1. 6 Channel Mixer Jean G. Occeus Jr.New England Institute of Technology EET 258

2. Device Description This device is a 6 channel mixer designed to combine three line inputs with three microphone inputs, and send all the signals to one output. A 6 channel mixer is used in audio production to combine various wave forms (guitar, drums, vocals, etc.) and create an overall mix of the audio for recording and/or live performances.

3. 2 Current Models Mackie DFX6- 6 channel mixer with effects +48 v Phantom power for microphone connections inputs and outputs Slider knobs and LED monitoring On board 32 bit digital effects (Reverb, Flange, etc.) High and Low frequency equalization Soundcraft EPM6 6-Channel Mixer 2 Auxiliary buses XLR and microphone or line connections RCA jacks 3 band and 2 band equalization Led monitoring 1 headphone output

4. 6 Channel Mixer 3 Mic Inputs/ 3 Line Inputs Block Diagram 6 Volume Controls 3 Microphone Amplifiers VOL 1 Main Mix AmplifierMIC IN 1 1 Main Mix Volume Control VOL 1 Main OutputMIC IN 2 VOLMIC IN 3 VOLLINE IN 1 VOL VOLLINE IN 2 OUTPUT VOLLINE IN 3

5. 6 Channel MixerSchematic

6. Block / Schematic Reference Section 6 circles on the block diagram are used to identify the inputs and outputs on the schematic. Microphone inputs on the block diagram are associated with a 10 microfarad capacitor and a 1 kilo-ohm resistor feeding the amplifier section on the schematic. #1-#3 triangles on the block diagram are associated with the LM741 microphone amplifiers on the schematic. VOL rectangles on the block diagram are associated with the 10 Kilo-ohm volume control potentiometers on the schematic. #4 triangle on the block diagram are associated with the Master Mix amplifier on the schematic. Dual 9V power supplies are used on the schematic, but are not referred to on the block diagram.

7. Simulation and Results 4 channel oscilloscope Channel A Sine Wave Channel B Triangle Wave

8. Simulation and Results 4 channel oscilloscope Channel A Sine Wave Channel B Triangle Wave

9. Simulation and Results Bode Plotter Output = Band-pass Waveform Frequency Cutoff= 25.009 Hz

10. Simulation and Results Bode Plotter Output= Band-pass Waveform Frequency cutoff @ 141.8 Khz

11. Simulation and Results Oscilloscope Sine wave showing volume control and clipping

12. Simulation and Results Oscilloscope mixer output Sine Wave showing peak to peak voltages

13. Simulation and Results Multisim Simulation Schematic 1 Function Generator producing a 1 Khz Sine wave 1 Function Generator producing a 1Khz Triangle wave 1 Oscilloscope monitoring the amplifier outputs 1 Oscilloscope monitoring the Master Mix amplifier output.

14. PCB Layout The 6 channel mixing board was laid out to make the inputs and outputs accessible. The design is intended to resemble the layout of the schematic.

15. PCB Layout 3D model of the overall layout of the 6 channel mixing board.

16. Manufactured Printed Circuit Board

17. Completed Printed Circuit Board

18. Printed CircuitBoard Pricing Board Price: 1=$ 1000=$

19. Pricing of Mixer1. 1 mixer would cost $325.00 for one day shipping.2. 1000 mixers would cost $4.61 each for one day shipping.

20. 6 Channel Mixer Video 1 Microphone connected to input channel 1. 1 radio connected to input channel 2. The out of the mixer is connected to the LM386 amplifier feeding an 8 ohm speaker. Voice and Music are mixed together at the output.

21. Retrospective The 6 channel mixing board was designed to mix 6inputs through one output using an operational amplifier. Theproblem with this design is its inability to adjust the volume ofthe mixers output. Future modification to the printed circuit board wouldincluding volume control for the output, and a LED display forvisual monitoring of the overall signal.

22. Closing Slide In closing, I would like tothank New England Instituteof Technology for educatingme, and helping me see theimportance of engineering inthe everyday world. A special thanks toprofessor Recorvitz for hispatience and dedication to theelectronics engineeringprogram here at NEIT. Albert Einsteins quote:Education is what remainsafter one has forgotteneverything he has learned inschool.