Mic, Line, EQ... Preamps

Schematic for preamplifier for sabwufer

Hi
I need a diagram and PCB for an active filter for the subwoofer amplifier: "Quasi amplifier for beginners" (of APEX Audio).
Regulated frequency of 40...120 Hz with a slope of 12...18dB.
This preamplifier that can directly to be connected to output to my stereo amplifier.

Thanks for your help
 
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Hi apex. I have made apex ml3 pcb. This is the result. Quality is good enough. But i had a little hum, but when i touched the casing of my amp, hum was disappear. Can you give me any advice for it. How to wiring apex ml3 correctly? I just used simple regulated power supply. Thank you very much.
 

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Hi apex. I have made apex ml3 pcb. This is the result. Quality is good enough. But i had a little hum, but when i touched the casing of my amp, hum was disappear. Can you give me any advice for it. How to wiring apex ml3 correctly? I just used simple regulated power supply. Thank you very much.

You must grounded your case (gnd from regulated psu connect to amp case)
 
apex,
please help how to put balance pot ,
i will use ML3 as multiple input maybe 4 or up ML3 and feed it to MX1,
i just hope your help of adding a balance pot to assign left/right to MX1 as master and ML3 as multiple input,
hope you help
 

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Mixer

Dear Mile...
I was make a new layout of Your tone control with add a XLR con for mic input...I got a plan to make 4 ch mixer with 2 mono input and 1 stereo input but I don't know how to add effect and another block like master and balanced output...
Can You help me to make my simple mixer??

Regards
 

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Portable version

Mile,
Thanks for this thread!
I'm looking at this for use as a belt pack unit for a friend who plays accordion.
Two channels with all controls. Balanced input and output.

Is there a way to get this functionality with only a 9volt battery? I'm also curious how long it will work if I use two 9 volts?

Many thanks for sharing your knowledge with us.:worship:

Chris