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.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
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.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.


 

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