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Avarollin?
1996 Avalon XLS
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932 Posts
Discussion Starter #1 (Edited)
I was cleaning out the garage and stumbled across my factory amplifier out of my 1996 Avalon XLS with 4/6 speaker sound system (no oem subwoofer). Before recycling the chassis for something else, I decided to do some dirty documentation on it for anyone interested.

While it appears to have a big coil of sorts (was thinking it was for SMPS, but is probably just for power/noise conditioning), the capacitors are all rated 16V, so can only assume the amplifier rail voltage is just the raw battery voltage.
The amplifier is composed of multiple Toshiba TA8221AH, a 2-channel BTL amplifier IC chip rated for up to 30W each channel.
Datasheet link: TA8221AH pdf, TA8221AH description, TA8221AH datasheets, TA8221AH view ::: ALLDATASHEET :::

Physically, my board is composed of two of these 30Wx2 chips with a position for a 3rd one blank. This gives 4 total amplifier channels. I assume the 3rd one may be used for the OEM subwoofer if equipped, and then would be likely bridged... but i don't see a mention of it. I also may be completely wrong if the OEM sub uses a separate amp module.

At 14V, the amplifier chip can drive 2ohm load at ~29 watts per channel, and a 4 ohm load at ~22 watts per channel. While these numbers aren't crazy, these do appear to be RMS values, and would give most aftermarket HU's a run for their money as far as amplification power goes.

311086


The THD (of the chip, i cant assume for the rest of the box) is pretty low, which is cool, but runs away quick the closer it gets to its maximum power. The chart on the left is showing a static supply voltage at 13.2V with 3 different frequencies tested. Alternatively the chart on the right shows a single 1khz tone at different supply voltages. My main take away here is at 14.4V, at 4ohms it will deliver up to 18W @ 1% THD.

311085


Location:
It is a rather unassuming aluminum box located behind the passenger glove-box. It is nestled between the wall and other BCMs, outlined in red below.

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It is the unplugged module in this picture:
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Removed out the vehicle it looks like this:
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Guts:
Front
"Harman Motive 285410"

Fun fact, Harman International is a division of Samsung, and Harman owns other brands such as JBL and Infinity.
311089


Rear
311091


Amplifier ICs:

311092
 

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480 Posts
Nice write-up. I'm planning on taking mine out and putting it in a box in the attic. Good thing is, most powerful newer Class D four channel amps are small enough to probably mount in the same place as the factory amp. Just have to fabricate a mounting bracket.
 

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Avarollin?
1996 Avalon XLS
Joined
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932 Posts
Discussion Starter #3
Yeah - matchbox style amplifiers are so readily available now, I was really asking myself why I was even bother writing it up. I figured it was more useful as a: "should i keep this amp installed + wired to the speakers or bypass it to use the integrated HU amp".

And you know, science.
 

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480 Posts
Hey Jigg, did the factory HU get it's ACC, ground and constant 12 volts from an OEM amplifier pass thru circuit? Wondering if it's necessary to keep it plugged in even if one intends to bypass it with aftermarket gear.
 
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