I'm going to be making 2 equalizers. The first one is a bit more simple than the second. I'm definitely going to get PCBs made up upon completion, and I hope to test and revise these projects enough to make them desirable.
here's the "simple" first project.
1. separate pcbs for each band, but they'll link together.
so you can configure and have as many (or as little) bands as you want,
2. 1octave Q control,
3. Frequency control.
so I would need a separate PCB for the I/O transformers, correct? so it could look like this:
power > input transformer (pcb1) > "X" amount of bands (pcb 2,3,4 etc.) > output transformer (pcb1 again)
Here's what I want in the end:
- still analog despite some digital controls
- Q control, one octave
- motorized pots for presets
(I'm talking to a friend knows microprocessors about this)
- separate boards for each band, individual I/O transformers
- internal summing board at the end of the chain.
- DIY friendly - ability to have a chassis and as many bands as wanted.
so I'm probably crazy because I have yet to complete a DIY pcb project, but I don't care so much about that. I am an obsessive sort of person and will not quit until I have a perfect (to my ears) EQ. I honestly spent 8 hours trying to solder an xlr cable the first time I tried because I wrote directions down wrong. I am serious about designing these EQs and would like as much help as people are wiling to give me. I'm a fast learner and really want to design things that give people a chance to own decent gear.
So, as far as prototyping equipment goes... what should I get and what should I stick the most money into? I have a good soldering iron, caliper, and multimeter.
I'm guessing I need an oscilloscope, will those cheap USB style ones serve me well or do I really need to drop a ton of money on one? I actually found a DIY one for ten bucks:
http://www.geocities.com/pcscope/
thanks for all the help/advice in advance and try not to laugh to much at my ambition vs. experience ratio...
~ Jeffrey James
here's the "simple" first project.
1. separate pcbs for each band, but they'll link together.
so you can configure and have as many (or as little) bands as you want,
2. 1octave Q control,
3. Frequency control.
so I would need a separate PCB for the I/O transformers, correct? so it could look like this:
power > input transformer (pcb1) > "X" amount of bands (pcb 2,3,4 etc.) > output transformer (pcb1 again)
Here's what I want in the end:
- still analog despite some digital controls
- Q control, one octave
- motorized pots for presets
(I'm talking to a friend knows microprocessors about this)
- separate boards for each band, individual I/O transformers
- internal summing board at the end of the chain.
- DIY friendly - ability to have a chassis and as many bands as wanted.
so I'm probably crazy because I have yet to complete a DIY pcb project, but I don't care so much about that. I am an obsessive sort of person and will not quit until I have a perfect (to my ears) EQ. I honestly spent 8 hours trying to solder an xlr cable the first time I tried because I wrote directions down wrong. I am serious about designing these EQs and would like as much help as people are wiling to give me. I'm a fast learner and really want to design things that give people a chance to own decent gear.
So, as far as prototyping equipment goes... what should I get and what should I stick the most money into? I have a good soldering iron, caliper, and multimeter.
I'm guessing I need an oscilloscope, will those cheap USB style ones serve me well or do I really need to drop a ton of money on one? I actually found a DIY one for ten bucks:
http://www.geocities.com/pcscope/
thanks for all the help/advice in advance and try not to laugh to much at my ambition vs. experience ratio...
~ Jeffrey James
If you use a state-variable filter, frequency adjustment requires a 2-section pot, and those sections should track accurately.
Rane has schematics on their website. IIRC they used VCAs in a parametric EQ, since they would track perfectly and it tunes the filter the same way only different.
Your best value for an oscilloscope is PC sound card or USB sound device. No instrument you could afford would have better resolution at audio frequencies.
Rane has schematics on their website. IIRC they used VCAs in a parametric EQ, since they would track perfectly and it tunes the filter the same way only different.
Your best value for an oscilloscope is PC sound card or USB sound device. No instrument you could afford would have better resolution at audio frequencies.
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