2 Band Active EQ Comparison

Stompboxes circuits published in magazines, books or on DIY electronics websites.

2 Band Active EQ Comparison

Postby POTL » 02 Jun 2018, 03:33

Hi
What is the difference between them?
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Re: 2 Band Active EQ Comparison

Postby phatt » 03 Jun 2018, 13:24

The second circuit is slightly better but both are unlikely to be guitar friendly (if that is the intention?) These are more like HiFi tone controls where the mid frequency is centered around 1kHz. The classic guitar tone circuits need the mid point around 400Hz to be useful.
Final outcome depends on what you are wishing to use the circuits for :?:
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Re: 2 Band Active EQ Comparison

Postby poiureza » 06 Jun 2018, 13:43

You can change the center frequency without too much pain at the expense of unequal behavior left and right from the pot's 12 o'clock position.
I've built the bottom one with different values and it works great !

The real question is (and I had that question too - thanks POTL :D ) : why is the bottom layout more complex to achieve the same result ?
Any non-obvious advantage here ?
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Re: 2 Band Active EQ Comparison

Postby POTL » 07 Jun 2018, 14:29

I compared these 2 circuits (also I tried the variation of the first scheme with mid-range adjustment, I will immediately say that it works precisely and I do not recommend it for pure sound or pedals with low distortion level).
My impressions are the following, both circuits work very close (which is not surprising), but the second scheme gives a more natural sound, especially when adjusting the high frequencies.
I'm inclined to assume that the difference in filters is possible, unfortunately I do not understand how to calculate them, maybe with identical filtering level the sound will be identical, then the first circuit will be more practical, since it has less capacitor.

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bmxguitarsbmx (07 Jun 2018, 19:57)
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