Memory Wire for in home headunit

blocco a spirale

Joined Jun 18, 2008
1,546
I suspect that the "memory" wire also powers the unit and the "switched" wire just provides a low current trigger to tell the unit to switch on. The boost converter cannot provide enough current to power the unit and I didn't expect it would need to. I'll think about it, there are ways around this problem.
 

Thread Starter

John Deere

Joined Mar 19, 2016
14
I suspect that the "memory" wire also powers the unit and the "switched" wire just provides a low current trigger to tell the unit to switch on. The boost converter cannot provide enough current to power the unit and I didn't expect it would need to. I'll think about it, there are ways around this problem.
Ok thank you Blocco.
Installing a headunit, amp and sub in a car from scratch is a peace of cake, been doing it for years but in stalling one in the workshop.......lol
I Always like to try something different.
 

blocco a spirale

Joined Jun 18, 2008
1,546
You'll need to buy a bridge rectifier (see link below) it doesn't need to be exactly the same as the one in the link but if it looks the same it should be more than up to the job, you can find them on ebay as well.

Connect it like this and adjust the output voltage from the boost converter to 11.5V:
Radio Power.png

Now, when the high current supply is switched on it will be fed to both power inputs of the radio and the low current permanent supply will be cut off.

http://uk.rs-online.com/web/p/bridge-rectifiers/6290186/
 
Last edited:

Thread Starter

John Deere

Joined Mar 19, 2016
14
Hi.
I got a bridge rectifier, have it all hooked up but one wire.

Silly question...where does the 12v switched wire from psu go if the 12v switched wire from radio goes into rectifier?
 

Thread Starter

John Deere

Joined Mar 19, 2016
14
Ok so I figured it out.
But weird thing is, when you have radio cranking and put the psu in stand by, the booster seems to restart and you loose your saved memory, when radio is turned down a little and psu goes into standby the booster is fine. Weird huh

Cheers, Reuben.
 

blocco a spirale

Joined Jun 18, 2008
1,546
I think that when the switched supply wire is turned off, the radio does not switch off immediately so for a brief moment it tries to pull all its current from the boost converter which causes it to shut down briefly.

I'm not sure there's much you can do about this but you could try adding a capacitor of a few thousand uF to the memory wire at the radio end.
 

blocco a spirale

Joined Jun 18, 2008
1,546
It depends whether the input side "-" of the boost converter is isolated from the output side "-". If there is continuity between the two then you don't need to do anything otherwise they should be linked with a wire. It seems to be working so I assume that they are not isolated and you don't need to do anything.
 

Thread Starter

John Deere

Joined Mar 19, 2016
14
Hi Blocco,
Well have everything connected, mounted and put away nice and tidy.
PSU, Boost Converter, Bridge Rectifier and Stereo are all working correctly now.
Finally have good sound in the workshop thanks to you.

Many thanks Blocco couldn't of done it with out ya.

Cheers, Reuben.
 
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