Help - power but no sound

Posted by: furtive

Help - power but no sound - 21/11/2005 12:27

I've installed a cheap CD head unit to keep my going whilst my empeg is being repaired but I'm having trouble with it.

I get power ok, and am able to tune the radio in, but I don't get any sound from my speakers.

I have an amp in the boot and forward and rear speakers. I've tried plugging the pre-out into either set of RCA plugs leaving the other pair loose. No sound anywhere.

When I removed the empeg sled I noticed that there was a blue wire coming from the direction of my amp. It had a bullet connector that conneced onto a blue wire on the empeg loom. Any idea what this is, and could it be causing the problem?

What else could be the issue? A blown fuse somewhere? If the speakers were shorting out somewhere, could this cause an issue?

Any suggestions would be appreciated.

Or should I just GAMI?
Posted by: pgrzelak

Re: Help - power but no sound - 21/11/2005 12:29

Blue? Is that the amp remote line??? If so, that will certainly need to be connected.
Posted by: furtive

Re: Help - power but no sound - 21/11/2005 12:31

Thanks.

Connected to what?
Posted by: pgrzelak

Re: Help - power but no sound - 21/11/2005 12:51

Assuming your empeg is going into an input line on the other head unit, it should connect to that head unit. If you are going from the other radio to the aux in on the empeg, it should connect to the empeg.

Basically, if it is what I think it is, the blue line you see is the amp remote line - the wire that (when 12v is applied to it) signals the amp to turn on and do its thing. It might be that everything else is correct, but the amp (not seeing the remote signal) is turned off. Do you have a status LED or any blinkenlights on the amp to show that it is turned on? (Note: This is completely different from the amp's power feed, but you probably already know that.)
Posted by: JBjorgen

Re: Help - power but no sound - 21/11/2005 12:56

There should be an amp remote wire on the head unit also. Just connect it to that.

I know this sounds stupid, but it's gotten me a couple times. Remember that the AC and DC volume settings are separate, so you shouldn't assume that just because you can hear music in the house, that the volume is set properly in the vehicle. You'll want to move it from -infinity to 0db when you have it running into the aux input of another head unit.
Posted by: furtive

Re: Help - power but no sound - 21/11/2005 13:00

Whoh there. I don't have a working empeg. I have therefore removed my empeg sled and loom and am plugging this new headunit into the ISO plug instead.

I didn't see an amp wire coming out of the headunit. Just a bunch of wires going into an ISO plug.

I guess I just need to test each of the (blue) wires coming out of the ISO plug until I find one that has 12v on it with the headunit turned on and 0v with it turned off, then just connect that wire to the loose blue one? Sounds easy enough.

Right, question 2 - I have a 4 channel amp so have 2 pairs of RCA connectors but the headunit only has a single pair. Can I just get one of these and join the front and rear's together?

Posted by: JBjorgen

Re: Help - power but no sound - 21/11/2005 13:08

Quote:
Whoh there. I don't have a working empeg.


Oh. Right. I went back and read the beginning of the thread. I forgot about that.

You should be able to consult the manual that came with the head unit and find which of the wires is the amp remote. Then just remove that wire from the ISO plug or clip it (far enought back that you can reconnect it for future use) and connect it to the blue amp remote wire heading toward your amp.

IIRC, if you split the RCA, you'll lose some volume (level voltage), but as long as you have enough power in your amplifier to compensate, I think it should be ok.
Posted by: furtive

Re: Help - power but no sound - 21/11/2005 13:14

Thanks.

Unfortunately the "manual" for the headunit is sparce to say the least. The installation guide says "plug in the connector". I guess you get what you pay for. It looks pretty though.

Amp should be more than powerful enough - it's one of these:

http://www.caraudiodirect.co.uk/product_...42aa1a5d26f0b27
Posted by: pgrzelak

Re: Help - power but no sound - 21/11/2005 13:25

What kind of cheap CD head unit? Does it have an "amp remote" line or equivalent?

I found a PDF of the genesis profile four. The last connection at the very end is labeled as the remote line. Your blue wire should probably be connected to this line on the amp, and to the "remote" wire output on your head unit (if one exists).
Posted by: furtive

Re: Help - power but no sound - 21/11/2005 13:30

This type of cheap headunit.
Posted by: pgrzelak

Re: Help - power but no sound - 21/11/2005 13:44

Hmmm... The head unit's site seems to say it uses an ISO out adapter. It might be that it uses the same position in the ISO adapter that the empeg uses (pin 5 in the wiring diagram). Still looking...

Edit: Aha! Over on their support FAQ page, they answer about connecting the amp remote out line with:

Quote:
Where can I connect the remote wire of my amplifier?
If you are using an after market radio you would connect the remote of the amplifier to the remote wire of the radio labeled; (remote, amp turnon or pwr. ant) on most radios a blue wire or on others a blue with a white tracer. If you are interfacing the amplifier with a factory (OEM) radio you will connect the remote terminal to an accessory wire that powers up only when the key is in the on position.
Posted by: furtive

Re: Help - power but no sound - 21/11/2005 14:40

Ah ok, thanks. All I need to do is take the wire from pin 5 and connect it to my amp remote wire and everything should be good to go. I'll give it a go.

How on earth did you find that FAQ on their website? I couldn't find it anywhere - just a load of word documents in Chinese!
Posted by: pgrzelak

Re: Help - power but no sound - 21/11/2005 15:55

Greetings!

I think that will work, assuming their ISO connector is standard (not a certainty), but there should be some labeling on the head unit.

As for the PDF and information, I found myself in the support section after a few googles, and was able to get to their FAQ page. That is what I linked. I hope it will help.
Posted by: tfabris

Re: Help - power but no sound - 21/11/2005 16:44

Quote:
Right, question 2 - I have a 4 channel amp so have 2 pairs of RCA connectors but the headunit only has a single pair. Can I just get one of these and join the front and rear's together?


Depends on the direction you're going. I think, assuming that what you're talking about is a 4-channel amp and a 2-channel head unit, yes that's possible.

But you're not joining in that case, you're splitting. So your word "join" is confusing there. What you'd be doing in that case is splitting the outputs of the head unit to go into the 4 inputs of the amp.

However. does your amp have pass-through connectors on it? If so, use those instead, do not use the Y-splitter adapter you pictured. Only use the Y-adapter as a last resort if your amp doesn't have pass-through connectors. Illustrations of various ways to hook things up are here.

If you're going the other direction, trying to take four output channels and combine them into two input channels, that really is joining, and you should not do it.
Posted by: JBjorgen

Re: Help - power but no sound - 21/11/2005 16:52

According to the Genesis Profile Four amplifier PDF Paul linked above:
Quote:
1. If only one set of pre-outs are available plug these Into Inputs 1&2. Signal will be fed to Inputs 3&4 Internally. Do not use 'Y' cables.
Posted by: matthew_k

Re: Help - power but no sound - 21/11/2005 17:08

To make sure it's the amp remote wire, use a little jumper wire from the amp's power line to the amp remote input. Then turn on your new HU and see it it works.

Then you'll know you're solving the right problem.

Matthew
Posted by: tfabris

Re: Help - power but no sound - 21/11/2005 17:31

Yeah, just don't hook it up that way permanently, or you'll get speaker-damaging pops when you turn the car on and off.
Posted by: tfabris

Re: Help - power but no sound - 21/11/2005 17:31

And yeah, what Meatballman said.
Posted by: furtive

Re: Help - power but no sound - 23/11/2005 12:33

Many thanks for everyones advice.

I popped home at lunchtime today, ripped the dash apart again andset to work.

I cut the blue wire coming out of the headunit loom (as if defusing a bomb movie-style) and crimped the two ends back together in a female bullet connector so that I could then plug inthe male bullet connector coming from my amp.

I now have sound from the front speakers.

For some reason though, nothing from the rears despite connecting it up as per the Genesis instructions. I tried plugging the rear RCA's into the headunit and got sound, but nothing when trying to get the amp to automagically sort things out. Any ideas why?

Anyway, front speakers working is better than no speakers working
Posted by: pgrzelak

Re: Help - power but no sound - 23/11/2005 13:10

Okay. Progress!

Now, you are not getting anything out of the rear speakers? Except when you plug the rear RCAs into the front head unit outputs? Do you have the fader controls set correctly? Another thought, make sure (if you are not using a sub) to have the lowpass filter off on the amp. Are you using Y cables? Can you clarify your existing wiring and options on the head unit? Thanks.
Posted by: furtive

Re: Help - power but no sound - 23/11/2005 13:19

Right, looking again at the wiring diagram for my amp it shows that the front preouts are on the far left - but these are the ones I have removed as they were driving the rear speakers!

So it looks like when my amp was installed the wiring was done incorrectly. So if I move the connections from the right hand connectors to the left ones, I should be good to go I think.

If you can excuse my poor MS Paint skills, the attachment shows roughly how it's all wired up.
Posted by: pgrzelak

Re: Help - power but no sound - 23/11/2005 13:41

That should do it! It looks like you should have a nice setup when you are done. Cool!
Posted by: mtempsch

Re: Help - power but no sound - 23/11/2005 13:49

Quote:
Right, looking again at the wiring diagram for my amp it shows that the front preouts are on the far left - but these are the ones I have removed as they were driving the rear speakers!

So it looks like when my amp was installed the wiring was done incorrectly. So if I move the connections from the right hand connectors to the left ones, I should be good to go I think.



What's front and channels on an amp is typically not set in stone, but which signal (front/rear left/right) you plug in where on the amp. Though often you're constrained by what filter options are available for what channels on the amp and how you typically set up a system (front system HP filtered to reduce the stress from deep bass, rear channels LP filtered to run a sub ). The labelling on the amp should [hopefully] be consistent between input and related output, but you're of course free to ignore any 'front', 'rear', 'left', 'right' labels if it better suits your setup - cable runs, filtering etc...
Quote:

If you can excuse my poor MS Paint skills, the attachment shows roughly how it's all wired up.


Hmm, as I interpret that, you're running everything off the HU and the amp actually doesn't power anything at all... And you've got two speakers in parallell on each channel in the rear, possibly creating a too low impedance for the HU, but yhat's not the impression I got from the posts earlier in the thread...
Posted by: wfaulk

Re: Help - power but no sound - 23/11/2005 14:00

Yeah, but John already posted a snippet from the manual for the amp that said that if something is plugged into the front inputs but not the back, then the amp would send the signal to all four speakers. In that case, it does make a difference.
Posted by: furtive

Re: Help - power but no sound - 23/11/2005 14:04

Quote:
Hmm, as I interpret that, you're running everything off the HU and the amp actually doesn't power anything at all... And you've got two speakers in parallell on each channel in the rear, possibly creating a too low impedance for the HU, but yhat's not the impression I got from the posts earlier in the thread...


Oppsies - my bad. All the dirty yellow squiggly lines should be going to the amp, not the headunit.
Posted by: mtempsch

Re: Help - power but no sound - 23/11/2005 14:47

Quote:
the front inputs but not the back, then the amp would send the signal to all four speakers. In that case, it does make a difference.


Ah, yes - overlooked that...
Posted by: furtive

Re: Help - power but no sound - 25/11/2005 11:49

Right, many thanks guys. Just popped home and fixed it. Swapped the cables over so they were plugged into the right ports on the amp, and also un-pressed a little button that should have been out according to the amp instructions and I now have glorious sound coming from all 8 speakers

The headunit seems to forget it's settings every time I turn off the ignition, but looking at the comments on the site I bought it from that looks like a common fault caused by incorrect loom wiring - just need to swap the red and yellow cables over I think.
Posted by: pgrzelak

Re: Help - power but no sound - 25/11/2005 11:54

Excellent!!!
Posted by: furtive

Re: Help - power but no sound - 04/12/2005 10:21

Erp! It's stopped working!

It worked fine for a couple of days and now no sound again

I've had the dash apart and have recrimped the connection - it's definitely good. So what else could be causing a lack of sound? I've no idea if the amp is powering on or not - there doesn't seem to be a way to check, but I'm guessing it's not.

I tried to check for some sort of voltage on the blue wire when turning the headunit on, and there didn't seem to be anything coming from it at all.
Posted by: pgrzelak

Re: Help - power but no sound - 04/12/2005 11:06

Have you checked the player on AC power, just to be certain it is not the empeg itself?
Posted by: furtive

Re: Help - power but no sound - 04/12/2005 12:30

I'm not using my empeg as it's currently broken - this is a cheap replacement headunit.
Posted by: pgrzelak

Re: Help - power but no sound - 04/12/2005 15:21

Oh, yeah. Sorry - I forgot...

Can you plug another line level device into the input of your amp and see if it generates audio?
Posted by: mtempsch

Re: Help - power but no sound - 04/12/2005 16:18

Quote:
I've had the dash apart and have recrimped the connection - it's definitely good. So what else could be causing a lack of sound?

Lack of power to the amp, no turn on signal (emote) to the amp, no audio signal to the amp.

Quote:
I've no idea if the amp is powering on or not - there doesn't seem to be a way to check, but I'm guessing it's not.

I tried to check for some sort of voltage on the blue wire when turning the headunit on, and there didn't seem to be anything coming from it at all.


Sounds like the HU remote out is broken... but let's check the basics:

Power: Take a voltmeter and measure across the power supply terminals (B+ and Ground) and make sure you've got 12V there - if not, check power wires, fuse(s) and ground attachments.

Remote: With HU on, measure across the remote terminal and ground on the amp. If not 12V there the amp will not turn on. If there isn't, try disconnecting the remote wire from the amp (insulate it just in case) and temporarily connect the remote terminal to the B+ terminal (should turn the amp on permanently, so don't leave it like that after testing). You could also try measuring between the remote wire and ground (both on the radio and back by the amp) with the wire disconnected from the amp, just in case the amp is broken and pulls the voltage down to ground. You could also check continuity/resistance between the remote wire and ground (so it's not cut through and grounding out somewhere)

Audio signal: If the above doesn't give you sound, try another signal source, like a portable player with adapter cable (3.5mm to RCA).
Posted by: furtive

Re: Help - power but no sound - 31/12/2005 11:11

Finally got round to taking a look at this.

There was a big 60a fuse between the car battery and the amp that had blown. I think water had got into it as the end cap wasn't on properly and my boot can get pretty damp.

Anyway, replaced the fuse (and the end cap properly) and it's all working now.

Thanks for all your advice.
Posted by: tman

Re: Help - power but no sound - 01/01/2006 14:48

Huh? Getting a fuse wet shouldn't make it blow. Good that you managed to fix it tho.
Posted by: furtive

Re: Help - power but no sound - 01/01/2006 16:05

It might make it corrode though...
Posted by: furtive

Re: Help - power but no sound - 03/01/2006 09:10

One thing I have noticed though is I get sound from the rear speakers only if the low-pass filter on the amp is turned off.

If I turn it on, I get sound from the front speakers too but it seem to be low frequencies only.

So, anyone know how I setup an amp? The amp has got several buttons and knobs on the back, but I don't know what they do, and the "instructions" for the amp aren't much help either:

Link to amp instructions (PDF)
Posted by: StigOE

Re: Help - power but no sound - 03/01/2006 10:24

How is it connected?

If you turn on the HP filter, you will only get what's meant for subs from channels 3&4, so it should be off.

What's the fader on the Empeg set to? You haven't by any chance set it to rear out only?

Basically, it should be connected as in the first example...

Stig
Posted by: furtive

Re: Help - power but no sound - 03/01/2006 10:28

empeg is broken so I'm using a cheap HU with only one pair of outputs. The amp should automatically route the sound to all speakers but for some reason only routes to the rears unless I turn the filter on. Not sure why it's going to the rears and not the fronts to be honest. Could the amp have some sort of bias setting or something?
Posted by: StigOE

Re: Help - power but no sound - 04/01/2006 01:05

Right, you probably said that in one of the first posts in this thread...

If the signal is going in to channels 1&2, then it should be sent internally to channels 3&4, or so the manual says, so make sure you're using channels 1&2. If still no sound, try to adjust the gain(level) on channels 3&4. If you still don't get any sound, I'd say it looks like the amp is broken...

Stig
Posted by: furtive

Re: Help - power but no sound - 06/01/2006 13:31

Quote:
If still no sound, try to adjust the gain(level) on channels 3&4.


I assume that means twiddle the knob on the amp to see if that makes any difference?
Posted by: StigOE

Re: Help - power but no sound - 07/01/2006 03:27

Quote:
I assume that means twiddle the knob on the amp to see if that makes any difference?

Yes.

Stig
Posted by: furtive

Re: Help - power but no sound - 08/01/2006 09:37

Knob twiddling has done the trick. I've now got sound from all 8 speakers
Posted by: StigOE

Re: Help - power but no sound - 08/01/2006 10:55

That's good. Glad you got it sorted.

Stig