I’ve made good progress this week like getting the pre-amplifier working which I will detail in a future post. Today I want to discuss the constraints I’m placing on the project with the intention of making it as close as possible to what I want.
- Amplifier circuit must allow for overdrive
- While, it is not uncommon to keep the signal from an electric guitar clean; most players (especially in rock and related genres) will overdrive their amplifier at least a little bit to add some fuzz to the sound. Overdriving the circuit a lot results in distortion. Since the signal and sound production is entirely contained in the guitar I do not expect to be hooking up any effects pedals meaning any overdrive will have to come from the amplifier itself. Luckily the preamp circuit is designed to provide a bit of overdrive and through testing I have seen that this does in fact occur at high volumes.
- Power amplifier must drive the speaker at listenable levels
- A cursory google search showed that a rock concert is often around the 120 dB mark. This is clearly an unrealistic goal so I am shooting for something closer to conversation level or a hair dryer. This places my goal between 60 and 80 dB. I believe this to be reasonable but will need to determine how to evaluate the results.
- No exposed electronics
- While I want this guitar to look “road worn” I have begun to shy away from the idea of having it look slapped together with a mismatch of parts. I want it now to look like a polished product that has been used extensively. This means that any electronics or purposeful holes in the guitar must be hidden or covered.
- Speaker must have volume control knob
- The power amplifier board I got from sparkfun leaves a potentiometer to control volume as optional. For me this is not optional. Controlling the volume will be essential to making this project actually be useful. There are very few instances in the world of speakers without volume controls and I have no intentions of my project being one of those.
- Battery powered
- This one is not a hard and fast constraint. Since I have discovered that the max voltage necessary to power this project is 9 volts it should be possible to power with a battery. My hesitation lies in my lack of knowledge about the amperage draw. This would be a pretty pointless battery operated object if the battery only lasts a few minutes (although a lot of small drone manufacturers seem to disagree)
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It definitely looks like you’re getting closer to honing in on your product here. I like the aesthetic of “road worn” guitars and think that it will look more put-together than your original aesthetic direction. I recommend sanding a few parts of the guitar body down to the primer, and then playing the heck out of the neck to get those frets worn down. You also get to choose what knobs to put on… maybe choosing some mismatched knobs like guitars that have lost theirs through years of rock shows?
Nice work making progress on the circuits end of things!
Ethan, it sounds like you’re off to a great start by addressing many of your goals for the project and how they are limiting factors. Like you said about my project, it is easier to complete your goals once you’ve set them. I’m excited to see how this project develops.