filter for sure t-amp in car?

[Perry Babin]

A ground loop isolator may make the amplifier usable with the head unit and the LOC that you have. A high power LOC with transformers would replace the LOC that you have and the ground loop isolator.

 

[majorahole]

would a high power loc degrade quality? i heard that only the expensive ones dont.
im trying to keep this as cheap as possible too.
i think im going to rewire the loc's from right behind the hu and run rca's to the amp instead of running the speaker wires to the amp where the loc are.
then maybe ground them to the hu

 

[Cr@sh]

would a high power loc degrade quality? i heard that only the expensive ones dont.
im trying to keep this as cheap as possible too.
i think im going to rewire the loc's from right behind the hu and run rca's to the amp instead of running the speaker wires to the amp where the loc are.
then maybe ground them to the hu

Your current LOC's may be the issue with all the noise. I would consider THESE. I mean short of buying a new head-unit that has at least 2-5v pre-outs to drive the signal to your amps the stinger converters would be cheaper. Yes I would run that at the radio with no speaker connected. Just radio to LOC and rca to amp.

 

[majorahole]

the thing is, the amp inputs are not adjustable. it is rated for 0.775v.
my calculations(if they are right) sow that right now im and just over 1v, so that may be a bit of the problem, but def not all of it. i have a pair of 10k stereo pots coming to see if thats the case.

 

[Perry Babin]

The volume of the head unit determines the voltage the amp receives.

 

[majorahole]

yes, but i think its maxing out early in the volume turn

 

[Perry Babin]

You can fade away from the outputs being used to decrease the level of the signal from the head unit.

 

[Cr@sh]

What amp is it?

 

[majorahole]

im using both front and rears, 2 loc's.
it is the sure 4x100w t-amp board
here is the pe page
Sure 4x100W @ 4 Ohm TK2050 Class-D Audio Amplifier Board
here is pdf info and schematics
http://www.parts-express.com/pdf/320-302m.pdf

 

[Cr@sh]

In post #3 it say's you have a direct ground for this amp running to your battery correct? If so have to tried grounding less then 18" right to the body? It would be easy to do.

 

[majorahole]

In post #3 it say's you have a direct ground for this amp running to your battery correct? If so have to tried grounding less then 18" right to the body? It would be easy to do.

that was just for troubleshooting purposes. its at a factory ground point about 2.5' away

 

[Cr@sh]

that was just for troubleshooting purposes. its at a factory ground point about 2.5' away

When you say "Factory" can be more specific? or show a pic?

 

[majorahole]

Its a spot where the car had a ground already. Others have used the same one without a problem

 

[majorahole]

well i re-did the front loc from right at the back of the head unit, hoping to get less noise but its still there. im gonna try to reground the amp to the seat bolt tonight, if i can find time. havent bothered with the pots yet. dont think they will change the noise at all.
if i have time i might try to make a choke-capacitor filter out of some old computer psu parts. dont think i have a large enough cap handy tho.

 

[Perry Babin]

All of this is probably a waste of time unless you use LOCs with internal transformers or external ground loop isolators with the LOCs you have.

One other thing that 'may' help is grounding the amp at the same point as the head unit.

 

[Cr@sh]

I know for fact that I have used crappy loc's they caused nothing but noise. I would use something like THIS or THIS

 

[majorahole]

OK, so im pretty sure this hu is not normal. I decided to disconnect the negative on one of the loc inputs, and it still plays through the amp? I'm pretty sure that's not normal, but there is still noise.

 

[majorahole]

OK, i think this hu has active balanced outputs which isn't a huge deal, but if i use a different source with the same result doesn't that mean it isn't the loc or hu?
I'm going to try and make a filter for the power line. Will an RC filter do? Or an LC? Which should i try?

 

[majorahole]

well i ended up getting a P.A.C. SOEM-4 to solve my problem. i guess the hu was either balanced/differential, or 4 wire common ground. i used my vag-com and programmed it for low level output and it sounded much better as far as the quality, but the whine and buzz were worse when the car was on. so i put the loc in there to convert to a normal single ended signal. now i have very very little buzz from the rear speakers only, and very very faint whine. you cant hear the buzz with the car running, and you can only hear the whine if the volume is all the way down. first notch up and its drowned out. im pretty sure both issues are from my extra cheap rca's i used for my rear input.

 

[2500hd]

Is this amp's power adjustable at all, or is it just wide open all the time?