I got my empeg installed in a 2000 Isuzu Rodeo.

The only problem I'm having is that using the brakes (because of the brake lights), wipers, etc... sometimes will produce some small pops and clicks thru the speakers.

I took the car back once to have them check all the grounding and, while they got it a little better, it still does it.

The installer is blaming the device, saying that as far as he knows he's done everything he could.

Any insight on how likely the empeg is to blame or how likely the guy doesn't know what he's talking about?

-D

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reg. #10798 - blue 40gig MK2 #764

I've had this happen on some systems. It is correctable.

It is definitely a grounding/filtering issue. Go to the FAQ section of this BBS and locate the message about "What are the most common installation problems?". You will find links to some PDF documents to help you trace the fault.

Remember that the Empeg is not the component responsible for producing the sound. It is the amplifier(s). To take care of noise problems, you must look at the system as a whole, not just the Empeg.

By any chance, is your amp a cheap-o model, or is it a nice one?

___________
Tony Fabris

I'm afraid it might fall into the cheap-o-model category since I only wanted to drive the factory speakers with it.

It's a kenwood amp which I think I paid $399 for, although I should check again because I might not remember correctly.

Should I consider investing more into the amp to make those little problems go away or go and bug my installer some more?

-D

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reg. #10798 - blue 40gig MK2 #764

I'd bug the installer...

I've got 2 really cheapo (less than US$100) Pyramid amps, one 4ch
running stock front components (VW Polo '01) and 8" 3ways at the rear
and a 2ch running a 12" sub. No clicks or pops at all.

I'd look at how the amp is supplied with power, how/where it is
grounded and how the signal cables are routed...

/Michael

A 399.00 amplifier is definitely not a cheap-o amp. So look at those PDF documents and see what you can come up with.

Some things to consider:

- Audio cables and power cables run seperately?
- Empeg and amps connected directly to battery rather than through the car's memory wire?
- Amp gains tuned properly?

___________
Tony Fabris

I had some similar noises after my initial install. They're likely to happen anywhere the signal (RCA) lines between the empeg and amp get near to the vehicle's wiring. I cleared mine up simply by rearranging the rat's nest of wires behind the empeg keeping the power wires on one side and the signal wires on the other. There are also RCA cables built specifically for in-car use that have better shielding, you may want to try these.
Also, as a rule of thumb, don't run power and signal wires to your amp via the same route. You're almost certain to get noise that way.

-Zeke

just say you weren't paying much attention...

Maybe I'm remembering the price wrong...

All I'm sure of is that it was over $200 but that it was the cheapest they had (it's a 4x25W).

I guess I'm off to do some more bugging next week-end... :o)

Thanks,
-D

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reg. #10798 - blue 40gig MK2 #764

If you get a click when you take your foot off the brake pedal, then I would suspect that your amp is not properly suppressed. Releasing an inductive load in a car causes a power line spike. Does it have a power line filter?

I have also found on a number of occasions with radios that if the unit is poorly earthed, the unit becomes sensitive to power line (and any other) noise (alternator, switches, wiper motors, etc.). This is due to a high-impedance return path from the unit to the chassis.

I'd check the earthing of the empeg and the amps, which should be earthed with individual lines to one point only; the line wire thickness should be sufficient to handle 50% over peak load from the device (I'm sure tanstaafl will be able to advise better on wire thickness here). Finally, both the amp and the empeg should have their own power line supressors of the correct continuous current rating; if you (for example) use just the empeg's choke for both amp and empeg, then the normal current drawn by the units will cause the core to saturate and reduce the suppression of transients.

One of the few remaining Mk1 owners... #00015

It turns out the amp was $180 (I checked last night).

Does that qualify as cheap-o?

-D

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reg. #10798 - blue 40gig MK2 #764

Thanks for the detailed info, I'm taking a printout of your post with me when I go back!

Just so that I have extra ammunition for my next showdown with the installer:

Am I correct in thinking that if the pop was coming from the empeg's shielding it would very likely be amplified by the amplifier?

What I mean by this is that the pop's loundness is independent of volume setting on the empeg or gain setting on the amp, so that if the empeg is playing loud enough I can't hear the pop at all.

Wouldn't that indicate something between the amp and the speakers?

-D

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reg. #10798 - blue 40gig MK2 #764

Wouldn't that indicate something between the amp and the speakers?

Not necessarily.

Noise problems, especially when caused by grounding issues, can be caused anywhere along the power/signal chains. You really have to examine the whole system carefully, step by step.

Did you print out those PDF documents about noise? Those are very useful and accurate, and would be great ammunition to give to your installer. One of them has a very specific diagram of how to use a relay to get rid of exactly those sorts of pops.

___________
Tony Fabris

Is it the Kenwood KAC648S?

If so, then no, that doesn't qualify as cheap-o. That amplifier should be fine. There are about a dozen other reasons you could be getting pops and noise in the system. Print out these documents for more information:

http://www.installdr.com/TechDocs/999501.pdf
http://www.installdr.com/TechDocs/999502.pdf
http://www.audiocontrol.com/techpapers/tech1002.pdf

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Tony Fabris

Yeah I printed all that AND the faq and will make sure to put this in front of their nose.

With regard to my question, I guess I was just assuming that if noise gets in before the amp then the amp would amplify the noise too.

-D


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reg. #10798 - blue 40gig MK2 #764

With regard to my question, I guess I was just assuming that if noise gets in before the amp then the amp would amplify the noise too.

Well, yeah, sort of. But you have to understand how ground loops work to see that it's not really a question of where the "noise is getting in". The entire signal chain is kind of like one entity. The power going to the amplifier is indirectly connected to the signal cables, which is indirectly connected to the empeg's circuitry, which is indirectly connected to the empeg's power source. Ground loops occur when the resistance to the grounds at each point varies, causing voltage from the power supplies to leak into the signal chain, hence the pops you're hearing.

And as far as inductive noise is concerned, those signal cables are like a big antenna, picking up whatever's going on around them...

___________
Tony Fabris

Imagine you have a high impedance ground to the amp, the amp is powered on and stable, and it is drawing a given curent. There is a stable, low-voltage level at the input to the amp (the empeg is paused). You now press and release the brake pedal. When you release, you get an inductive EMF in the power line (a small one, since it's only a light bulb or two). The amp should allow the spike to pass if it's got on board RF supression, but the high impedance earth return means that the earth voltage rises with the spike in the power line. Relative to the input level, that is a step voltage seen at the input stage of the amplifier. If you have high gain on the amp, POP. I would get the guy at the shop to look at the earth point voltage of your amp, compare it to the DC ground for the amp (if they need to be seperate) and then have a look at what it does when you release the brake pedal. You will need a high impedance scope to do this.


One of the few remaining Mk1 owners... #00015