request help for mini amp project

[jclark2021]

I'm trying to build an amp small enough to attach to my acoustic guitar. Here's what I'm thinking: I'd like to use about a 3" speaker and enclosure for the amp and assembly. Then i'd like to figure out how to make a small switch to turn on a delay effect. I reckon i'm really probably getting ahead of myself and over-extending my very meager knowledge of what i'm doing, but i'd like to get thoughts on how or if it might work. I'm not really looking for specific details or anything. thanks in advance.

[jackand08]

It depends on how much wattage you want, more wattage is more power but also means that you may need a higher power (mains) supply instead of keeping it safe using a battery. Also, if the speaker you are using is not very efficient at converting this power into sound waves, power will be wasted and it will not sound louder. Basically, a 1 watt amplifier with an efficient speaker can be louder than a 3 watt amp with an inefficient speaker.

The main question to determine how much power you need is what the amp is going to be used for. Obviously with a 3" speaker you can hardly gig with it so I'm assuming that what you want is a small practice amp of some kind. The best way of doing this is probably to use an IC (integrated circuit) to do the amplification. The first IC that springs to mind for me is the LM386. This has an output power of around 1 watt and can be battery powered so it would be safe to use and build. I'm fairly certain that there are kits using this IC out there so its best having a search round to see what you can find.

With regards to a switch to route the signal to an effect, is the effect an external pedal or are you planning to include the effect in the enclosure?

Also, you may need a preamplifier to boost the signal coming out of your acoustic guitar as the gain of the main amplifier may not be high enough. Again, there are plenty of circuits out there for you to have a look at, probably along with some kits that do the same thing.

[VictoriaGuy]

What are you trying to accomplish?
Do you want to physically attach the amp to the guitar, or connect with a cable?
Does your acoustic guitar have a pickup installed already?
You are going to need substantial battery power to produce enough audio to compete with a decent steel string acoustic, BTW.

[AndrewT]

An acoustic guitar has an acoustic output.
Why do you need a poor copy of that and not at a higher volume?

[jclark2021]

The point is to change the nuance of the guitar using the amp to add a little spice to the sound. So what i'd hopefully end up with is the acoustic sound layered with the small amp with some distortion. And it would be neat to have the delay right there in the enclosure; how feasible or expedient that would be, I don't know. I'm just trying to bounce ideas.

I'd looked into some LM386 chip builds, but my skills at reading the schematics are so poor what I ended up with wouldn't even make noise. I understand the basics, but all the schematics i see are all so complicated i can't understand them. and they all look different to me. So maybe if someone could direct me to a good place to learn to read them, that could be helpful too. Thanks in reply and advance.

[maurycy]

How you are going to connect the amp to the guitar? Is your guitar acoustic-electric or you are going to add pickups?

Hitachi HA13118 will give you about 18W mono with gain of about 55dB. I am building one for my electric guitar.

And it comes as a kit:
Kit 105 18W amplifier

[LAJ]

I'd go with a 6" speaker and an LM386 chip. The larger speaker moves more air and thus is louder.

[jclark2021]

@maurycy,

what do you think about working in a delay component into that?

[maurycy]

I am afraid that I can't help you with delay. Do not have enough skills to modify the circuit. Maybe somebody else can provide an update to the circuit.

[jclark2021]

Is there a better place to go with questions of that nature? and do you know of a good place or good way to learn how to read the schematics that come with the kits?