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MOX active crossover buy

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#121
Hi Tiroth,
I'm not sure I read your sensitivity drawing correctly but it did not appear to predict that the Hi Q stage should suffer from an excess of sensitivity.
For the hi Q stage when q = 1.306 the gain should be set to 1.31 then both EVS&K and MFB should show reduced sensitivity to component tolerance.
Oh I checked the schematic you posted earlier and the software appears to be in error. It suggests the wrong value of resistors and even using those resistors it then compounds the errors by misquoting the actual Qs for both stages.

However I am past that & accept that no one has suggested how to modify the PCB so I am left with unity gain as my only option.
I have now produced an excel spreadsheet for a 4 pole low pass Butterworth filter calculator.
Would anyone tell me how to post it?
 
#122
Andrew, I really don't think that TI's software is broken. Thousands of people have used it since it was released some years ago. I would highly suggest at least looking at it, because it can even find the best values in an arbitrary component range (E6/E12/E24/etc).

Remember that the equal value assumption does not hold for non-equal-value filters. You cannot use the derived EV equations to calculate them!

If you zip your spreadsheet you can attach it using the browse button that is underneath the text box when you post a message.
 
#132
Coulomb,
Perhaps you will change your mind once the manual is complete. 😀

I really don't think it is that complicated; it is harder than something like a gainclone but I think it is actually simpler than figuring out all the jumpers in MOX v1. 😉 I think Andrew is going a bit far afield and making things more complicated than they need to be. It is pretty much plug and chug.

PierreG,
Not yet, but they will be coming eventually. Jens has been nice enough to send me the updated gerbers.
 
#136
Pierre,

I certainly think so. I don't like to talk people into buying the discrete opamp though, because although I think it is better, it certainly isn't as much bang for the buck as the excellant OPA2134 once you factor in parts and time to build it. The opamp is MUCH harder to put together than the crossover.

Beyond that, I'll let more objective parties comment. 😉
 
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