Inconsistent sound output from Sony Xplod HU

wonderloaf · Post by **wonderloaf** » Fri 13 Aug, 2010 11:37

Hi all, have problem with my HU that I hope you can help me with, it's driving me crazy!

A couple of days ago swapped my BMW Business HU (the one with the Tape deck) for a Sony Xplod CD/Radio HU. I like the Sony because it has a USB and Aux input on the front. Used an adapter lead from fleabay to hook up the new HU, then tested the output on all speakers for Radio/USB/CD and all was good, getting sound where expected, all speakers working OK.

Next day got in the zed to go work, turned on the HU and the radio was OK, but as soon as switching to USB/CD there was no sound from the front footwell speakers; front tweeters and rear speakers are OK (actually think the rear speakers were a bit louder than previous). Switching back to radio and all was well again, but as soon as switching to USB/CD lost sound from the footwell speakers.

So got home that night, pulled out the Sony and swapped back to the BMW HU. All OK from the Radio and CD (Disc Changer in the boot). Checked the pinouts on the adapter lead all OK. Re-installed the Sony, sound from all speakers as expected. Went for a drive for an hour or so and sound from the speakers was OK on Radio/CD/USB. Left it to see what would happen the next day.

So next day got in the car to go work and lo and behold, the old problem is back...sound is OK on all speakers from the Radio, but front tweeters and rear speakers only on CD/USB. Just checked again about 20 minutes ago and still no sound from footwell speakers.

I'm not sure what's happening here, I can't understand why the speaker output should be different depending on the source, as it all goes through the HU.

Anybody got any ideas on my next step (without re-installing the BMW HU or buying a new HU!).

Car spec: 2001 2.2 Sport with BMW Business Radio/ Tape + 6 CD changer in the boot.

Any help gratefully appreciated, wonderloaf

Post by **Robert T** » Fri 13 Aug, 2010 11:45

Well the switching on/off of the footwell speakers sounds like the classic remote control wire which turns the amp in the footwell speakers on and off... but that doesn't explain why this changes when you switch source... unless the remote control wire is connected to the wrong output from the HU.

If you have no joy in sorting out which wire needs to be connected to which, then it may just be easier to bypass the amp completely - there is a thread on here with pics of how to do it.

On my Pioneer HU I found I had no sound from the footwell speakers and just had to go back in and connect the remote control wire - it had a free bullet connector on it - I had forgotten this when I changed the adapter cable over to the new one.

Still not sure why swapping the HU back and forth would turn the amp on for all sources - I don't think there is any kind of latch in the circuit.

Cheers R.

TaffZee · Post by **TaffZee** » Fri 13 Aug, 2010 12:04

I think this sounds a bit as if a circuit protection system is kicking in. All amps have protection, I think you may well be overdriving the speakers? which is cutting the power from the amp.

Jonttt · Post by **Jonttt** » Fri 13 Aug, 2010 14:47

Too much Meat loaf playing

wonderloaf · Post by **wonderloaf** » Fri 13 Aug, 2010 16:11

Jonttt wrote:Too much Meat loaf playing

Is this ever going to end?...

..probably not

wonderloaf · Post by **wonderloaf** » Fri 13 Aug, 2010 16:49

OK, back to business:

Got in the zed tonight, still no sound from footwell - so no good
Got home, left the car alone for half an hour, tried again - no good.
Pulled the Sony HU out of dash, ignition on - no good
Ignition off, remove the 2 ISO connectors, replace ISO's, ignition on - no good.
Ignition off and on, remove power ISO only and replace - no good.
Remove and replace the speaker set ISO only - SOUND OK!
Tried to replicate no good sound - can't do it even if I really pump up the volume.

As Taffzee says, seems like it's something to do with the speakers protection

@Robert T: I did see a mention of the amp remote on another forum, but apparently the power cable for the electric antenna does the same thing, and that is included in the standard wiring harness, so need to use the seperate amp remote.

Looks like I'll be trying to bypass the speaker amp then..unless anybody has got any other ideas before I start pulling my beautiful new(ish) zed apart? Have any other Sony users encountered the same problem?

Tufarlian · Post by **Tufarlian** » Fri 13 Aug, 2010 17:13

wonderloaf wrote:.... apparently the power cable for the electric antenna does the same thing, and that is included in the standard wiring harness, so need to use the seperate amp remote.

Unless the Sony HU is being clever and putting power on the electric antenna feed only for radio, not for CD playing.....

wonderloaf · Post by **wonderloaf** » Fri 13 Aug, 2010 17:45

Tufarlian, you must have read my mind, thinking exactly the same thing. So just been out to the zed and spliced the amp remote lead from the HU into the amp remote connection of the BMW connector via the adapter lead. All seems to be well, but been here before..

If the Sony HU is only putting power down the antenna feed for playing the radio, then as you switched to and from the radio presumably the electric aerial would keep going up and down! Not a cool look!

Anyway it was easy to do only 5 minutes work, so I'll see what happens tomorrow and report back.

If it doesn't work then I guess I'll have to bypass the amp, and seeing as I'm down removing the speaker anyway may as well put an upgrade set in...and so it starts...

Tufarlian · Post by **Tufarlian** » Fri 13 Aug, 2010 18:33

Bet it'll be fine now.

wonderloaf · Post by **wonderloaf** » Sat 14 Aug, 2010 07:58

Just been out to check the zed, all seems fine now, so seems it was the amp remote after all.

Chalk up another success for zroadster.net, thanks for all your help.

Tufarlian · Post by **Tufarlian** » Sat 14 Aug, 2010 08:09

Good. Glad it's ok now.