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/diy/ - Do It Yourself

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194494 No.194494 [Reply] [Original]

anyone ever wired a deep cycle battery to a guitar amp?
if not, what is the loudest portable system you've made?

>buyfags take note
what is the loudest speker/boombox system i can plug into with a 3.5mm jack that i can buy?

>> No.194505

Batteries are DC, that amp like takes AC.

You'd need an inverter, which will introduce wasted electricity into the mix.

>> No.194518

>>194505
If you were to take that route, there's both a waste power, and potentially lots of noise added, especially playing with distorsion, since inexpensive inverters output the most disgusting square waves ever.

I guess OP means is connecting the battery directly to wherever its DC supply is, since amps take AC inputs, but internally they use DC anyway.

Never had a proper guitar amp, so I've never tried it myself, unfortunately.

>> No.194525

OP is trying to blast classical music at the bus station.

>> No.194548

Go buy a DC powered amp, they're usually 12V anyway.

>> No.194565

>>194518
Non-sinewave AC power shouldn't be much of an issue with supplying a tube amp, since tube amps are going to have a large low-pass filter on the power supply: namely, the power transformer.

>> No.194571

buy a car amp

>> No.194575

>>194571
Fucking bad idea and you should know why.

Car amps are to amplify canned music.

>> No.194576

>>194575

he doesn't want a portable guitar system, he wants the loudest portable thing that will drive a speaker.

>> No.194578

>>194576
You might want to read his post again and this time use your brain.

>> No.194579

>>194578

you should, you fucking dolt.

>> No.194580

>>194579
NO U

>> No.194829

before i start ripping apart my old amp, anyone know how likely it is that the power supply puts out 12vdc?

>> No.194830

>>194829
Unlikely.

>> No.194842

>>194494
Actually the biggest issue with non sinewave inverters are higher harmonics, not 60/50Hz hum

>> No.194851

>>194830
so do you think it'll probably be 5vdc?

>> No.194859

>>194851
No it'll probably be higher, a few dozen volts, maybe more depending on how powerful your amp is.

>> No.194862

>>194859
ok. is there a way to find out exactly without plugging it in and testing it with a meter?

>> No.194865

>>194851
If it's a tube amp then there will be several hundred volts.
If you really must insist on having battery power for your guitar amp then you'll need to use an inverter.

>> No.194868

>>194865
well shoot. and no it's a transistor amp.

>> No.194869

>>194862
You can make a very rough guess knowing the amp's maximum output power for its recommended speaker load. Loads are usually 8ohms. P=V^2 / R. Keep in mind the relationship between an AC sine wave voltage and DC voltage for equivalent power into a resistive load.

You can see if the schematics are findable with some googling.

You can give the amp an input sinewave and measure the output voltage. Try this with no load, or a dummy 8 ohm load so you don't ruin any speakers.

>> No.194870

Get a portable PA box. You can plug in an electric guitar and it will play clean sound just fine. Add fx pedals and you can get distortion etc.
They're quite cheap too. Or you could get a used/broken one, remove the power supply + battery and replace your amps power supply with it. Maybe you'll have to build a custom case to fit it all inside, but apart from that, it should be pretty straight forward.

>> No.194871
File: 163 KB, 598x1000, 1-800-wat.jpg [View same] [iqdb] [saucenao] [google]
194871

>>194870
thanks for the idea, but i'm not looking to buy something. i have a shitty old amp and a deep cycle battery and i want to blast grunge music when i'm outside.

>> No.194878

so i found a schematic for my amp. and i see that it has 23 and 12vdc.

can this resurrect my batter idea at all?

>> No.194880

>>194878
Neat, got a link?

>> No.194881
File: 98 KB, 890x442, power supply.png [View same] [iqdb] [saucenao] [google]
194881

>>194878
well shit.

here is the schematic for the power supply. will post full if asked.

>> No.194882
File: 73 KB, 890x442, power supply-edit.png [View same] [iqdb] [saucenao] [google]
194882

i am pretty sure this edit to the power supply will work. however i'm fuzzy on what to do with the red line.

>> No.194883
File: 395 KB, 1601x950, schematic.png [View same] [iqdb] [saucenao] [google]
194883

>>194880
here's the whole thing.

>> No.194885

>>194883
Peak to peak you have 23 * 2 or 46 volts.
If you're doing this directly from 12V batteries you're going to need four.

>> No.194887
File: 13 KB, 275x339, some stupid shit.jpg [View same] [iqdb] [saucenao] [google]
194887

>>194882
Hook it up like this.

>> No.194889
File: 84 KB, 500x375, 1323671439269.jpg [View same] [iqdb] [saucenao] [google]
194889

>>194887
awesome, thanks!
>pic related

although this does kill my idea :|
i don't have 4 12v batteries lying around...

>> No.194904

>>194889
Maybe you could build a DC/DC converter. i don't know if you have any electronics experience
but maybe you can look into something like this.

http://www.ti.com/product/uc2572

there is a typical application on page 4 which you can change to create -12 and -23Volts.
Making PCB's for these kind of things is actually kind of hard so maybe there is a prebuild option.

BTW; TI gives out free samples for pretty much everything they have,
just give a valid e-mail address and write your own name in the company section
or say you're a student.

>> No.194908

>>194904
could work. but tbh i really didn't want to have to work very hard on this. i had the stuff lying around and wanted to smash them together Transformers style and get something cool.

and iirc dc-dc converters that put out the amperage i'd need are expensive.