gavgomad Posted August 21, 2008 Author Report Share Posted August 21, 2008 Nice to know I wasn't too far off! ;-)Well, it seems to me that logically we should follow the datasheet and go with 33k/20k solution also used on the 3378/3379. At least that way we know that the filter should be responding appropriately to a 0-5v control signal. ;-)Maybe, as you say, there is a different CV scale going on inside the Xpander.... All the more reason to go with the datasheet given that we're coming straight out of the DACs and can set our own upper and lower limits and scaling both with the hardware trimmers on the DAC board, and in the software.As an update, I have been working in my spare time on a dual 3372 board (still plugging in the schematic into Eagle - itself a slow go!). As per a recommendation from one of the good lads on the SDIY list, I'm using a single DG403 and DG407 to handle the switching on both filters, with 3x TL-074 and a TL-072. It's gonna be a nightmare to layout, but I'll take my time and see what I can do! ;-PI have all of the switching circuit plugged in as a schem, and one of the 3372 filters (went with the datasheet!) - one more to go! Will post the plugged in schem when I'm done so my work can be checked and parts decisions made before we move on to layout.As for the Obie caps, I'll give the 3389 sheet a look.... The caps selected appear to be the same as the 3372 datasheet, but for the switched in 100pF in place of one of the .033uF in half of the modes. Quote Link to comment Share on other sites More sharing options...
Enth Posted October 16, 2008 Report Share Posted October 16, 2008 Any news on this one? 8) Quote Link to comment Share on other sites More sharing options...
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