Schematics Help Needed

[George90]

Hi, I'm dealing buying a Fisher Loudbox Mini and need help make a mod bypassing its internal tranformer and give power to it directly from a car battery for busking, I've done this on a cube street ex but that has already the battery powering option so it was easy to do. I will upload the fishman schematics and a photo of its tranformer. Also could anyone tell me for sure guided from the schematics if the board uses ~13-14 V ? Thank's for helping..fismnan schematic

 

[Evertide]

The power-supply is using + and - 33 Volt for the amp , than lower it to + and - 14 Volt and also +3,3 Volt.

So you will need 6 car-batteries with the amp , or 2 without amp...

 

[Gold]

Why not get a 12vdc to line voltage inverter? Seems much easier.

 

[pucho812]

Why not get a 12vdc to line voltage inverter? Seems much easier.

The simple options are often overlooked.
I agree with the inverter. Inverter + battery and boom, bobs your uncle.

Other simple options include the crate taxi amps. Which at their core are designed to be portable. Their taxi limo amp is quite good, can get quite loud, and can be had for inexpensive. If purchased used, they usually only need a battery change which is a 20 dollar part from amazon. They charge with a 12v wall wart.

 

[George90]

Hi, I'm dealing buying a Fisher Loudbox Mini and need help make a mod bypassing its internal tranformer and give power to it directly from a car battery for busking, I've done this on a cube street ex but that has already the battery powering option so it was easy to do. I will upload the fishman schematics and a photo of its tranformer. Also could anyone tell me for sure guided from the schematics if the board uses ~13-14 V ? Thank's for helping.View attachment 129481View attachment 129482.fismnan schematic

Why not get a 12vdc to line voltage inverter? Seems much easier.

Thanks, the inverter idea seems the best option even though its an extra gear you have to carry. Busking depends a lot on moving around and change spots with the least amount of weight.

 

[George90]

The power-supply is using + and - 33 Volt for the amp , than lower it to + and - 14 Volt and also +3,3 Volt.

So you will need 6 car-batteries with the amp , or 2 without amp...

Hi, thanks for the reply, it's weird because they make the same version with a 12 battery inside it, but i cant find the schematic of that model.

https://www.thomann.de/gr/fishman_loudbox_mini_charge.htm

 

[Gold]

Inverters can be small and light. You want a ‘pure sine wave’ type. Otherwise the output waveform looks as chopped as it is. Scary.

Most of them are for use in solar power installations. You don’t need many features so look for a simple one more geared towards marine or auto.