spaceludwig
Well-known member
- Joined
- Jul 14, 2011
- Messages
- 186
I need some help and advice modifying the bare-bones EQ (high, mid, low at 100, 1K & 10K respectively) on the console I finished upgrading (recapped, upgraded opamps, changed input transformers)
Schematic (rotated for ease) of the EQ section below:
If I am not mistaken, I can change the value of the caps tied to the wiper of the 50K pots to change the frequency, correct? My problem is the values I get when I calculate the frequency the components already there are supposed to give me they do not jive with their supposed corner frequencies i.e.,
These figure are off by a factor of 1.5, more than 2x for the low frequency. I am obviously making some very basic mistake.
So, before I figure out what values I need and how I will physically integrate this into the existing circuit I was hoping some of the knowledgeable posters could explain where I am going wrong in my calculations, what I am overlooking, forgetting, don't know, etc to lead me to the correct figures. I am happy to do this step by step rather than rushing through the whole procedure.
ultimately, I would just like to add a few values to each band that I can select with some kind of switch, probably rotary.
Thank you all in advance, looking forward to reading your comments/feedback.
Cheers
Schematic (rotated for ease) of the EQ section below:
![Eq%20Circuit.PNG](https://proxy.imagearchive.com/a4b/a4be43fdab134d9ffa70f78af792e427.png)
If I am not mistaken, I can change the value of the caps tied to the wiper of the 50K pots to change the frequency, correct? My problem is the values I get when I calculate the frequency the components already there are supposed to give me they do not jive with their supposed corner frequencies i.e.,
- high: 470R &0.022uF =15.4kHz
- Mid: 0.18H & 0.056uF = 1.6 KHz
- Low: 1.2H & 10uF =46Hz
These figure are off by a factor of 1.5, more than 2x for the low frequency. I am obviously making some very basic mistake.
So, before I figure out what values I need and how I will physically integrate this into the existing circuit I was hoping some of the knowledgeable posters could explain where I am going wrong in my calculations, what I am overlooking, forgetting, don't know, etc to lead me to the correct figures. I am happy to do this step by step rather than rushing through the whole procedure.
ultimately, I would just like to add a few values to each band that I can select with some kind of switch, probably rotary.
Thank you all in advance, looking forward to reading your comments/feedback.
Cheers