12V Car Amplifier..

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zx3chris said:
this is not a very good chip, the thd is extremely high, you only get about 3 watts out of it before u hit 1% thd with a 4ohm load... im not sure if u could bridge it multiple times, but it might jsut be easier to construct a car amp the traditional way

the traditional way is a PITA! ,caz u'll need to build a good reliable
SMPS unit and that really sucks!
 
try the TDA1554
2x22W at 13.8v

I've used these in a 4 channel car amp, and they do the job quite well. They're loud enough for me ( I run one per speaker at 4ohms, so with 4 channels you get about 80W before the distortion gets noticable when you're driving )

They aint exactly HI-FI , but then without some attention to SMPS you won't get much power at 12v.

you can bridge them if you want, you may be able to parallel them too , but my hearing means more to me than the need for more power in a tin box...

the specs claim 22W at 0.1%THD, ymmv.

ray
 
TheFettler said:
try the TDA1554
2x22W at 13.8v

I've used these in a 4 channel car amp, and they do the job quite well. They're loud enough for me ( I run one per speaker at 4ohms, so with 4 channels you get about 80W before the distortion gets noticable when you're driving )

They aint exactly HI-FI , but then without some attention to SMPS you won't get much power at 12v.

you can bridge them if you want, you may be able to parallel them too , but my hearing means more to me than the need for more power in a tin box...

the specs claim 22W at 0.1%THD, ymmv.

ray

i already built a 4channel ver. of the TDA1554 Amp. , driving a 2
6x9 coaxials and 2 tweeters out of a good discman in ma car,
its really a good starting project if anyone wanna get as far as
possible from SMPS issues..

but to enlighten u, its putting 2channel x 22watt max. working in
the BTL mode .. so its already bridged therefor itcant be bridged
to get more power according to my tiny knowledge..
and the THD is 10% at full power (22watt), not as u mentioned
b4 (0.1%)...

ijust need to know any other amp. ICs that works from a 12V. source and can be bridged ,,ijust try to build the most powerful
12V amp. as possible to drive a Subwoofer..

sounds crazy but am just trying... ;)
thanx..
 
if you are trying to build it yourself for cost reasons, u cant beat the JBL BP powervalve series... you can get the 1200.1 for <$300 and it delivers 1400 watts continous. or the 600.1 for under $180 and it delivers 700 watts continous... definitley the best watt/dollar ratio.. also check out US amps, they are very good and underrated as well...

-chris
 
but to enlighten u, its putting 2channel x 22watt max. working in the BTL mode ..

yes, you are quite right , sorry it's a while since I built it, and I,ve slept since then :cannotbe:

I should be more careful about spreading mis-information;)
I realised after I'd gone home that I wasn't quite right....

ray
 
Re: tda7375

ppfred said:

Hi,
From Zetex the ZXCD1000 is a class D audio amp that you can gang up to get up to 100W @ 4ohms, available from DigiKey. A developers kit is also available.

Try for design guidelines and App Notes
Hope your less angry now.
pf

well, this one doesnt fit in here as it needs 35V. supply..
same prob.!

Paulr said:
bridged the tda7375 gets 26watts @ 10%.....not much better, could these be parralleled to get a bit more?

the TDA7375 isnt much diff. from the TDA1554..

the ques. in here is:
the TDA1554 can output 11watt x 4channels in unbridged configuration,, so can we bridge many of them to achieve certain
output power?!
and if its ok ,how it can be done?
 
the problem is physics, not the chips

You are very limited with a 12 volt supply, period. Until you build a power supply to increase the voltage, the only variable you have to work with it the impedence of the speakers. Even if you took drivers that worked at 2 ohms (serial connect 4ohm duals), and the chip could go rail to rail (+12 to 0), and was perfectly efficent.. it would be 72 watts. That is not happening, so if you want high power, you have to build some sort of powersupply.

And not to tell a DIYer to give up, the reality is that building one of these will likely cost you more than buying one. If you still have a desire to do it - do what others have done. Find a chassis of a highpower amp that no longer works. Start with its powersupply. However, be careful of outragous ratings - 200watt car amps rarely are. (but I suspect you know that).
 
I think you are really up against the edge of the envelope here.
Even bridged you won't be able to get much more power then the TDA1562 can develop.

It has a cool SMPS type voltage-lift for the output devices to raise the output power.

my back-of-the-envelope calculations suggest that you can't get more than about 72W in BTL mode at 12v , no matter how many devices you run in parallel , unless you find a way to raise the supply voltage.

sine wave in BTL into 4Ohm load:
I = V / R gives us

((12+12)*0.707) / 4 = 4.242 Amps

P = I^2 * R gives us

4.242^2 * 4 = 71.9 Watts

and thats assuming no losses and an infinitely low resistance for the output devices.

Into a 2R load you *may* be able (theoretically) to get about 140W , but you better have no losses anywhere...

maybe a pair of 4R high efficiency drivers in an isobaric configuration.....

ray

actually you'd be better off using higher efficiency speakers to raise the SPL than trying to get more and more power. Try some Pro drivers like Eminence or ElectroVoice - 102dB/W or higher - rather than the cheap low-efficiency things that usually masquarade as car subs.
 
car amp

try the tda7396 45 watts into 2 ohm @ 12 to 18v dc look up the data sheet from st gives you the layout as well also you can get these from electronic goldmine for a 1.99 dirt cheap im using one for a guitar amp and it rocks. hooked it up to a car system and not bad for one chip. you can combine chips but still working on it
 
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