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Alien DAC v1.1 Construction Thread - Page 11

post #151 of 1560
8/2/06 at 6:08pm
Can someone recommand a good tweezer for smd work? preferably from digikey?
I looked at the catalogue, and there are cheap ones thats around 3 bux to ones that costs 20 dollars. Is there a big difference? I don't mind paying more for a tweezer if it's going to make my life a lot easier .
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post #152 of 1560
8/2/06 at 6:53pm
Wiha makes a very respectable set of tweezers. I like the fine tip, 30 degree offset ESD set they make, but they have a massive selection of tip offsets, widths, etc. You're pretty much garenteed find something you'll like. Fry's sells a few for $16, well worth the investment in my opinion.

-V
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post #153 of 1560
8/2/06 at 7:06pm
I totally love cross-locking (or clamp?) tweezers. It reaches anywhere on a such small board like this. It holds SMD part on the board so you have both hands free for soldering and no worries that part will move because of your hands or when solder tip touches it. Just have to plan ahead and solder center parts first.

Mine was a part of some tool kit but looks very much like these :

http://www.hobbylinc.com/htm/tes/tes50632c.htm http://www.contenti.com/products/tweezers/470-040.html

Make sure it has fine tip

This one is not good for 0805 parts - tip is too wide http://www.contenti.com/products/tweezers/470-045.html
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post #154 of 1560
8/2/06 at 9:02pm
Quote:
Originally Posted by NeilR
I have what I think are fine tweezers but I had a great deal of trouble getting the ceramic caps to lay flat while I held them with the tweezers. Maybe I need a better set of tweezers. If anyone has specific suggestions for better tweezers, I'd like to hear it.

Regards,
Neil
I'm really happy with the curved XYtonic 7-SA here:
http://www.assemblyoutfitters.com/xytronic/XY-7-SA.aspx

I hold them like a pencil, which keeps my hand out of the way, and pressure is subsequently directed downward.

As much as I like them you must be careful not to launch your components across the room with an uneven grip.
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post #155 of 1560
8/2/06 at 10:09pm
Thread Starter 

Help WANTED

Hi guys,

I have been working on my DAC, but at last I found myself missing R31, a 32.3KOhm resistor. Does anyone else happen to use the same resistor so then you can send me one, and I will pay you back with paypal.

Please PM me if you can help.

Thanks in advance,
Peter
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post #156 of 1560
8/3/06 at 8:33pm

Admin Privelages?

I just put in my order for a few of these boards. I was hoping to use one of them at work (where I don't have admin rights) on a windows machine. Will this work without admin rights, or does a driver need to be installed? I know some things work for normal users, like USB drives.

Thanks,
Garron
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post #157 of 1560
8/3/06 at 8:50pm
Hey NeilR, if you are still having problems with noise try rechecking your solder joints for your ferrites. I had the same problem with my second board, my music was totally unlistenable.

Oh and just for all the alien builders, USB cables do really make a difference on SQ. I purchased a 2nd USB cable from a dollar store. Once I plugged it in, I could definitely tell something was different and off. There was a lot less detail and all the ranges seemed very recessed. I wouldn't say the difference was night and day, but more like a 10-20% variation.

Right now im sticking to my original USB printer cable, until I find something better.

GL w/ your builds and happy listening
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post #158 of 1560
8/3/06 at 9:29pm
Well, I've finally got the last order of parts in, I'm hopefully going to have it together by tomorrow morning. The only thing that scares me is the dac chip, the rest of the smd I'm fine with (I had no trouble doing a PPAS a month ago).
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post #159 of 1560
8/3/06 at 11:41pm

Another Alien DAC comes to life

Here's mine, paired up with a PPAS.



The IC4 pads look messy because I had soldered on a BUF634, but then I changed my mind about how I was going to power it.

I set it up to run off a 9V battery (not the same one as on the PPAS), but it sounded horrible. When I started scoping things, I found that the 5V line had a 140KHz sawtooth coming from somewhere. I couldn't figure out where it was coming from, so I reconfigured it to run off of USB power instead and it seems to work fine.

Now I just have to cram it all into a Hammond 1455C1201 and I'm done!
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post #160 of 1560
8/4/06 at 12:34am
Hi!

I have read both threads about the alien DAC and i have
some stupid questions just to clear things out!

1)AV+ and G2 are for external power source? (battery PSU)
if i don't need to connect external power source are there any
parts i sould left out?

2) OL, OG, OR are the output and the ground? (just to be sure)

3) which of the ICs are critical besides the PCM2702?
so if for some reason i can't find it to leave it out


recently i have finished a project with the PCM2902 but it needs
fine tunning! this is the link if anyone can help i'll be glad!

http://www6.head-fi.org/forums/showthread.php?t=192076
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post #161 of 1560
8/4/06 at 8:05am
Hey guys, is the Pana FC low-impedance-enough for C13?

Rob.
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post #162 of 1560
8/4/06 at 4:47pm
Quote:
Originally Posted by whiz
I have read both threads about the alien DAC and i have
some stupid questions just to clear things out!
Also read Assembly Guide and Parts List pages on the support web site. Many of your questions are answered there.

Quote:
Originally Posted by whiz
1)AV+ and G2 are for external power source? (battery PSU)
if i don't need to connect external power source are there any
parts i sould left out?
If you build Unregulated USB configuration, you should not populate IC3 and IC4. Refer to Assembly guide for more details.

Quote:
Originally Posted by whiz
2) OL, OG, OR are the output and the ground? (just to be sure)
Yes

Quote:
Originally Posted by whiz
3) which of the ICs are critical besides the PCM2702?
so if for some reason i can't find it to leave it out
You need IC1 and IC2 in minimal configuration. In theory if you have 3.3V power supply, you may get rid of IC2.
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post #163 of 1560
8/4/06 at 4:49pm
Quote:
Originally Posted by robzy
Hey guys, is the Pana FC low-impedance-enough for C13?

Rob.
It is. I doubt one can hear any difference with lower impedance capacitors.
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post #164 of 1560
8/4/06 at 9:00pm
Quote:
Originally Posted by Alf
It is. I doubt one can hear any difference with lower impedance capacitors.
Thanks

Rob.
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post #165 of 1560
8/4/06 at 10:18pm
Re: Those ferrite arrays people were talking about back on page 7 - would they have a parallel resistance effect if all pins are soldered in? i.e. would 4x 600R or 4x 75R give 150R and 18.75R (respectively) at 100MHZ (or whatever the spec of the ferrite is?) - or does it not work like that for ferrites?
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