what's the best software for simulate a passive EQ network?

creal · Jan 10, 2013

Hi
All is in the title, i looking for a good software for simulate a passive EQ network.
Actually, i work on the Lang PEQ 2 network, i ordered the inductors to ChiroN.
I compared the caps values found on the lang thread with the pultec EQP.
They are many differences between the two schematics and the calculated values.

So, i think the best way is to use a simulator.
But, which one ? I need your advices.
Thanks

Cyril

ruffrecords · Jan 10, 2013

LTspice is the defacto standard.

Cheers

Ian

audiomixer · Jan 10, 2013

I found that for more complex circuits with (TI) Opamps TINA-TI works nicely too. the user interface is a little different and you get 'virtual instruments' much like in Nationals LabView. this is somewhat easier to use when doing component value testing / adjustment...

- Michael

abbey road d enfer · Jan 10, 2013

creal said:
Hi
All is in the title, i looking for a good software for simulate a passive EQ network.
Actually, i work on the Lang PEQ 2 network, i ordered the inductors to ChiroN.
I compared the caps values found on the lang thread with the pultec EQP.
They are many differences between the two schematics and the calculated values.

So, i think the best way is to use a simulator.
But, which one ? I need your advices.
Thanks

Cyril

Any decent electronic simulation software is adequate for this task.
The issue is to use the right models. Physical inductors are quite complex in fact, particularly high-value ones, for mainly two reasons:
The physical reality of parasitic capacitance must be taken into account. The usual model which lumps all parasitic capacitances in one single element does not work. The way the windings are sandwiched, the interwinding capacitances and the capacitances between winding and core create a number of parasitic resonant circuits, which most of them act above the audio frequencies; however some are audible.
Then the most complex aspect is core saturation. I know it is a current subject on the LTSpice forum. Not getting in too much details, core saturation has two noticeable effects: with the increase of level, THD increases, which leads to the creation of upper harmonics, and the tuning frequency increases too, which creates a shift of the curves.

Rochey · Jan 10, 2013

audiomixer said:
I found that for more complex circuits with (TI) Opamps TINA-TI works nicely too. the user interface is a little different and you get 'virtual instruments' much like in Nationals LabView. this is somewhat easier to use when doing component value testing / adjustment...

- Michael

I'll second this. I've tried LTSpice and TINA, I find TINA easier to use. Just makes more sense to how I'm wired

(Disclaimer, I work at TI... but I'm trying to be as unbiased as possible).