Amp to small boombox?

[g0liat]

Hello guys,
I'm going to build a primarily small and cheap boombox, with 4" speakers probably and something like 30x10x10cm.
But since im quite a rookie I'd need some help with chosing the amplifier for this project. I'm going to use a 4Ah battery so they don't have to have super efficiency i think but correct me if im wrong..
I've looked around on Ebay and found these two:

#1 is 10W Class D with PAM8610 chip
Mini Amplifier Board 10W 10W Class D Stereo Audio Amplifier DC 12V 20mA D Level | eBay

#2 is 15W with TDA7297 chip
TDA7297 Version B 2 15W Audio Amplifier Board Dual Channel AC DC 12V New | eBay

So which one would you prefer due to quality, volume and soundquality?
Or have I've missed any facts?

Thanks in advance!

 

[Saturnus]

Both listings are removed.

But one would have to be rather silly to use a class AB amp (TDA7297) with a battery that small. Battery life might be less than 2 hours with that amp and that battery.

Always go for class D amps.

 

[nertia]

I Like this one for 4-6 ohm speakers. Nice build quality, flexible voltage range, very good sound for the price:

Hifimediy T1-M TK2050 9 - 24V

Might be a bit large or pricey for your project though.

 

[g0liat]

Both listings are removed.

But one would have to be rather silly to use a class AB amp (TDA7297) with a battery that small. Battery life might be less than 2 hours with that amp and that battery.

Always go for class D amps.

My bad, had them listed by Time ending soonest....

Okey so the difference is really that big with class D amps? Cause I have the ta2020-amp in another boombox with 6,5" and 7,2Ah battery and it plays for hours and hours.
So I thought I could cut a few hours and have 15W but ~2hours playtime is way to short, and due to your reputation about the boominator I trust you!

New links anyway:

http://www.ebay.com/itm/1pcs-10W-Mi..._Audio_Amplifiers_Preamps&hash=item232c3ce9cd

http://www.ebay.com/itm/Version-A-T...037?pt=LH_DefaultDomain_0&hash=item4d0b407b4d

 

[g0liat]

My bad Saturnus, had them listed by Time ending soonest....

Okey so the difference is really that big with class D amps? Cause I have the ta2020-amp in another boombox with 6,5" and 7,2Ah battery and it plays for hours and hours.
So I thought I could cut a few hours and have 15W but ~2hours playtime is way to short, and due to your reputation about the boominator I trust you!

Can't get any link to work but here is the ID-numbers of the auctions instead, just put them in the searchfield on ebay.
151066044877
400460587888

And yeah a bit too pricey but thanks anyway nertia!

 

[Saturnus]

Yeah. A class AB amp uses 4-5 times as much power as a class D amp with the same power output. It's a huge difference.

 

[g0liat]

Yeah. A class AB amp uses 4-5 times as much power as a class D amp with the same power output. It's a huge difference.

Ok thanks, good to know for the future!
So what do you think about this amp then, will it be able to play relatively good/high with 4" coax or maybe even computer speakers? 151066044877 (copy paste to ebay searchfield)

 

[Mihkus]

Yeah. A class AB amp uses 4-5 times as much power as a class D amp with the same power output. It's a huge difference.

Not really... class A is watt sucking monster if you want 10W and effefficiency
Below 10% or less
Class AB can be around 50-70%
Class D around 80-90%

Not very sure tho...

 

[danzz]

Check this thread...
http://www.diyaudio.com/forums/class-d/231988-what-heck-its-less-than-lunch.html

Its about the tda7297, people talk very good about it, another choice its the one based in the tripath 2024... Here is a link TA2024

 

[Saturnus]

Not really... class A is watt sucking monster if you want 10W and effefficiency
Below 10% or less
Class AB can be around 50-70%
Class D around 80-90%

Not very sure tho...

You are right not to be sure. It is fact that they use 4-5 times more.

Whole problem lies in that actual efficiency at maximum output where class AB is decent is completely irrelevant. Music has an average level that is 8-10 times lower than max RMS, so it's the efficiency at 10% of max RMS that is the actual efficiency of an amp. And here class AB amps are abysmal, usually 15%-20%, while class D amps are still very good at 65%-80%.

 

[LumpyLouis]

g0liat, have you made any progress with your small boombox?

I own a TDA7297 and a TA2024 and can definitely vouch for the TAT024 running 2 2.5" 4 ohm speakers in series (8ohm) per channel for at least 6 hours on my "4800" mAh Chinese Li-po on high to max volume continuously.

 

[g0liat]

g0liat, have you made any progress with your small boombox?

I own a TDA7297 and a TA2024 and can definitely vouch for the TAT024 running 2 2.5" 4 ohm speakers in series (8ohm) per channel for at least 6 hours on my "4800" mAh Chinese Li-po on high to max volume continuously.

Hello, no I haven't start building it yet, but I've got all the components so maybe tomorrow(today) I'll start. I bought the 10W amp and it plays really good with my old boombox with 6,5" koax speakers so I think I'll be satisfied with it!
And im using a 5,4AH battery cause I had it lying around so maybe abit to big but well the measurements will be 36x12x14 so it still qualifies as a small one Will post some pics here maybe if its possible

 

[g0liat]

Hello again, my boombox is now in progress.
But I would like to have a connection on the box that I can connect the charger to when the battery needs to be charged, without opening the box. So what is the best way to do this?
My first thought was to use a DC-plugg (2,1x5,5mm) but then I realized that it would be way to easy to get a short circuit this way if I have the stereo with me in the boat or when it's raining. So next thought then was using RCA-connections and put them a few centimeters apart from eachother, but is it possible to force that much electricity from the charger through RCA? Or what other ways are there?
I'd appreciate all tips!

 

[Saturnus]

Cigarette lighter plug for marine use.

 

[g0liat]

Too big to fit in :/ Only got somewhere around 20-25mm of height