hifi said:
I haven't been getting an outpouring of design confirmation here. Has anyone really looked at the circuit? Someone needs to review the design to make sure that the CS8420 and CS43122 are configured for correct operation, and that the pull-up/down resistors are of an acceptable value.
Changes in this revision:
<ul>
<li>Added a 75Ω BNC input with transformer coupling.
<li>Added one more ferrite bead
<li>Reduce board size to 9in<sup>2</sup>
<li>Correct input on 43122 mute pin
</ul>
<a href="http://atari.saturn5.com/~jwb/43122/schematic.png">Schematic</a>
<a href="http://atari.saturn5.com/~jwb/43122/manuf.zip">Gerber and Drill files</a>
<img src="http://atari.saturn5.com/~jwb/43122/ss-cont.png">
<ul>
<li>Added a 75Ω BNC input with transformer coupling.
<li>Added one more ferrite bead
<li>Reduce board size to 9in<sup>2</sup>
<li>Correct input on 43122 mute pin
</ul>
<a href="http://atari.saturn5.com/~jwb/43122/schematic.png">Schematic</a>
<a href="http://atari.saturn5.com/~jwb/43122/manuf.zip">Gerber and Drill files</a>
<img src="http://atari.saturn5.com/~jwb/43122/ss-cont.png">
In reply to a question I recieved by email:
The power supplies are left to the discretion of the builder. In the single groundplane version, there is one entry point for +10V/0V/-10V. This is flexible, and you could easily use +/-12V or +/-9V instead. In the split groundplane version, there is a top entry point for +10V/0V/-10V, and two entry points in the digital section for +10V/0V. For the digital supplies (lower half of the board) you could use anything from +7V to +20V.
The power supplies are left to the discretion of the builder. In the single groundplane version, there is one entry point for +10V/0V/-10V. This is flexible, and you could easily use +/-12V or +/-9V instead. In the split groundplane version, there is a top entry point for +10V/0V/-10V, and two entry points in the digital section for +10V/0V. For the digital supplies (lower half of the board) you could use anything from +7V to +20V.
Updated bill of materials is here:
http://atari.saturn5.com/~jwb/43122/bom.html
The cost to build two of these boards would be about $280 for parts and $80 for boards. Without shipping costs that is only $180 each.
I think I will go ahead and build a couple of these suckers. Does anyone want a board to play with? The prices are much better in quantity
Edit: The parts price comes down by $28 if I substitute ZTX450 for ZTX869. The 869 is <em>way</em> overkill and costs a lot.
http://atari.saturn5.com/~jwb/43122/bom.html
The cost to build two of these boards would be about $280 for parts and $80 for boards. Without shipping costs that is only $180 each.
I think I will go ahead and build a couple of these suckers. Does anyone want a board to play with? The prices are much better in quantity
Edit: The parts price comes down by $28 if I substitute ZTX450 for ZTX869. The 869 is <em>way</em> overkill and costs a lot.
I ordered boards from PCB Express. They are two-sided with plated through holes and no solder mask. The power supplies are built and tested. I suspect I will have a working prototype in mid-November, assuming the design is correct.
I'm still worried that 4.7kΩ pull-up resistors may have been the wrong choice.
I'm still worried that 4.7kΩ pull-up resistors may have been the wrong choice.
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