building an audio amplifier w/Toshiba TA8251AH

[mclute0]

I picked up a couple of Toshiba TA8251AH for less than a cup of coffee.

https://www.goldmine-elec-products.com/prodinfo.asp?number=G15382

I have one bread boarded and it sounds pretty good, but I haven't been able to get it to consume over ~8watts for two channels. I know part of the problem is my 8ohm speakers and another part is the $3 Bluetooth module (HW-425) I am using to drive it doesn't do the even close to the 1+ volt need to get 100% output, maybe .75. The datasheet says it is 30w BTL x 4 channels, so I would be happy at maybe 20watt power utilization.

My biggest question for anyone willing to respond is, what is the best Vcc to this run IC at? Seems to me the best %THD bang for the buck is at 18V Vcc that is the listed operational voltage, but all of the specs are measurements at 13.7V. Yea, need to add a decent heat sink, but it doesn't look to me to be a big issue; however, I am no audio expert.

http://cdn.goldmine-elec.com/datasheet/G15382.pdf

[mariush]

It's a crappy car stereo amplifier, not sure why you'd want to bother with it.

Anyway, you should want to run it in the mode that gives lowest THD  ex:

Low distortion ratio : THD = 0.02% (typ.)  (VCC = 13.2V, f = 1kHz, POUT = 3W, RL = 4Ω)

As it's a car amplifier IC, it's supposed to run at around 13.2 - 14.4v, but datasheet says minimum 9v.

You can still get TDA2050 clones for around 50 cents each ... ex https://lcsc.com/product-detail/Audio-Power-OpAmps_HGSEMI-TDA2050TB_C434516.html
They work from 9v to 50v, either in single mode or split power supply (+/- 4.5v .. +/- 25v) but the higher the voltage the more output power (and also heat dissipation, they're around 60-70% efficient).

Screw them to a heatsink, get a 16.5v-20v laptop adapter or a +/- 12/15v transformer and you have a decent amplifier.
See https://diyaudioprojects.com/Chip/DIY-TDA2050-Hi-Fi-Chip-Amplifier/

[mclute0]

I got them to play with, just added to an order for some obsolete meanwell PPS150 power supplies that were on sale for dirt cheap. Combined with some just BT modules I have, I hope to make a couple of BT Speakers that I won't mind if they get destroyed at a party.

and it looks like I made a mistake on the output voltage from the BT card, it is only maxing out at 333mv at 1khz at 100% input from pc audio. That explains my problem.

[Kokoriantz]

These days such amplifiers are used for array speakers. Each channel can deliver about 7.5w unsaturated @8 ohms. Buy 8-16 full range 3"-4" cheap speakers mount them in a column.
The sensitivity is 0.2v rms to saturate. 

[Jeff eelcr]

Matsushita used them in a few vehicle OEM radios Toyota was
one of them. They sounded pretty good on the bench compaired
to a lot of others, but at 4 ohms not 8.
Jeff