portable PA amplifier mod gone wrong!

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hello,

i recently bought a pretty good portable pa to use busking and to do cafe restaurant gigging. the product i am speaking of is a nano lucas 300 which i bought it for a really good price on a french version craigslists.
my plan from the beginning was to mod it to work on a lithium ion battery.
initially, i was thinking of connecting directly to the circuit board at 12v but, when i opened it up it i quickly realized that it was NOT running a simple 12v power supply and there was no transformer so naturally, i decided to just buy a dc to ac pure sine wave inverter.
the problem started when i had the fancy idea of taking the inverter out of its casing and install it directly into the amplifier in order to simplify transporting it. everything went fine, i made the rectangle cutouts for both the input dc and the ac output displays. it looked fantastic and admit i was quite inpressed with my drummel hacking. the surprised happened when i plugged in the battery and heard a loud hum that wasnt present when it was working on mains.
after, spending literally all night splicing in wires to extend the display wires, cutting out the holes to mount them and circuit board i was quite disappointed. the hum i figured out was some sort of ground noise but, i wasnt able to totally eliminate it.
bad part, i was upset and pissed tired from non stop hacking for 10 hours. i made the mistake of unplugging the speaking wire while the amp was still powered. the wire fell on the amplifier board and i heard a slight pop and that was "all she wrote"..........any suggestions as to how to get myself out of this mess would be greatly appreciated.
i am guessing that i toasted the amplifier IC but, i cant b sure until the ordered part comes in..........
 
Oh dear.
Service information is not released on this item, so without a schematic, we are a bit lost.
It is not really a buskers amplifier. 230Watts output is far too high with a very short battery life.
All I can suggest is replace the chip that controls the output and when you get it going, instead of converting DC to AC through an inverter to reduce it again to DC power for the amplifier, why not find out the DC requirements and use battery power for the amplifier if you must use an amplifier that is too powerful.
Most busking amplifiers are no more than 20Watts as that avoids nuisance levels of unwanted noise.
 
Dropping a bit of wire on an amplifier circuit board could result in pretty much anything.

You might've blown a fuse, or you might've shorted out something critical and taken out a long line of components.
Unless you're really really good at this stuff and have a schematic, I'd contact the manufacturer about repairs and/or replacement.

Chris
 
Buy a new amp. Serious.
Repairing yours, IF possible, will practically cost as much as a new one.

Go straight to a battery powered one, since that´s what you want and this is not.

As Jon Snell says, be realistic about what you can pull from a battery.

I commercially make battery powered amps for a living, my bestsellers are 40 or 60W RMS ones, fed from 1 or 2 12.6V 7AH batteries, smallest is 30W (biamplified 20+10W RMS) and largest is 100W RMS which is about the practical limit, so consider that when searching for a new one.
 
Yes, and don't forget to invest in a fuse on the +. An old (19v?) laptop power supply can be used for powering it from AC.
26V should be the max so if the li ion battery is 6 cells in series, it will be 6x4.2V = 25.2v charged = fine. Most 24V ebike batteries are 7 cells in series (29.4V fully charged) which is to much.
Some of these boards use 25V caps, don't give them more then 24V. The one I linked has 35V caps. The TPA3116 Thread.
 
I don't really get your question; these boards don't use AC. If the other parts need AC you will have to replace or bypass them as they will not run from DC.

The buck converts high voltage DC to lower voltage DC.
AC -> laptop AC/DC adapter -> board or
Ebike battery -> buck -> board
 
No problem as long it's clear to you. ;)

For mobile use you have an other challenge;
The mixer part of your system probably uses the AC as well, so that's unfortunate and you would need to replace it with a mixer that accepts DC voltage. There are not many of them, I have a beringer xenyx 302usb mixer which is powered by usb (5v DC) for small mobile usage and there are a few others.
 
yea, i avoided ac stuff for theses sorts of problems, i only used dc stuff. my update posts may be of help: #mytechproject

made a small start at writing documentation at Alexanders Log . idk if i will finish them, encourage me ;)

With all the Info given I think it's better to use the buck converter to connect the Berninger xr12 mixing board too!.... That dam sine wave inverter is dam big and heavy!😁
 
your mixer may well use Duel +/- DC inside. I’m personally having trouble finding good, low noise dc-dc converters for duel dc. i got one from digikey but I hear a ton of noise using it to power a tone board. :( other +/- dc-dc converters i had for it where silent -audible noise wise-, but got fried due to capacitive load :( i guess. Yurrgh. its not easy!
 
Instead of your mixxer, What about using a laptop with a USB DAC? running GNU/Linux using JACK for audio connections and filters. with a remote desktop or cleaver remote X or gui or ctrl over ssh to control your levels and filters on the computer running jack?

to get an idea of jack, have a look at screen shots in:
gnu/linux audio ready-to-go distributions: DistroWatch.com: Put the fun back into computing. Use Linux, BSD.

follow the links, for info tail: Introduction to music creation in Linux [Linux-Sound]

this idea is something ive been wondering about for a while but not needed to try and setup it up. cus i don’t do any mixing really.
 
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