Mogens, I looked in detail at the graphs I got from LTspice and the ones you got from KiCad I think it is.
The individual graphs for the SW out and ESL out are very much the same with very little differences.
The thing that I don't like is the dip I see if I combine the two, then I see the dip at around 100Hz.
I think it is a phase thing, where the two paths are in opposite phase at around 100Hz.
Jan
The individual graphs for the SW out and ESL out are very much the same with very little differences.
The thing that I don't like is the dip I see if I combine the two, then I see the dip at around 100Hz.
I think it is a phase thing, where the two paths are in opposite phase at around 100Hz.
Jan
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Hi Jan,
There must still be an error in my schematic. If you look at the screen-shot I send you of the two curves in same plot it seems to me that each output has 100 degrees opposite phase so I assume they would sum to near 0 degrees. If I plot the same with the LTspice file you send they are not the same. I must clearly have made some corrections like the 15nF error in my simualtion. It's very annoying that I can't find it 😡
I will try find the error.
Mogens
There must still be an error in my schematic. If you look at the screen-shot I send you of the two curves in same plot it seems to me that each output has 100 degrees opposite phase so I assume they would sum to near 0 degrees. If I plot the same with the LTspice file you send they are not the same. I must clearly have made some corrections like the 15nF error in my simualtion. It's very annoying that I can't find it 😡
I will try find the error.
Mogens
Hi Jan,
I have been looking at the board again and I believe your sim is correct with the 15n fix. Also, the designer of the MT2001 filter writes that he measured the phase of the ESL and SW to be 90 degrees out of phase. I do not know if he measured that at the electrical output of the Gradient filter.
However, with speakers one always has to measure the acoustic output as the speaker units them self are not linear and therefore also introduce som phase shift. But, I do not know if that makes any difference here.
Mogens
I have been looking at the board again and I believe your sim is correct with the 15n fix. Also, the designer of the MT2001 filter writes that he measured the phase of the ESL and SW to be 90 degrees out of phase. I do not know if he measured that at the electrical output of the Gradient filter.
However, with speakers one always has to measure the acoustic output as the speaker units them self are not linear and therefore also introduce som phase shift. But, I do not know if that makes any difference here.
Mogens
Mogens, if you have some time someday maybe you could do a freq sweep of the two outputs of the board. Then we would know.
If you were closer I'd come and borrow the filter but that seems a bit extreme 😎
Jan
If you were closer I'd come and borrow the filter but that seems a bit extreme 😎
Jan
I counted all the tuning caps per value on the board and it matches the schematic. Reading the resistors is a bit harder.
But I believe the schematic to be corrrect.
Jan
But I believe the schematic to be corrrect.
Jan