Okay, so I have a rescue guitar from the 80's that actually sounds really good with fuzz or high gain, and the novelty of the instrument is that it has a speaker built in. After replacing all the sub-par components, including the speaker, I find that the only thing left to address was the fact that the 9volt battery inside is drained super quickly.
I have some soldering experience when it comes to electronics, but I am not an expert by any means. I was hoping that someone here might have an idea for some way to negate the use of a 9volt, either with an alternative (less expensive) battery set up or preferably by stepping down the voltage of a 12v transformer (however one might manage to do that). At first I thought USB stepped up to 9v might be a solution but after some research, that seems to be a pain in the ass to efficiently accomplish without just buying a converter. Any ideas?
>>985468
You might not need all 9V to begin with; make sure there's not a vintage linear voltage regulator inline as well.
step up would require only a buck-boost converter, depending on the power draw this might be a single chip solution or you might have to make one. They are not as complex or hard to put together as you might think.
If you really want the nigger-rigged less expensive setup, use 6x AAs (or AAAs). 9V batteries are just 6x AAAAs in a hard case anyway (if you don't believe me, take one apart with pliers)
>>985480
sorry forgot the image
Just get another 9v battery terminal and wire it to a wall wart. Just make sure you wire the terminal you're adding "backwards" so the DC comes in with proper polarity.
>>985481
Haha that's crazy. I was watching a tool review channel on youtube the other day and the guy doing the review was taking apart the entire tool, showing the motor, gears, etc, and when he took apart the battery case it was literally just 6 D batteries.
>>985468
https://www.youtube.com/watch?v=VWi0b5LQ6Jg
>>985468
You can buy a dc dc converter, that would be most efficient since they usually don't have a lot of energy loss, you can also use a voltage regulator ic, like the lm317T and with that you can set up any voltage you want fairly easy.
The circuit of the lm317T is really simple aswell.
>>985468
>... Any ideas?
Numbered for arguing convenience:
1. If it runs off a 9v battery, then it's not drawing much current at all since those batteries just can't put out very much.
There is three options here:
2. run it off an external battery tray that holds 9 volts worth of D-size batteries (that is 6 D-size batteries in series). No converter is needed for this, just the battery tray and the wiring/connection jack.
3. run it off a 9v dc wall-wart power supply.
4. run it off a 12v dc power supply and use a bucking converter to change the 12v down to 9v.
Now then:
5. You can find 9v wall-wart power supplies, but they may introduce a lot of line noise that the battery did not have.
6. 9v power supplies are not real common. 12v ones are way more common, and cheaper.
7. Ideally you would want to get a switching power supply, as it will put out a smoother voltage.
8. If you use the bucking converter, that will smooth out the power of a cheap power supply. The converter is small enough to fit inside the compartment where the 9v battery goes, just the power cord would hang out.
Finally:
9. The tiny amount of current from the battery MAY affect how the guitar sounds, and you may lose that effect if you run it off a larger power supply.
10. If you want to limit the current also, that would involve a bit more work--but that can be added on later and placed inside the guitar. Look for "LM317 current regulator" info; it needs only 2 or 3 parts.
https://en.wikipedia.org/wiki/LM317
why not ditch the silly onboard system and use a real amp?
I stuck a 7809 a radio of mine with a 9 volt usage.
>>985468
You might want to consider swapping out the amp. Back in the '80s, the state of the art was a class AB amp. Not very efficient. Switch to a modern switching audio amp and your battery life will go up. As a side benefit, you will get a chance to select something that uses 'better' batteries.
>>985661
Actually, it's not true that those batteries put out a tiny ammount of current, I once tried measuring the current a 9v battery could put out, and was supprised that it actually gave me 13 amps
can't you just hook it up to a 9V power supply?
>>985661
Never use a switching power supply for audio equipment. It will introduce A LOT of high frequency noise.
>>985661
>9v power supplies are not real common
They're extremely common in music stores, effects pedals run off them.
>>985468
That guitar runs off two 9volts, so you need 18v. And maybe a center tap
>>986045
Actually it will run off just one 9volt, there's just space for two, probably for convenience since it drains so quickly
>>986060
if it will run off one but takes two, they are wired in parallel
You are right that this may just be for convenience, but it may also be a high or unsafe amount of current draw from just one
>>985934
Thats not what they are designed for though. All batteries have an optimal current they can supply and still get good mAh out. 9v can last a very long time as long as you only draw small amounts of current from them. AAs are much more suited for high current applications.
>>985468
One question I have, that I feel hasn't been raised in the thread.
Do you want to keep the guitar's mobility, sure you can plug it in a power supply or usb, but would you sacrifice too much of the guitar's novelty, because at that point you could just use a regular setup and not worry about the batteries.
That guitar is sick though, I have to say.
>>985585
thats horrifying.
whats the output, 9v 5ma ?
I'm not any kind of expert, but I'd want to replace it with a more efficient battery source. Probably a couple of 18650s.
