6 Band EQ formula?

[caspercody]

Yes, i do have a 7 band eq, Danelectro Fish and chips.

Using the calculator link, i came up with the cap values to get 160hz, and 600hz. I do not know much about the Q filter, but changing these same values from C1 to C2 really changes the Q. See attached:

 

[Chuck D. Bones]

Are you able to obtain the desired tone using the Danelectro? I'd think that a 7-band EQ should be able to do a respectable job mimicking a 4-band EQ.

The impedance of the filter at resonance sets the gain at the center freq. With the gyrator, the impedance at resonance is equal to R2. With the MP1, the impedance at resonance is R150 thru R153. But the circuits are different so you don't use the same resistances. This project is a bit of a rabbit hole.

 

[caspercody]

Okay, I built the 6 band EQ, but only used 4 of the bands. I made it with the 4 frequencies as the MP1 just changing (4) caps per the calculator.
And it works, but the volume drops a lot. I am guessing i could increase resistors R3, and or R7 to increase the volume. Does that sound correct to try? Maybe even a pot on one of the resistors? Any thoughts on resistance value to use?

Here are my changes made:

C5 = 560N
C6 = 150N
C9 = 120N
C10 = 56N

POT5, and POT3 and their circuits not used.

 

[Chuck D. Bones]

When all of the pots are centered, does the volume drop?

 

[caspercody]

Yes

 

[Chuck D. Bones]

Then it's built wrong. When the pots are centered, the gain should be unity no matter what R & C values you use in the gyrators.

 

[Chuck D. Bones]

Did you install R13 & R17? If not, then you should to keep IC2 happy.

 

[caspercody]

Got it working, stupid me. Pin 1 from the pots was not soldered.

Now, I was thinking of adding this EQ to the end of the new Victory preamp circuit for their V1 pedals. I thin their new design sounds very good. The Kraken, Sheriff, and Jack circuits are very similar. I attached a copy of the schematic where i show the different values for all (3) pedals.

If I were to hook up my (4) band EQ at Victory part number C4, and output of (4) band EQ to Victory part number R10, would this work? Obviously eliminating the Victory EQ portion. Do I even need Victory R10 and on parts?

 

[JTEX]

Funny bit of trivia. I work with a certain fellow who, a long, long time ago, dropped out of university in disgust due to, among other things, having been told by one of his professors that the gyrator-based parametric EQ he was designing couldn't possibly work - while he already had it working.

 

[caspercody]

I have been trying to re-create the ADA MP1 sound. I made a tube version, with the buffer and OP amp distortion going into the tube section. It works, but I was not able to get the EQ section working great. I decided to try to make a simpler version of the ADA MP1 EQ section. I got it to work.

Now I am curious about connecting it to a good OP amp pre amp circuit to see with using the ADA MP1 EQ section how close I can get to the ADA MP1 sound. Answer a question i have of how much does the actual sound of an amp come from the circuit, or the EQ section?

There is a Youtube video where a Nashville guitarist tries this and makes his own pedal box with different tone stacks connected to the same distortion section to sound like either a Marshall, Vox, or Fender. And places the tone stack in different stages of the circuit.

I just want to try this, since I have the EQ as a separate circuit i can insert into my Victory pedal.