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Old 28th March 2003, 10:57 AM   #11
hifi is offline hifi  Sweden
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Hello,

Nice work, but would you be so kind as to share the cad files? especially if they are eagle, witch by the looks they are? (.sch / .brd)



/micke
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Old 28th March 2003, 02:44 PM   #12
jwb is offline jwb  United States
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Sure, here they are. You'll also need my custom library items.
Attached Files
File Type: zip dac24192cad.zip (52.6 KB, 836 views)
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Old 28th March 2003, 02:50 PM   #13
jwb is offline jwb  United States
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Here's the library items. They turned out to not be that large.

<a href="http://atari.saturn5.com/~jwb/custom-libs.zip">Custom Eagle libraries</a>
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Old 28th March 2003, 08:15 PM   #14
Prune is offline Prune  Canada
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OK, I opened the CAD files in EAGLE, but the bottom layer (blue), instead of being filled in like in your picture, it's just a thick outline. Is this how it's supposed to be? (I needed to open it so I can trim a couple of millimeters off the board size so I can get cheaper deal with the PCB maker).
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Old 28th March 2003, 08:53 PM   #15
jwb is offline jwb  United States
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The ground plane is a polygon. Use the 'ratsnest' command to fill it.

-jwb
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Old 29th March 2003, 11:14 PM   #16
Prune is offline Prune  Canada
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About the power supply: I don't know much about designing power supplies, but if I start with a single wall wart, what would be the total current that the wall wart should be able to supply? Can I have a design where I have a say 24 V wall wart and use two regulators to get the +10 V and -10 V? And what would be appropriate filtering for each section (digital and analog; and should the separation and filtering for each section be before or after the regulators)?
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Old 31st March 2003, 03:51 AM   #17
jwb is offline jwb  United States
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Thanks to diyaudio.com user rpell, who built this circuit and pointed out a few bugs. There was a mistake in the <a href="http://atari.saturn5.com/~jwb/43122.png">schematic</a> listing a 4.7K&Omega; resistor which should be 47K. Also the <a href="http://atari.saturn5.com/~jwb/43122-bom.html">bill of materials</a> has been updated to include R3 and R12 on the 5.5V regulator and a change from ZTX869 to cheaper but still good ZTX450 for the constant current sources. A bug in the layout of the ground plane under the input connector was also fixed.

The question came up of what to do with the ground point near the input connector. This via should be used to attach this ground to the chassis near the input. It should not be connected to the main system ground point.

Here are the updated data for anyone who wants to build this. Besides the fixes, I made one small change: under the clock generator are five pads for a Hirose PCB-mount vertical MMCX connector. You could use this to feed in your favorite clock signal instead of using the on-board clock chip. Could be some good room to experiment there.

Have fun,
jwb
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File Type: zip dac24192cad.zip (53.6 KB, 514 views)
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Old 31st March 2003, 07:05 AM   #18
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Default $ for sonics?

What DACs (separate or inbuilt) can you compare the sound to?

And for the 30 odd parts, including say a regulated wall wart:
what’s the approx total cost?

TIA
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Old 3rd April 2003, 11:32 PM   #19
hifi is offline hifi  Sweden
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This is the dac I want to build, but before sending the boards to be manufactured I would like to here some comments on:

* The groundplanes
* The oscillator clock trace and decoupling
* The spdif routing

All smd is mouted on the bottom of the board and all hole-trough mounted is on the toplayer, The outputstage is based on LL1527 transformers.

And thanks to JWB for sharing the Cad files so I really can mess things up ;-)

/ Micke
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Old 3rd April 2003, 11:45 PM   #20
jwb is offline jwb  United States
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Cool

Can the 43122 drive the line? I went with the follower buffer.
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