TA2020 in car

[kkyak]

HI,
I'm kinda new to this... but i have been wandering will it be feasible to try a TA2020 amp on a car. The alternator would give from DC 12 to 15V. The TA2020 max voltage is at 14V. I assume anything more would premature kill it. If i drop and regulate the voltage to 13V it will be safe right?
I was also thinking to add a tube preamp after the source input before the amp. Please see the attach image and tell me what you think. Is it advisable to try?
Thanks.

 

[!]

In theory yes you can do it but the details are a little off. For example you'll probably have an average (car running) voltage of 14.something volts, so if you want to have 13V you'll need a LDO (low dropout) regulator to end up with 13V, but when the car isn't running it may or may not be able to regulate to 13V as the battery is already down around 13.8V at full charge. In other words you'd have better chance of success if regulating down to 12.something voltage instead of 13.0V, or just using two silicon diodes in series to drop roughly 1.4V off whatever the voltage is at the time, running car vs engine off.

However, TA2020 max operational voltage is 14.6V instead of 14.0V, and absolute max rating (to avoid damage) is 16V... you could run one without regulated lower power in a car but you may find there is ignition noise if you don't regulate (maybe even if you do) and possibly add some ferrites for filtering the power leads.

A tube preamp is less than ideal in a car because of car operating and road induced vibrations. You might be willing to go to the trouble building a custom shockproof suspension for the preamp, but otherwise I would go all solid state or just skip the preamp.

 

[kkyak]

Thanks ... I get what you mean. I will try out without the tube preamp.
The voltage regulator that i intended to get is this 5 Amps Voltage Regulator Module Board, Out 1.5-32V | eBay

 

[!]

Since you will already have DC power from the car, you should remove the bridge rectifier from the circuit board so you aren't losing an additional ~ 1.4V and use jumper wire to complete the circuit from the input and output pins.

Also, LM388T isn't a LDO type regulator, it's going to cause more voltage loss. For example if your car's electrical system were at 14.2V and the amp at 3A current, the regulator at roughly 50C temperature for this example, your dropout voltage is about 2.5V.

So, even if you get rid of the bridge rectifier as suggested above, the highest voltage would be 14.2V - 2.5V = 11.7V, but with the car off and the battery down closer to 13.7V, you're at max 11.2V so if you want to be able to play the amp without the car on you would have to set the regulator to output no more than 11.2V and ideally you would leave a little margin setting it even lower like 11.0V.

I'm thinking you are better off with a different regulator like LM1084, also 5A and pin compatible with the LM338 on that ebay board, but with a dropout voltage only a little above 1.0V, then set it up to output about 12.5V.