unfortunately i don't acutually know how many watts I need. i would have liked to build a boombox to carry with me during a trip with my schoolmates...that is why i need 10 hours of continuous power. I need it to sound very loud in the bus we will be into (i think it will be a 50 seats bus ... i'm telling you this in order to give you an idea of the area i need to "fill with soundwaves") but also in an outdoor use...
I apologize for asking so many questions...
I apologize for asking so many questions...
There's a couple of amps here that might suit your needs - Car Amplifiers in the Car Audio Department at Parts Express | 378
Mike
Mike
Ciao quasi paesano
Now we are talking
1) it's good that you have 2 x 4 ohms speakers.
You can **easily** get 16W RMS into each
You'll need 2 amps , each one driving one speaker; you feed the same signal to both and each drives its own speaker.
I use TDA2005 , an oldie for sure but since I buy them in bulk I still have over 50 left, now the standard is some kind of TDA but with simplified pinout (fixed preset gain, etc.) or Class D car amps, quite inexpensive and available ready built from EBay and such.
2) I *commercially* make amplifiers, since 1969 and way over 10000 of them (should be around 14000 by now) , including battery powered ones, of which I made hundreds.
3) a very reasonable weight and size 12V 7AH battery will give you around 6 to 8 hours playing time, if you sing and play a guitar, or are a street performer (magician / puppeteer / Tango dancer / gymnast / acrobat / etc.) because sound output is not *continuous* (you stop between songs, say jokes, talk to the people, collect money, plain rest, music is background level , not full blast).
If it's a DJ type show, with continuous "linked" music played as loud as possible, no stops or silent moments at all, then halve battery duration.
If you need longer time, carry 2 batteries with you or a larger one.
This is my smallest "Callejero" , 30W biamped (a TDA2005 driving a 3.2 ohms speaker and a TDA2003 driving a 4v ohms LeSon Tweeter , very loud and clean)
for higher power from 12.6V batteries, you'll need switching converters (SMPS) which rise 12V to whatever's needed; in my case stiff +/-35V , for 60W@8 ohms and 100W@4 ohms amplifiers.
Of course the 60W one needs 2 7AH batteries for any long duration show and the 100W one is better fed from a separately carried car battery.
60W Bass amplifier:
100W Voice/Instrument amplifier:
So with 30W you are just on the limit of cheap/easy; any higher you'll need to get into switchers/choppers to step voltage up.
IF so, shop for car type amplifierts which already have whatever's needed "built in" , just be ready to carry a heavy car battery.
Nobody has asked about the audio source. How do you plan to feed audio to the amp/speaker combo?
A lot of sound could be made with only 10-15 watts/channel. Might not shake the walls but it's possible to get some good, quality sound. I can fill a room with 3 watts/channel operating from a 5 volt bank battery. I do it every day..
A lot of sound could be made with only 10-15 watts/channel. Might not shake the walls but it's possible to get some good, quality sound. I can fill a room with 3 watts/channel operating from a 5 volt bank battery. I do it every day..
No, most amps will self-destruct if you connect their outputs together, and no, it won't double the power into the same load. As other's have said, you might not need as much power as you think, especially if you're driving a high-efficiency speaker.
Mike
30W (15+15 into 2 speakers) is fine for your intended use, but a lot is dependent on speaker efficiency , what exactly are "2 x 4 ohms speakers"?
Brand/model/specs?
A link to their datasheet or page might help a lot.
For 10 hours operation, full blast, consider a car battery.
I suggested earlier a couple lighter 12V 7A gel/alarm batteries because they are a good compromise (cheap/not too heavy/reasonable power) for a street Musician, who may have to travel by Public Transport (bus/train/metro) carrying amp in one hand (look at the examples I posted), and instrument + accessories in the other, but for Bus use or if you have a car available, you may very well carry a heavier car battery. (36/40/45/50/55/60 AH)
Brand/model/specs?
A link to their datasheet or page might help a lot.
For 10 hours operation, full blast, consider a car battery.
I suggested earlier a couple lighter 12V 7A gel/alarm batteries because they are a good compromise (cheap/not too heavy/reasonable power) for a street Musician, who may have to travel by Public Transport (bus/train/metro) carrying amp in one hand (look at the examples I posted), and instrument + accessories in the other, but for Bus use or if you have a car available, you may very well carry a heavier car battery. (36/40/45/50/55/60 AH)
No problem. I see you've edited the first post
...
Other options are Class D amplifiers (probably the best bet for battery use), or you could look at bridged 'chip amplifiers' a little like the TDA7294 but even here you..
TDA7492p is mentioned (edited somewhen) in the first post, which is a stereo, bridged, classD amp, well suited for the task. (2x30W @ 4 ohm)
2*12V SLA battery is enough, or maybe too much, if volume control is used without self-control.
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I use a pair of these to power my system.
Everything including the TV is off the grid, my amp is a Yamaha AV amp and run a Blu Ray and Xbox too...
I get a good 20 hours of system run time, Sometimes I go a week in detween charges , sometimes a couple of days.
Big Pro driver DIY speakers, high SPL with movies.
Life P04 batteries are very expensive, but different world compared to lithium ion....Different galaxy compared to lead acid!
I use a pair of these to power my system.
Everything including the TV is off the grid, my amp is a Yamaha AV amp and run a Blu Ray and Xbox too...
I get a good 20 hours of system run time, Sometimes I go a week in detween charges , sometimes a couple of days.
Big Pro driver DIY speakers, high SPL with movies.
Life P04 batteries are very expensive, but different world compared to lithium ion....Different galaxy compared to lead acid!
There are such a lot of vendors and similar amps on eBay I cant believe nobody ships to italy. Search!
Yes, if you overdrive it. Otherwise its theoretically ideal, since peak voltage of a sinewave is 40 % higher than effective value, and also there is some drop both on amp and on battery. But a speaker is a very tricky animal, a single number cant describe it.
Actually if you get a 12V class D amp you may run it from the bus 12V outlet, no need to lug batteries around ;-)
But check with the bus company first.
Jan
Or, being in Italy, an accordion
Any acoustic instrument is way more fun, will make you the center of attraction and get you the best chicks. Guaranteed.
Small Mini Amplifier
ask them if they ship to Italy...20 watts. I am running one from 12v battery...
ask them if they ship to Italy...20 watts. I am running one from 12v battery...
it seems pretty good, but I need something cheap (because of the high prices of the batteries
)...maybe my next project will be something more "peculiar", but at the moment I only something powerful and portable.A part from this thanks for your suggestion.
About the speakers... I found those cheap one on aliexpress Trasporto libero 2015 hot 2x4 ''pollici altoparlanti auto automobile automobilistico hifi gamma completa di gomma da masticare altoparlanti di bordo in Spedizione gratuita 2015 hot 2x4 ''pollici Altoparlanti auto Automobile automobili
Hi again everyone... I've just found 4 6V 5 Ah batteries at my grandpa house . I'll connect them (if they still work) in series and parallel, so that I'll have 12v and 10 Ah.
I also found on eBay this amplifier. Do you think tha it could be good? 200W 12V Mini Hi-Fi Stereo Amplificatore Radio 2 Canali MP3 Auto Casa Super Bass | eBay
DROK® TDA2030A Amplificatore Digital Board 34W + 34W Dual Channel Modulo Stereo Power Audio Kit BTL Circuit DIY:Amazon:Elettronica
Sorry if I'm asking so many questions, but I don't want to blow everything up
. I'll connect them (if they still work) in series and parallel, so that I'll have 12v and 10 Ah. I also found on eBay this amplifier. Do you think tha it could be good? 200W 12V Mini Hi-Fi Stereo Amplificatore Radio 2 Canali MP3 Auto Casa Super Bass | eBay
DROK® TDA2030A Amplificatore Digital Board 34W + 34W Dual Channel Modulo Stereo Power Audio Kit BTL Circuit DIY:Amazon:Elettronica
Sorry if I'm asking so many questions, but I don't want to blow everything up
if you connect the batteries in series and use them for ±12Vdc you can get a maximum output of nearly 8Vac without the extra losses of a bridging arrangement.
That 8Vac gives you a maximum power output of 8W into 8ohms or 16W into 4ohms.
You want the highest efficency 8ohms driver you can borrow, to reduce the current consumption from the batteries.
You also want a power amplifier with an ultra low quiescent current, so that when playing quietly and/or not playing at all the batteries are not draining too quickly.
Get an acoustic guitar.
That 8Vac gives you a maximum power output of 8W into 8ohms or 16W into 4ohms.
You want the highest efficency 8ohms driver you can borrow, to reduce the current consumption from the batteries.
You also want a power amplifier with an ultra low quiescent current, so that when playing quietly and/or not playing at all the batteries are not draining too quickly.
Get an acoustic guitar.
I haven't understood very well the first part of the message... A part from that I already have an acoustic guitar
but I wanted to make a step further from it with this project...Hi again everyone... I've just found 4 6V 5 Ah batteries at my grandpa house
I also found on eBay this amplifier. Do you think tha it could be good? 200W 12V Mini Hi-Fi Stereo Amplificatore Radio 2 Canali MP3 Auto Casa Super Bass | eBay
DROK® TDA2030A Amplificatore Digital Board 34W + 34W Dual Channel Modulo Stereo Power Audio Kit BTL Circuit DIY:Amazon:Elettronica
Sorry if I'm asking so many questions, but I don't want to blow everything up
You provided 2 links. The ebay one is clearly fake, not 200W. Probably only about 2x15.
The other is OK, with 18V it gives you 2x 30 W, but consumes much more power than a ClassD, and needs a quite big heat sink.
Why you dropped TDA7492? It's better!
Old, not maintenanced SLA batteries are most often dead.
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