1. All-in-One Guitar Amplifier
Paul Shumay
Bruce Ankenbrandt
Sarah Echler
Brynn Schultz
Instructor
Dr. Gursel Serpen
Advisor
Dr. Richard Molyet

2. Introduction Paul Shumay - Team Leader Bruce Ankenbrandt Sarah Echler
Overdrive and Reverb Effect Design
Bruce Ankenbrandt
Fuzz Effect Design, Lead Integrator
Sarah Echler
Microcontroller Programming
Brynn Schultz
Power Supply Design

3. Background Information
What is the role of guitar effects devices?
most commercial amplifiers have effects built in
some manufacturers build single effect devices
usually has foot controls
Common features:
Applies a single effect to the guitar signal
Multiple power sources are required for multiple effects
Requires time for setup and disassembly

4. The All-in-One Guitar Effects Box
Design contains multiple devices
Amplifier was omitted from the design
Requires a single power source
Device is portable
Utilizes an LCD display for the user interface
Integrated footswitch for control while playing

5. Functional Overview

6. Power Supply 120v transformer Bridge rectifier
220uf Smoothing capacitors
+/-9 output voltage
The power supply is made up of 3 parts. The transformer which we chose to be 120v because it would get us close to what we need for the effect circuits which is +/-9v.
The bridge rectifier is used to convert the ac voltage signal into the dc voltage signal. The DC supplied by the rectifier would consist of of sine waves with the voltage fluctuating. This would be make the power supply useless for the dc circuits. The circuits would not function due to the fact the power would be removed every half cycle. To smooth this output signal smoothing capacitors were added. Over specifying the size of the capacitor needed would add unnecessary cost and weight and under specifying would lead to poor performance quality. With calculations we discovered that 220uf would give us the results we needed. This supplies power to the effect circuitry.

7. Power Supply

8. Microcontroller Four basic components Arduino Micro
Potentiometer circuit
Control Relays
LCD screen

9. Arduino Micro Controls all non-signal circuitry
Potentiometer/Voltage divider circuit
Control relays
LCD Screen
Uses a footswitch to control the inputs/outputs
Operate on 9V
Contains 5V regulator

10. Potentiometer Circuit
Potentiometers monitor the modification level of the signal
Voltage divider is used to monitor this modification
Selectable by the footswitch

11. Control Relays Signal flows through effect Uses 5V or 0V for Logic
Activates one relay at a time to pass the signal through
Clean (Unmodified)
Fuzz
OverDrive
Reverb

12. LCD Screen System Status Displays Potentiometer Position
Which effect is selected
How much distortion applied
Potentiometer Position
Uses voltage divider to display a percentage

13. Fuzz Effect A Type of Distortion similar to clipping
Uses an asymmetric clipping
Uses a BJT saturation and cutoff modes
Controlled by gain and capacitor filtering

14. Fuzz Waveform

15. Fuzz Effect

16. Overdrive Effect What is Overdrive? Different Types of Clipping
Hard Clipping
Soft Clipping

17. Overdrive Effect
Puts circuit into overdrive to force the Op Amp to clip the guitar signal
Operates based on underpowering a single LF356 Op Amp
Potentiometer in feedback loop to give user control over the severity of clipping

18. Overdrive Effect
Overdrive Effect

19. Overdrive Effect

20. Reverb Effect
What is Reverb?
Different simulated environments

21. Reverb Effect
Circuit needs to add delayed copies of the signal before output
Can be created either digitally or with a reverb tank
Amplifiers connected at the input and output of the reverb tank

22. Reverb Effect

23. Reverb Effect

24. Summary Three unique effects in one device
One power supply for the device
Portable and compact
Footswitch for easy control while playing
LCD display for readability
Saves user cost of buying multiple devices

25. Progress Report Completed: In progress: To be completed:
All circuits prototyped
Testing is near completion on individual circuits
In progress:
Arduino programming
Enclosure construction
To be completed:
Acceptance testing

26. Questions?