It should be OK as it is. The definitive test would be testing with squarewaves and using a scope though. Given the high resistor values it should be fine though. You shouldn't need R8 as the opamp sees no real capacitive loading apart from layout and trace strays.
And no biasing to class A 🙂
And no biasing to class A 🙂
FET input stages are much more immune to RF than bjt. Unless you are on top of a transmitter then there shouldn't be a problem.
i built two versions of this tilt equaliser. one the original schematic presented in the beginning and the other one with a fet buffer. but....... on the second one the buffer is non inverting and the tilt section is inverting which leads to 180 degrees difference for the output signal. is this 180 degrees phase difference audible on speaker??
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The phase shift and its audibility is debateable depending on the music and how it was recorded.
It is easy to try, just swap the speaker leads over on both speakers (plus to minus) and that corrects the 180 degree error.
It is easy to try, just swap the speaker leads over on both speakers (plus to minus) and that corrects the 180 degree error.
My understanding is that some people can detect phase inversion on some music. On the other hand, I have also heard that radio broadcast chains (and possibly some recording studios too?) make no effort to maintain phase polarity so you get random polarity anyway.
I guess that means that if you are sensitive to phase you need to add a switchable inversion stage to correct those sources which are wrong. If you are not sensitive then you don't need to worry.
I guess that means that if you are sensitive to phase you need to add a switchable inversion stage to correct those sources which are wrong. If you are not sensitive then you don't need to worry.
Hi, for a complete parametrization of the tilt filter see my post:
http://www.diyaudio.com/forums/anal...qualizer-filter.html?highlight=tilt+equalizer
For limiting the bandwide the best thing is to put a lower C1 and a cap across R4 in the buffer. Francesco Balena
what changes do i have to make in order the tilt equaliser have non inverting output? can a tilt equaliser be build with an opamp in non inverting configuration and how?
Like all active tone controls an inverting stage is needed. Replace your discrete front end with an inverting opamp stage. You would also get the benefit of a lower output impedance with an opamp making the tilt stage response less affected by interaction with the higher impedance discrete buffer.
oops I found hi ypjc . you can also have a look here. Designing A Pocket Equalizer For Headphone Listening | HeadWize it s about at the middle of the page.
I worked on a mixing board just underneath a tv transmitter.
I up graded the bipolar input with fets.
that worked fine even under the transmitter.
Here is a version that I built some time ago. It works well.
With my formulas (see http://www.diyaudio.com/forums/analog-line-level/228632-tilt-equalizer-filter.html)
the displayed circuit have the following parameters:
Pivot frequency Fp = 898 Hz
Max Low freq boost ML= near 6 dB
Max Hi freq boost MH=near 6 dB
With my inverse parametric formulas it's easy to schift Fp where you wont ( ex. 440Hz) and to choise ML and MH. In the following figure there are 3 different Fp,
Remember that ML and MH can be different !!! Assymmetric response is possible. See the following FIG.
If somebody want to tune a tilt filter, tell me.
Francesco Balena
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