Need Some Help (Home Project)

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
OK my son came to me last week and ask me to build him a car audio amp so i told him i will try to do my best. I have a good idea but i am not sure on some of the parts on the schematic i have a clear idea i know some of them are capacitors but i want to be 100% sure here a picture of the schematic the areas highlighted in yellow are the parts i am not sure what they are. I will appreciate any help you guys give to help complete this for my son.

An externally hosted image should be here but it was not working when we last tested it.
 
First off there is something missing from the schematic. It shows the power supply rails as +Vcc and -Vcc. The diagram does not tell you that these voltages are +50v and -50v for an 8 ohm load, around +35v, -35v for 4 ohms.

To get these voltages from your 13.8v car battery you have to make a switching power supply to get the 70 or more volts you need. You could bridge a couple of amps together and run a lower voltage but you still have to do the same amount of work to get the voltage up.

It does not sound practical for someone that does not know their way around electronics.

Building high power car stereos is not something you just throw together. While I have no problem building amps for home I just buy mine for the car ready made.
 
Update i decided to go with the STK-4050V it more simple then the STK-0105 and it more power. I do have one more question on the far right of the schematic there a component marked RL what is it? and where can i get it from.

An externally hosted image should be here but it was not working when we last tested it.

RL is Resistor Load or more commonly your speaker.

I know I brought this up before but I will ask again.

Your new chip's data sheet 'Recommended supply voltage = +/- 66 volts. Where are you going to get it in a car?
 
RL is Resistor Load or more commonly your speaker.

I know I brought this up before but I will ask again.

Your new chip's data sheet 'Recommended supply voltage = +/- 66 volts. Where are you going to get it in a car?
(speaker) well i feel like a ***:deer: i have a power supply that will take care of it power needs when i am done schematic i will post it. It based on the power supply from a rockford fosgate 800a2
 
Hi, Whilst I admire your enthusiasm, I have to caution you high power amplifers are not easy to design. There is a very real chance of getting positive feedback at some frequency and the whole thing overheating and buring out.

The good news is, there are lots of people on here who will be happy help.

However more bad news. I just had a look at the fosgate 800a2 PSU sch and this is a high power switched mode PSU. Making this work will make the power amp look like a walk in the park. Seriously unless you have someone who knows about switch mode PSU magnetics and is prepared to give you alot of help or you can just buy all the bits and make an exact copy, I wouldn't go near this.

The truth is if you just want a cheap high power amp for your son the best bet is to buy one second hand, it will work out cheaper. The only reason to get into designing this yourself would be if you want to learn about Audio electronics. In which case I would recomend starting with something you have got a much better chance of making work.

I know this sounds really negative and this is a DIY audio site, but you could end up putting alot of effort into this and getting nothing but burnt out FETs. The power amplifer is a real possibility with some help from people on this site (it will still not be cheaper than buying one buy the time you have a PCB and a decent enclosure) but I would recomend stearing clear of the switch mode PSU.

Regards,
Andrew
 
Actually my thoughts also.

A switched mode power supply is a tricky beast for someone without much experience in electronics. If you wanted to do a car project maybe you can start off with a bridged amp that runs off of the battery voltage.

Use this for four channels of midbass/high end speakers and pick up a high power amp for a sub. Also you can build an electronic crossover to feed the two amps.

If you want to get real fancy you could also triamp. After this if the bass amp still looks interesting give it a try.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.