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Home Car Audio Build

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abillybob94 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote abillybob94 Quote  Post ReplyReply Direct Link To This Post Topic: Home Car Audio Build
    Posted: 10 March 2018 at 9:50pm
Hello All

Hoping you experts can help me through this as I've put weeks worth of my own effort into a little speaker project of mine. It's all currently working but not perfectly.

So this is what I have currently

https://www.ebay.co.uk/itm/DC12V-LED-Transer-Driver-LED-Strip-Light-Power-Supplier-AC110-240V-to-DC12V/121868546386?ssPageName=STRK%3AMEBIDX%3AIT&var=420863278322&_trksid=p2057872.m2749.l2649 - This is the PSU, it's a cheap PSU rated at 40 amp and converts 240v AC to 12v DC

https://www.ebay.co.uk/itm/UK-Single-1-DIN-Car-DAB--Bluetooth-Stereo--Unit-MP3-USB-SD-AUX-IN-FM/401402958954?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 - This is the headunit, again nothing special and fairly cheap but would do what I'd need it to

I have 4 Edge 306 speaker which includes the crossover for 4 tweeters

I have an Edge amplifier.  http://www.halfords.com/technology/car-audio/car-amps-subs/edge-ed7300-2-channel-stereo-amplifier - This one to be exact. Which is wired up to a small 8" Bass Face Subwoofer for some kick in the bass... not too much and the gain isn't very high neither is the frequency just enough.

So that's what I've bought a long with some MDF woof and other bits and bobs to create a big floor standing boom box.

It all works perfectly but I find intermittently the Headunit goes into what I think is protect mode. A restart of the headunit seems to remedy it and it will work again for a while but sometimes this can be 3 hours sometimes it can happen in 5 minutes. My thinking is it's the PSU as it's a cheap PSU and the power may fluctuate. I also get a low humming noise but only low volume so when it's turned up you can't hear it.

I also notice the subwoofer will "THUMP" when I turn the headunit off although if I turn this off before I turn the Headunit off it doesn't "THUMP" these are minor issue the main issue is the protect mode. Basically the headunit will just turn off all sound to the speakers although the headunit is still on 5 seconds after the music will come back on and then 5 seconds will past again and it will turn off... rinse and repeat until I restart the headunit.

I thought about buying one of those car audio capacitors a bit like  https://www.ebay.co.uk/itm/1-Farad-Power-Cap-capictor-with-digital-voltage-display/132473738500?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 - this one. Inbetween the PSU amp and headunit to hopefully smooth the power a bit when coming from the PSU.

Here's a quick diagram I knocked together of how I'm going to wire it. I just wanted to ensure this is safe to do? I've never used Capacitors like this before and I know you have to use a resistor that comes with it to slow charge it before installation which I can do no problem but my worry is that if we unplug the PSU from the mains for a while and plug it back in this capacitor will get for 12v delivered to it without being slowly charged, is this a problem for it or a risk? I also know that you have to discharge them before disconnecting out of a car and obviously when unplugging the PSU that won't be the case it will just loose all of it's power so is this safe also?



I know it's a long message and a lot to take in but I'm really struggling here and any help would be most appreciated. I already know that I probably should have just bought a home amplifier but I had my reason why I couldn't do this Sad

For those that are interested  https://imgur.com/a/QS0Cr - here is a picture of the box, still a work in progress need to sort out the white silicon and put that back on etc...
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mini-mad View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 10 March 2018 at 11:00pm
Stick a meter across the PSU. when you turn it all on at once there's a surge of power which drops the output of the PSU voltage. It could easily be this as most modern in car stuff has under voltage protection and the bigger the load (when it does work) the more the rails will sag under heavy bass...

More often then not there are output controls.. well, control pot anyway on these things which means you should be able to turn the output voltage UP. All car audio stuff can handle upto a good 14.4v before OVERvoltage protection kicks in. The cap you have won't really be that much help with power on but does help A LITTLE BIT when you are playing music.

I would turn the voltage up to at least 13.5v minimum and let the PSU charge the cap before turning on all the other bits... one at a time.

The reason it doesn't happen in cars is the big ass battery that takes a pounding day in day out with the starter motor so doesn't really sag in voltage to much for this to happen.
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 10 March 2018 at 11:05pm
...just checked. These IS a voltage adjustment pot on the right hand side of the PSU output terminals.

Also being 12v rails (well 13.5v hopefully) make sure you have nice big thick chunky cables going from the PSU to the cap and then to the bass amp.


Make sure it's all fused too... don't burn out your toys before you've had your fun!



Edited by mini-mad - 10 March 2018 at 11:07pm
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote abillybob94 Quote  Post ReplyReply Direct Link To This Post Posted: 10 March 2018 at 11:41pm
Cheers mate I appreciate your help.

I've looked on Youtube at the same PSU's as the one I have and I'm pretty sure it is only 12v, the voltage adjustment will only let it go up to 3% higher which I don't think is anywhere close enough to 13v let alone 13.5v. Is this a problem then?

Is it safe to use a Capacitor in the way I want to? I'm worried about it discharging and re-charging quickly when the power cable is plugged into the Wall, I haven't actually purchased it yet so do you think I should skip the capacitor idea?

I did think about getting another Power Supply but I don't have a clue of what to buy, I don't want to spend through the roof either and it needs to be fairly compact so linear PSU's are out of the question. Anything that you think might remedy the issue that you can point me to? 

:) Thanks again!!


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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 10 March 2018 at 11:46pm
Originally posted by abillybob94 abillybob94 wrote:

Cheers mate I appreciate your help.

I've looked on Youtube at the same PSU's as the one I have and I'm pretty sure it is only 12v, the voltage adjustment will only let it go up to 3% higher which I don't think is anywhere close enough to 13v let alone 13.5v. Is this a problem then?

Is it safe to use a Capacitor in the way I want to? I'm worried about it discharging and re-charging quickly when the power cable is plugged into the Wall, I haven't actually purchased it yet so do you think I should skip the capacitor idea?

I did think about getting another Power Supply but I don't have a clue of what to buy, I don't want to spend through the roof either and it needs to be fairly compact so linear PSU's are out of the question. Anything that you think might remedy the issue that you can point me to? 

:) Thanks again!!




What's is for?... it's cheaper to buy a second hand PA amp then to go the way you are... So, why?
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 10 March 2018 at 11:51pm
Ok.. just 're read.

So!... I would use an old ATX power supply to save a bit of £££ and tie all the 12v rails together. There's a ton of tutorials online on how to do this and if you can get a 500-600w PSU all the better!

The cap is an ok idea but at least let it charge up for 5-10 seconds before you turn the sub on 1st and then the head unit.

It's cheap and it's a bigger power supply.
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 11 March 2018 at 12:06am
ATX PSU tutorial

a better tutorial...



Edited by mini-mad - 11 March 2018 at 12:13am
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote abillybob94 Quote  Post ReplyReply Direct Link To This Post Posted: 11 March 2018 at 11:30am
Would it be ok to use a computer PSU? Would I not have similar issues with a computer Power Supply as it’s also switch mode? I’ve found a good one at just £17 that will deliver 44amps over the 12v Rail.

Here it is what do you think?

https://www.ebuyer.com/566863-ace-black-120mm-fan-600w-fully-wired-efficient-power-supply-psuace600br

Thanks again for your help pal!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 11 March 2018 at 11:53am
The idea was to use what you already had...

Why are we going 12v again? Is it just because of the car bits that you have? Would it not make waaaaaaay more sense to start over and use domestic hifi/small PA stuff instead?

I don't see throwing money at this problem a good idea. If you can hack at things you already have, then yes, go ahead. But buying parts to suit a 12v/230v hybrid isn't the best idea and won't be anywhere near as good as either in the own environment.

If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote abillybob94 Quote  Post ReplyReply Direct Link To This Post Posted: 11 March 2018 at 12:06pm
Yeah I’m a bit stuck using just 12v car stuff. I couldn’t find a decent home amp that would give me 4 channels and 4 ohm compatible plus I have a subwoofer to power so wouldn’t I need another amplifier to power this?

It then suddenly gets quite expensive, plus home amps are normally fairly big and won’t fit in the box I’ve built...

I don’t mind spending a bit of extra money to improve things and it does sound really good when it’s on I just need it to stop turning itself off over time. I’m presuming that getting a computer PSU would be a better option as surely these have smoothing capacitors already in them and can deliver the power I would need?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slaz Quote  Post ReplyReply Direct Link To This Post Posted: 11 March 2018 at 8:19pm
I'd say the cause of the switch-off is one of 2 things :-

1) The PSU will be designed for constant loads - it could be that peaks in the music are sending the current draw up to a limit and causing the PSU to go into self-protect.

2) Something thermal (i.e. overheating.

I'd try connecting a bulb (or mebbe 3 LEDs in series + a resistor) across the 12V supply - and then more or less watch the light - if it goes out corresponding to the sound cut-out - then it'll be the PSU.
If not, look at the amplifier .... does it get hot ?

Oh yeah - the power rating - most car amps o/p is rated at a supply voltage of 14.7 V or so .... with a 12V supply your o/p will be about 60-70% of whats quoted.



Edited by slaz - 11 March 2018 at 8:21pm
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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