How to properly bypass a filter

Started by YouAre, March 24, 2016, 01:32:31 PM

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YouAre

I'm working on a MIC Preamp kit, which comes with input and output EMI filtering (shematic: https://seventhcircleaudio.com/assets/N72/N72R33/docs/n72_sch-938c7a738d8d4a951255670cc4d2a9b3.pdf )

Looking at the cutsheet of these filters ( http://www.mouser.com/ds/2/54/emi_t_series-76067.pdf , look at #7 on the frequency response chart), I worry that the high end response might be a little muffled. I'd like to test this out by toggling the filter in and out on a switch, and could use some help in doing this in the most efficient and effective way.

Do I want to complete bypass the filter on each line (requiring 2 poles of switching for each inductor, much like pedal true bypass switching) or can I simply jumper across each set of inductors (requiring 1 pole per line)? I would lift the connection if the capacitor from the common terminal.

Simply put, can I simply short these filters or do I need to hard bypass them?

Thank you for your help!

Mark Hammer

Don't mean to embarrass you, but um, you DO realize those graphs are in megahertz, and not kilohertz, right?  Kudos for being mindful of bandwidth, but just exactly how much bandwidth do you need?  :icon_wink:

YouAre

Quote from: Mark Hammer on March 24, 2016, 02:24:01 PM
Don't mean to embarrass you, but um, you DO realize those graphs are in megahertz, and not kilohertz, right?  Kudos for being mindful of bandwidth, but just exactly how much bandwidth do you need?  :icon_wink:

...No I can embarrass myself on my own thank you very much.  :icon_redface:

No but seriously, thank you. Completely missed that "mega" prefix. That rolloff at .5 Mhz (500k) is unacceptable!

But in any case, same question still applies to regular filters. Bypass or short?






Mark Hammer

I don't exactly encourage it, but anyone perusing through the over 23,000 posts I have here will find MANY instances of me doing exactly the same thing.  Over, and over and over....  :icon_rolleyes:

While I have you here, you live in NYC.  Have you seen any of those "art eggs" around town?

YouAre

Quote from: Mark Hammer on March 24, 2016, 09:16:58 PM
I don't exactly encourage it, but anyone perusing through the over 23,000 posts I have here will find MANY instances of me doing exactly the same thing.  Over, and over and over....  :icon_rolleyes:

Like my boss says, "do as I say, not as I do."

Quote
While I have you here, you live in NYC.  Have you seen any of those "art eggs" around town?

I'm usually too focused on being rude to tourists to notice anything fun like that.  :icon_razz: