.

MisterX: Thanks for the pin compatible suggestion. I can't find REG101s anywhere.

I can get 3.3V MIC5200 but they're twice REG101's price. I think its cheaper to hotwire an LM317 regulator offboard but afraid I won't get the same performance.
 
Jan 11, 2008 at 4:04 AM Post #1,005 of 1,562
There are lots of pin-compatible options you should look at before resorting to the messy and vastly inferior LM317 to replace these regulators.

For example, TI offers the TPS732xx series (TPS73201 adjustable, TPS73233 3.3V fixed) that's pin compatible (but requires different setting resistors for the adjustable one). It's not quite as good as REG101 (very slightly worse noise performance, significantly worse PSRR). Biggest caveat is that its absolute maximum input is 6V, so you may need a preregulator if you're not powering from USB.

National has the LP2985 with similar specs (and allows up to 16V input), but no adjustable version (3.3V and 5V are available).

There are more of course, but most SOT23-5 regulators use this same pinout, so browse around and look for ones with similar specs to the REG101.
 

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