Threads merged. Please do not start multiple threads on the same topic/question.Moving the bands has already been recommended twice. This is what is going to stop the controls from affecting the midrange. It works better too.
I have a small preamp I built as an exercise. It's in a small router chassis and has Elliot's tone controls, inverting gain stage (gain of -1.6), and a second order "peaking" high pass filter centered @ 16 Hz (provides a little 1-1.5 dB "bump" from 20-50 Hz). No muting, no relays, but it's very small, very robust (you could drive a car over it with the old router chassis), and sounds great even when mated with excellent power amp and speakers. It was built with almost all salvage and leftover parts.
I think we put more effort into simple tone controls than most manufacturers did. The only consumer grade tone controls I've ever actually liked are on my old Luxman receiver. Most bass controls add too much "boom" and some treble controls are downright harsh. We can do do much better.
Also, Rod Elliot's circuits always work, and are easy to modify and customize. His 36 dB/octave high pass filter is as simple as such a circuit can be, is well thought out to use multiples of the same value capacitors and resistors (you need a lot of them), and is the best "rumble" filter I've ever used. Once I put it in my main preamp I was surprised at just how much subsonic trash is in some modern digital sources (CD, MP3, etc). It made an enormous difference.
Yes, I've built several of those sub-sonic filters of his for various projects, they're a winner.
Elliot's high pass filter is the best I've seen for DIY. Many higher order filter circuits are cumbersome with odd value capacitors and resistors. With Elliot's circuit all the caps are the same value, so you just order 12-5% Wima MKP caps. Much simpler and you save a couple buck$ over ordering tow or three different value capacitors.
And here it is. https://sound-au.com/project99.htm Notice how all the values are strictly conventional. Many circuits I've seen use some cumbersome values.
And here it is. https://sound-au.com/project99.htm Notice how all the values are strictly conventional. Many circuits I've seen use some cumbersome values.
This circuit's a winner. https://sound-au.com/project97.htm Just replace the switch with a jumper and eliminate R16. Turnover frequencies can be changed by changing cap values. Very good "hi-fi" circuit and highly recommended for beginners. C1 = 100 nF and C2 = 470 pF for less intrusive tone controls. This is as simple as it gets and you will like it. Volume control and input cap can be placed right on the input. Then you have a complete turnkey circuit that you can put inside your power amplifier or other project.
Active filters can be really cumbersome. There is great virtue in designing something that works so well and is so easy to get parts for. There's no paralleling of capacitors, no combining resistors to obtain oddball values. It's very well parsed; as simple as possible but no simpler.
That's exactly why I've sometimes mentioned about simplicity of design, retaining purity of the signal.
The less manipulative components that the signal has to crawl through, the better.
You can't argue about that.
Every transistor has a junction, and it's own set of manipulation.
Every capacitor influences sonics as well.
And resistors....
While op amps are neat, they have to be chosen for the specific job.
