Help to build up a tube equalizer

ctechdx · Mar 7, 2020

Hello folks,

I want to build this tube equalizer and need some help to do it right. *Schematics attached

I´m trying to simulate a stereo version in multisim. The simulation runs without errors, but I cannot measure the equalizer properly. I´m not sure how to do this, but I suppose with an oscilloscope I can see an equalizer boost in 1k tone. But in practice, I get only one dB of gain change when I move the pot for 1k frequency eq.

Please could someone help to understand what´s wrong? I´m studying a lot but still a newbie on this. I did check everything and don´t get what is wrong. Maybe I´m doing the measures wrong.

Here a pic of my project in multisim:

https://ibb.co/6Nnf4kt

*the image doesn´t show the entire simulation, it couldn´t fit the screen, but it´s all the same with only capacitor change. I´m trying to simulate a 6 bands stereo version of this eq.

Thanks!

echoplex · Mar 10, 2020

Sorry, I can't really help you but this EQ looks very interesting indeed.
May I asked which book this scan is from?
Would love to test it actually..

fazer · Mar 10, 2020

Glass audio was a magazine in the 90’s. About building and understanding tube circuits. I have some of those mags still and there is a website where you can buy issues I believe.

ctechdx · Mar 10, 2020

echoplex said:
Sorry, I can't really help you but this EQ looks very interesting indeed.
May I asked which book this scan is from?
Would love to test it actually..

Actually I don´t know. A friend of other forum share this with me. Seems to be a quite interesting project, but I still cannot make it work in a simulator. I don´t have much experience, then I want to understand and make it work in the simulator first. Hope someone can help. I don´t know what I´m doing wrong.

Michael Tibes · Mar 12, 2020

Maybe if you post your simulator file someone could help?

Some people here renamed the file to .jpg, so that they could attach it to the post.

Michael