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Old 25th June 2013, 09:12 AM   #1
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Default Amp to small boombox?

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!
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Old 25th June 2013, 11:16 AM   #2
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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.

Last edited by Saturnus; 25th June 2013 at 11:19 AM.
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Old 25th June 2013, 12:02 PM   #3
nertia is offline nertia  Scotland
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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.
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Old 25th June 2013, 12:07 PM   #4
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Quote:
Originally Posted by Saturnus View Post
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-Min...item232c3ce9cd

http://www.ebay.com/itm/Version-A-TD...item4d0b407b4d

Last edited by g0liat; 25th June 2013 at 12:22 PM.
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Old 25th June 2013, 12:28 PM   #5
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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!
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Old 25th June 2013, 12:36 PM   #6
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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.
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Old 25th June 2013, 01:21 PM   #7
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Quote:
Originally Posted by Saturnus View Post
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)
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Old 25th June 2013, 02:20 PM   #8
Mihkus is online now Mihkus  Estonia
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Quote:
Originally Posted by Saturnus View Post
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...
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Old 25th June 2013, 02:23 PM   #9
danzz is offline danzz  Spain
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Check this thread...
http://www.diyaudio.com/forums/class...han-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
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Old 25th June 2013, 02:56 PM   #10
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Quote:
Originally Posted by Mihkus View Post
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%.
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