NickApparently
Member
- Joined
- Aug 5, 2018
- Messages
- 12
Hi All!
As I'm growing more intrest to build a parametric EQ and compared different designs, I couldn't find the answers to some questions. Mainly, why is which topology used? And how does a switchable bell/shelf work?
Most (all?) designs I've found do something like this:
https://www.dropbox.com/s/ssmbwdla6wfz8hk/Schermafdruk%202018-08-09%2020.45.12.png?dl=0
Except the populair SSL 4000 - 242EQ does a different trick:
https://www.dropbox.com/s/44luiw2qh6rot1k/Schermafdruk%202018-08-09%2020.58.22.png?dl=0
Could anyone explain what the difference between those two topologies is?
Next to that;
Most filters use the same cutoff frequencies for the high-pass and the low-pass, IE: the capacitor values are the same. Though, when I searched for a switchable bell/shelf EQ I mostly find SVF's with different cutoff frequencies. For example this one:
https://groupdiy.com/index.php?topic=62157.msg812575#msg812575
Could anyone explain why the capacitors have a different value and why the schematic would result in a switchable bell/shelf EQ?
Thanks
PS: How can I insert an image?
As I'm growing more intrest to build a parametric EQ and compared different designs, I couldn't find the answers to some questions. Mainly, why is which topology used? And how does a switchable bell/shelf work?
Most (all?) designs I've found do something like this:
https://www.dropbox.com/s/ssmbwdla6wfz8hk/Schermafdruk%202018-08-09%2020.45.12.png?dl=0
Except the populair SSL 4000 - 242EQ does a different trick:
https://www.dropbox.com/s/44luiw2qh6rot1k/Schermafdruk%202018-08-09%2020.58.22.png?dl=0
Could anyone explain what the difference between those two topologies is?
Next to that;
Most filters use the same cutoff frequencies for the high-pass and the low-pass, IE: the capacitor values are the same. Though, when I searched for a switchable bell/shelf EQ I mostly find SVF's with different cutoff frequencies. For example this one:
https://groupdiy.com/index.php?topic=62157.msg812575#msg812575
Could anyone explain why the capacitors have a different value and why the schematic would result in a switchable bell/shelf EQ?
Thanks
PS: How can I insert an image?