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In the Forum: Audio Discussions
In the Thread: Multi-amping crossovering.

Post Subject: Internal line level XO applied inside ML2Posted by skushino on: 6/11/2012

I'm working on a project that may be of interest to others, and thought posting to this old thread was a better way than beginning a new post.

I use speaker level passive crossovers, between multi-amps (not DSET) and drivers. My desire is to move the filters from speaker level to line level, and to move them inside the amp. The current speaker level crossovers are first order, caps or coils, depending on application, plus a voltage divider to attenuate the MF. There seem to be two methods to apply filters inside the power amp, 1) locate the filters at the amp input, before the gain stages, and 2) locate the filters in between gain stages. If I understand correctly, the advantage of option 1 is simplicity (at least for me) - I can calculate filter component values based on the measured or published input impedance of the power amp. The advantage of option 2 is the opportunity to use less components by combining coupling and filter capacitor values.

Is this understanding correct?

For an example of option 1, if I wanted to add a 70hz high pass filter in the ML2 with a 41k input impedance, then a cap of .0568uf is all that's required, correct?

If I want the filter located in-between gain stages, for the benefit of reducing component count, I have no idea how to proceed. Wouldn't this require a circuit schematic?

For those who have experience, am I on the right track, or over complicating? I like the idea of going with option 2 in the interest of having one less cap in the signal path, but I only feel confident working with option 1 now.

Thanks for any clarifying replies.

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