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Alien DAC v1.1 Construction Thread - Page 86

post #1276 of 1560
6/30/08 at 2:24am
Quote:
Originally Posted by Pars View Post
The formula for the -3dB cutoff point on a filter (high pass in this case) is:

f = 1 / 2 * Pi * R * C

where C is in farads.

So for example, your 0.47uf cap with a 100K resistor to ground would give:

1 / 2 * 3.14159 * 100000 * 0.00000047

or 3.39 Hz

The filter will have some effect up to an octave or so above this.
Hi pars,

I'm fiddling around with the comparison between the .47uf caps and the 33uf caps. I'm not getting the same numbers when I do this calculation, though. I'm getting 0.073827365! If I halve it again, I'll get closer, with 0.0369136825.

Ehm...what am I missing? Thanks!
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post #1277 of 1560
6/30/08 at 9:04am
Quote:
Originally Posted by bhjazz View Post
Hi pars,

I'm fiddling around with the comparison between the .47uf caps and the 33uf caps. I'm not getting the same numbers when I do this calculation, though. I'm getting 0.073827365! If I halve it again, I'll get closer, with 0.0369136825.

Ehm...what am I missing? Thanks!
A couple of parentheses :
f = 1 /( 2 * Pi * R * C)
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post #1278 of 1560
6/30/08 at 11:55am
Quote:
Originally Posted by tomb View Post
A couple of parentheses :
f = 1 /( 2 * Pi * R * C)
Oh yeah, parentheses... sorry about that! I just automatically calculate a formula like that as if the parens were there. Thanks for pointing that out Tom.
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post #1279 of 1560
7/1/08 at 1:21am
Hahaha! Well, cool. Thanks, you two.
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post #1280 of 1560
7/1/08 at 2:51am
Just installed the Muse ESs. Yow, baby! I know there's some break-in ahead, but the bass is excellent. Just what I was looking for. Even my HD600s have a good, solid, bass foundation from a PC source. Neat! I'd also like to mention how clean the rest of the audio band sounds. Excellent start and stop from top to bottom. Geez, Donald Fagen's Morph the Cat...thud! This is damn cool. Can't wait until they break in some more. Thanks for the tips!
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post #1281 of 1560
7/2/08 at 3:46pm
Quote:
Originally Posted by bhjazz View Post
Just installed the Muse ESs. Yow, baby! I know there's some break-in ahead, but the bass is excellent. Just what I was looking for. Even my HD600s have a good, solid, bass foundation from a PC source. Neat! I'd also like to mention how clean the rest of the audio band sounds. Excellent start and stop from top to bottom. Geez, Donald Fagen's Morph the Cat...thud! This is damn cool. Can't wait until they break in some more. Thanks for the tips!
At first, I was overwhelmed by the bass but really really liked it too! but that wore off and something was lacking.. I followed in TomBs footsteps and bypassed the ESs with some sonicap Gen IIs that I had. Wait till you do that!
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post #1282 of 1560
7/2/08 at 4:45pm
Ah yes....I do have some Gen IIs waiting, but I want to break these in first to get a good idea of how they sound. I found a few tunes last night that were maybe a bit thick in the bass. I imagine a week or so of break in will do the trick for the ESs.

I did hear one thing that I really found odd. With Foobar and Asio output, before each tune I hear the initialization (I think...or the initial storage sequence)...it sounds like "bththbth". I don't think I heard it with Foobar and Wave Out. Does anyone else get this? I've got XP Pro. It's not terribly loud, but strangely irritating!
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post #1283 of 1560
7/10/08 at 4:53pm
Hello,

I'm trying to build an alien dac using jeff rossell's kit

however, I m having a little difficulty understanding something :

i populated ic2 and ic3 with my low soldering skills

but i decided to check the pins to see if there was a short circuit somewhere

so I checked pins and got 0 ohms between nearby pins which to my understanding, meant that there was a short circuit

I decided to remove ic2 and ic3 and cleaned the solder with a desoldering braid

however, I still get the 0 ohms reading between some pins of ic2 and ic3. Example : between the two top left pins of IC2.

so I was wondering if it was normal because those pins were somehow connected by the board, or if it was because somehow, my soldering operation had left some sort of residue that kept the pins connected together

thanks in advance for your answer
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post #1284 of 1560
7/10/08 at 5:14pm
http://www.myexposition.com/diy/usbd...atic-1.0-4.png

On IC2 & 3 Pins 5,6,7 & 8 are all connected
and so are pins 1 & 2
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post #1285 of 1560
7/10/08 at 6:58pm
ugh, so it was normal. Well, thanks a lot for the tip ^^
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post #1286 of 1560
7/12/08 at 2:40am

Replacing smd caps gone walkabout...

I regret the cheap antistatic tweezer set I bought. One pair snapped and the other pair slipped and tossed c15 across my desk. I found it once, but not the second time.

To my mild surprise, Electronics Plus in San Rafael is not too far and they carry smd caps that look equivalent ( item C1687 on the page Electronics Plus - Hard to find parts and accessories, available and ready to ship! ).

My question is, do I need to worry about matching the other parts of the kit I purchased from Glass Audio, or are these apparently same-spec caps likely to be an OK replacement? Same .1uF value, voltage, etc., but who knows if its the same part. Could it matter?

Thanks in advance...
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post #1287 of 1560
7/12/08 at 6:31am
The 0.1uF caps are pretty generic, they serve for power supply decoupling only so their value and type is pretty non-critical. Any value from 0.01uF to 0.1uF should be fine, and they're operated at low voltage (5V or less). The only thing I would think about is that that site doesn't list the dielectric used in those capacitors, I don't know what's used in the Glass Jar kit, but the ones at that site might be inferior. As I said above though, the value of these caps is not critical at all, so even if they have very poor temperature stability (the consequence of using an inferior dielectric) I'm sure they'd be fine.

Make sure they're the right size, but they will otherwise be fine. They should be 0805 size. It looks from the photo like they might be 1206 which are larger and might be difficult to fit, but it's hard to tell.
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post #1288 of 1560
7/14/08 at 1:45am
Thanks, error 401 -- your suspicion was right, I called and they are the 1206s and you saved me an hour in the car. Better yet, daylight revealed the wayward part under my desk.

I plowed ahead today and got it all assembled. I find the SMD capacitors almost impossible to solder down neatly. I have huge hands and find working with objects the size of two grains of sand a particular challenge. Lots of soldering and resoldering. When I finally plugged it in (voltages checked out) and then got zip on audio out I figured I'd melted something or had an invisible disconnect somewhere or a bridge in one of my sticky solder cellpools and despaired of ever figuring out what is wrong.

But it turned out I'd just missed a switch in OSX to use the Burr-Brown for output and it works! Sounds great. The bass is excellent (listening to Percy Heath's "Suite for Pop" right now...) I'm just delighted. Can't wait to get it cased up.

Thanks again to this fabulous community for another rewarding project.

__Roy
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post #1289 of 1560
7/14/08 at 7:20am
Just want to comment that Vitamin Q bypassed Black Gate Nx hi-qs in CR and CL sound beautiful.
I have a few aliens here so I a/bed the just Black Gate to the version with Vitamin Qs and the Qs really bring the magic. In fact they've taken me from being lukewarm about the alien to really loving it
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post #1290 of 1560
7/14/08 at 1:55pm
Very cool! What values are your CL/CRs and VitQs (can't seem to read the values in the pic)?

I have some .18uF VitQs from beezar and my onboard CL/CRs are 33uF Nichocons. Any reason anyone can think of that these would or wouldn't be worth a try in combination? (I'm particularly nervous and clueless about the potential for defeating the circuit-protection role of the CL/CR caps).
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