Alien DAC v1.1 Construction Thread - Page 67

YESSSS!
Very nice! I'll look into these. Thank you!

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

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

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.

Thanks for the substitute. I wish they also had an adjustable device.

I am waiting until FEB for a small shipment of REG 102 UA-A.
TI had to mess up a good thing.

Any other possibilities?

help needed

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.

what steps needed to troubleshoot this?

thanks

Check voltages at 5V and 3.3V. How is this powered?

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.

You're right, it has been covered before.

Alien DAC - Parts List



I have not found anything that is pin compatible.

Have you tried a parts broker?
Like SGI direct for instance:
SGI - Electronic Components Parts Distributor - Call 978-922-4299

(they have thousands of them listed as available but.....)

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.

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.

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.

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
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.

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.