Just purchased new head unit and having issues....

[VQXTC]

Hi there all....

Just purchased the Sony CDXR 5810, the problem I am having is my speakers are cutting out at high volume.....

The Sony unit replaces a sanyo unit, with the sanyo unit I had no problems at all.....

However with the sony unit I turn the volume up above 25 and when the bass comes through from the sub keeps going but the speakers cut out.....

Everything is running off amps....very frustrating considering it was all working fine before i changed the unit......

Any help will be greatly appreciated......cheers

[jack.mc]

Could it be a "speaker protecting" mechanism?

[azzfox]

not sure caus your using amps but i have had this prob before and it was the head units earth. did you earth it to chassis or original wiring harness?

[semi]

might want to check your RCA connections at the back of the HU

[nizmovk]

some had desks have separate output volumes, ie: front/rear/RCA etc... you may just need to adjust these or amp volumes..

[nizmovk]

...decks...

[shaggerz]

sounds a lot like the amp driving the speakers is going into protection mode. This could be due to thermal overload (its getting too hot) or voltage drop. Voltage drop is probably more likely and could be due to a bad earth or wiring being too thin. Much more likely to be a bad earth.

I have also seen this occur when the impedance of the load on the amp was too low. This causes the amp to go into protection mode at high volume.

[mouce]

When you replaced the head unit, did you retune the amps? The gain settings will most likely need to be changed to get them to run properly. It sounds like you're driving the speakers way past their limits, and the amps are shutting them down to prevent blowing them up.

Just a thought.

[garfa]

When you replaced the head unit, did you retune the amps? The gain settings will most likely need to be changed to get them to run properly. It sounds like you're driving the speakers way past their limits, and the amps are shutting them down to prevent blowing them up.

Just a thought.

to expand was the h/u replaced a 4V preout and the sony a 2V preout?
here should not be a huge difference in the strength of the h/u rca signal, not enough to make the amp go into protection mode unless you had set your gains at their very limits.

[shaggerz]

to expand was the h/u replaced a 4V preout and the sony a 2V preout?
here should not be a huge difference in the strength of the h/u rca signal, not enough to make the amp go into protection mode unless you had set your gains at their very limits.

I didnt think that clipping on the preamp side of an amp could cause it to go into protection mode. I was under the impression that only a problem with the power supply or the output stage could cause this? I may be wrong though

[semi]

what he means is that if the input of your amp gets higher, the signal that the amp puts out will also be higher. But what garfa is saying is that the difference between the two HU's will be very minimal, so probably wont cause it

[semi]

Im thinking maybe a poor earth on the HU side of the RCA's. But just a guess really

[garfa]

what he means is that if the input of your amp gets higher, the signal that the amp puts out will also be higher. But what garfa is saying is that the difference between the two HU's will be very minimal, so probably wont cause it

thanks, took the words right out of my mouth.
also yes clipping on the input of an amp, if it is running near its limits can make it go into protection. when a amp or preamp clips it will have a hugely enlarged signal, therefore if the input signal is 10 times bigger the output can be huge!
but semi understood what i was getting at.

[VQXTC]

Thanx guys for the replies......

I retuned the amps last night....sounds good when the sub amp is d/c.....however when I reconnect the sub amp and start to adjust the gains. The speakers cut out as soon as there is a decent bass note.....

I checked the earths to both the amps and they are fine.....

However I did notice one thing though I am only using 8 gauge cable from the battery to both amps (the 8 gauge cable was done before i put the second amp in) and one of those amps is a monoblock.....I think this maybe the cause of my problem, what confuses me is that there wasnt a problem before the sony unit went in......

When I checked it with the multimeter and the headlights on, heater etc the battery voltage was 13.4V DC. At the amps at full volume the amps are seeing b/n 13.0V DC and 11.8V DC......

The only other thing I can think of is that the sony unit has a higher voltage on the RCA's than the sanyo. Although with a tune this shouldnt make that much of a difference.......


This is really frustrating....everyday I sort other peoples problems out, yet I cant sort my own one out.....

Oh and my misses is not making things easy....

[diagonal sleeper]

i had this very prob when i first bought my car. it didnt have enought output amp wise (must've taken the good one out the prick!) so i put in a cheapo boss amp, heaps of power- but it hatted the kenwood hu.
it did EXACTLY as you described, with no logical expanation at all! I stuffed around with everything on the list, ended up swapping hu with a cheepy and it worked, except the quality, as one would expect of cheep stuff, was up to s**t! so i flogged it for a while, and guess what? it fried!
so i chucked the amp and hu and just put another kenwood amp in beside the other. never had a prob since.
i have no explanation for what happened to me. but the amp i used was at fault.
try changing the impendance load on amp to see what happens. i.e. dont bridge it or load it up any lower then 4ohms. if it runs without cuting out, it could be that the amp cant sustain 2ohm loads without 'protecting' itself

[Phreddy]

Definitely go a heavier cable XTC - 8G is OK if you're running one amplifier, but won't be doing either of 'em any favours once you connect a second one.

I agree with the input overdrive type scenarios pointed out above (garfa, shagz, semi...) or even possibly a protection mechanism of some sort, but the power feed needs to be beefed up.

Run 4G at least, or even 2G if the amps are higher than average power. Also, make 100% certain that both the ground AND Batt+ connections are CLEAN and TIGHT at both the amp AND the battery/ground point - also check the condition of the connections in and out of your fuse. (you HAVE fitted a fuse to the main power feed, right??) Wherever terminals attach, inspect these as well for corrosion or otherwise flaky connections. Once you're happy that it's not a power issue, that eliminates that as a possibility, and you can get on with tracking the problem down if it still exists.

Cheerz Mate - still gotta build that sub box too, but I'll let you know. All the best with it...

[diagonal sleeper]

it sounds like power. what amp config are you running? how is the power split? how are they earthed? ie do 2 amps have 2 sperate earths at 2 different points on the car?alternator output? lowest voltage with all accessories, bar the stereo ,running? if i were you i would beef up my wiring just for the sake of it, including alternator, all power and earthing points under the hood, and a direct earth from alternator the chassis- which car designers seem to overlook. just a thought

[garfa]

well yes 8ga would make the amps go in to low voltage protection.
whats the total RMS of both amp combined. eg 300Wrms monoblock and 60Wx4 so a total of 540wrms.

[Tasmaniak]

Try to see if your headunit has a low filter that can be used on the speaker outputs.

MY thoughts are something in the headunit....not the amp.

Defeinetly upgrade the power cable. To 4ga.