Rep Power: 300

it's a Toshiba TA8264AH

http://www.semicon.toshiba.co.jp/eng...poweramps.html


it's interesting how the TA8273H is found in decks which people would consider better than stock yet it uses an amplifier that is very similar to the TA8264AH.


TA8273H = 25w *4 channel @ 13.2V and 10%THD (47watts max. per ch)
TA8264AH = 21w *4 channel @ 13.2V and 10%THD (41watts max. per ch)


THE DECKS FOUND IN THIS LINK ALL USE THE TA8273H
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http://carradio.al.ru/?i=bn&searchname=ta8273h



so what actually makes the aftermarket decks better than the stock one? the preamp?

also, since i can trace the line input into the amplifier IC, can i just tack on some wires and use the stock amp's input signal as a pre-out for an amp? will i have any problems if i do this? eg. will i gut a loud pop on the amp everytime i turn the car on?

 
Rep Power: 300

btw, maybe i'll go buy myself a TA8273H and install it into the stock deck to see if there's any dif...haha

 
Rep Power: 0

10% THD is totally unacceptable....

find me the power output at .1%, .5%, 1%, 5% and ill be your friend

 
Rep Power: 300

oh yea,

forgot to mention THD....

0.02% THD @ 5watts and vcc of 13.2V

Toshiba Datasheets really suck..that's all they'll list. it doesnt list how much power it'll output at 1% THD

anyways, it sounds as though a lot of aftermarket decks suck...heh..
IMO, these toshiba IC's are crap

 
Rep Power: 312

Its numerous things - including the design of the circuit. The amplifier is just one part of the who shebang. If the other parts that they used suck @ss than its not going to help (caps, inductors, resistors, etc). Don't forget the power supply. If its not clean, you're going to get some noise as well....

 
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so therefore, my theories are proven... if its 21 rms at 10% thd (completely unlistenable), and its a linear scale (doubtful), then at 7 watts, output will have a thd of 1.3%, which is totally unacceptable in anything above 150-200 Hz

 
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as to your issue about preouts, i still guarantee you itll suck. the preamp section is probably a piece of ****

 
Rep Power: 300

Other parts suck ***? it's possible but there arent very many parts inside a head unit. decks use highly integrated IC's and there isnt much circuit designing to do. the parts manufacturer gives them a reference schematic and that's what they'll use. the toshiba amp chips suck but then if kenwood and jvc are using the same chips in their $300 decks, then isnt it likely that they cheaped out on the preamp too?

also, the powersupply is limited by the car battery's supply voltage. decks dont use the switching power supplies found in amps because there's no space for it.

as for caps and resistors, the stock deck uses respectable name brand parts. eg. capacitors are made by "nichicon" which is better than those bulging caps found in motherboards :P
the toshiba amp chip requires very very few external components so lack of external components is not really an issue.

btw, the preamp chip inside the stock deck is a Philips TAA7704H. i'm sure it's not a very good preamp but i wasnt able to find the datasheet for it


anyways, what i'm saying is it seems that all cheaper decks use crap parts. it seems the only advantage of those decks are stuff such as a flashy faceplate, preouts, and mp3 playback. from judging by the parts found in those lower budget decks, sound quality wont be much of an improvement over the stock deck. it's not until you spend $400+ on a deck that you might get some quality components inside.

 
Rep Power: 300

ok i found the THD vs Pout graph

it shows 10khz, 100hz, and 1khz are all under 1% THD until it reaches around 15watts. that's when THD begins to skyrocket to 10% at a very steep slope

Vcc =13.2V
RL = 4ohm

 
Rep Power: 312

Yes, the manufacturer does give a "reference" design, however about 99% of the time the designer doesn't follow it. Most of the spec sheets you see are for amateurs. I can guarentee you that almost all of the manufactures don't follow that crap. Designing an amplifier is not a walk in the park my friend. Spending 5 years at an engineering school, I can tell you that there are a lot of things to consider - and yes, regardless if there is a lot of parts or not, they all still must be of good quality. All parts have a tolerance, be it 1%, 5% or 10%. Most manufacturers choose to use 10% tolerance parts because in the long run it can save them a lot of money. And again, the power supply matters. It doesn't matter if it is a switching power supply or not - noise can and will still get in. If they don't filter the power as well, your amp and preamp are going to suck *** - I guarentee it.

 
Rep Power: 0

first of all, thats the THD for JUST the output stage in a best case scenario. Thats not counting the preamp, the low low tolerance parts, the DAC's, and whatever else can induce distortion.
even if you dont count that,
anything even NEAR 1% thd is still sucky. i dunno if youve ever heard 1 khz at 1% thd, but you can definitely hear second and third order harmonics in it

 
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by the way, im happy, its been a LONG time since this site has had any respectable debates

 
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but its not only the preamp and the output chips that determine quality. youve got to take into consideration the onboard processing and the DAC's.

i bet the chip for whatever equalization the stock deck has is a piece of ****.

 
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perfect example of this is clarion and arc audio.
clarion makes some average amps, arc audio makes some beautiful amps.
about a year or two ago, you could open arc audio and clarion amps and the board schem looked almost identical, but with different heatsinks.
what happened was, arc and clarion both had the same OEM, but arc was obviously paying more money for the amps, because the clarions used all 5-10% tolerance parts, and the arc audio's are pretty much all 1% tolerance parts.

 
Rep Power: 338

you guys are all forgetting that our stock systems sound pretty good. they arent shitty at all.