Is it possible to turn my console´s LF bell into a shelf?
« on: November 20, 2018, 03:30:46 PM »
Hey guys,

I have a A&H GS3 mixing console and was wondering if it would be possible to mod it so the LF bell becomes a LF shelf?



gyraf

Re: Is it possible to turn my console´s LF bell into a shelf?
« Reply #1 on: November 21, 2018, 03:55:40 AM »
..dunno.. Maybe try shorting C18 (100nf) and see what happens..?

Jakob E.
..note to self: don't let Harman run your company..

L´Andratté

Re: Is it possible to turn my console´s LF bell into a shelf?
« Reply #2 on: November 21, 2018, 04:07:25 AM »
It is a so called Wien bridge filter but could be a standard Baxandall configuration with removal of c17 and the freq pot (+series resistor), if you lose those components and adjust the other a little, you should get standard shelf but without freq tuning.  :)
But the original version is much more useful (imo).
Strictly amateur since 1973...

Re: Is it possible to turn my console´s LF bell into a shelf?
« Reply #3 on: November 21, 2018, 08:58:03 AM »
Many thanks for your replies, guys.

If I´d be loosing the frequency adjustment this would be a bummer.

abbey road d enfer

Re: Is it possible to turn my console´s LF bell into a shelf?
« Reply #4 on: January 13, 2019, 09:47:53 AM »
It is a so called Wien bridge filter but could be a standard Baxandall configuration with removal of c17 and the freq pot (+series resistor), if you lose those components and adjust the other a little, you should get standard shelf but without freq tuning.  :)
In a standard Baxendall, the LF branch goes to the inverting input, and the HF branch is isolated with a resistor that defines the cornetr frequency in conjunction with the LF capacitor(s). Connecting the LF branch to the non-inverting input, as a degraded version of the Wien bridge topology results in two things:
-It inverts the rotation of the Boost/Cut pot (CW becomes Cut, CCW becomes Boost
-Very reduced amplitude of Boost/Cut

Quote
But the original version is much more useful (imo).
I agree.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

abbey road d enfer

Re: Is it possible to turn my console´s LF bell into a shelf?
« Reply #5 on: January 13, 2019, 09:49:42 AM »
Many thanks for your replies, guys.

If I´d be loosing the frequency adjustment this would be a bummer.
A standard Baxendall can be easily modified for variable frequency.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


 

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