Guys,
I changed the value of the 3.3V reference divider and now the Empeg runs to a lower voltage before it signals the processor. The battery icon was never the problem, just the audio cutting out. It now seems to run down to @ 10.0V or so before reporting low voltage. This will help me greatly. The biggest problem with the op amp signalling circuit is that it has almost no hysteresis, therefore it senses low battery, cuts out, comes back on, then the voltage rises slightly and the icon goes away. Then with a good bass note or even pushing a front panel button the voltage dips again and the condition repeats. So in other words, just listening, the Empeg can cut out several times a minute if the battery is sitting on the 10.5V threshold. With the divider modification it will still cut in and out multiple times but just at a lower overall voltage which will be just fine for me.

Thanks for all the help.

Nick

It now seems to run down to @ 10.0V or so before reporting low voltage.

But isn't this along the lines of getting a bigger can to bail out your leaking rowboat, instead of fixing the leak?

There should be no circumstance (except maybe when actually starting the engine) that your voltage drops much below 12 volts. You have a problem in your car's electrical system (specifically in the charging circuit) that you need to address, otherwise you are likely to find yourself stranded with not only a non-functioning empeg, but a non-functioning car.

tanstaafl.

I agree, a battery dropping to less than 10.5V under load has lost a cell, or has a high-impedance cell.

I would have thought it more practical to sort out the battery/charging circuit than operate on your empeg

I agree, a battery dropping to less than 10.5V under load has lost a cell, or has a high-impedance cell.

Or a slipping alternator belt... or a bad diode in the alternator... or a faulty voltage regulator... or worn/sticking brushes in the alternator... or low fluid [acid] in the battery... or dirty/corroded connections on the battery... or a poorly crimped battery cable... or a bad connection on the ground strap... or excessive sulfation on the battery plates... or... well, you get the idea.

Lots of things it could be, almost all of them easy to find, cheap to fix.

tanstaafl.

It seems that the direct ground lead solved the player dropping out. At least that's what 10 minutes of testing shows so far.
I checked the charging system voltage with the motor at various rpm- all nice and happy- so I doubt I've got any alternator or battery problems.

But now the problem is that my ground-loop whine is louder than ever.
Before, I could reduce the whine by pushing on the face of the player (on the bolt heads - don't hate me). Now there is no 'wiggle solution'. Can't say why pushing used to help.
I tried holding my new negative terminal lead onto the sled and empeg housing- it did alleviate the whine by about 80%. I'll have to find a screw to fit that threaded hole at the back of the sled.

If I can't find a screw or that doesn't solve the whine I'll have to re-install my old head unit for entertainment on the drive. Out would come the empeg for now.
Feel my pain.
Grrr.

I would:

- check shield continuity on each audio channel at the sled
- likewise at the amp
- check the RCA leads
- remove the rolloff caps in your player.

Quote:
The RCA leads from empeg to amp are new, albeit cheap-o, as is the amp.

RED Alert! Danger! Warning!

I would check the grounding of your amp straight away, don't bother with the rest. You should ensure a short DC ground wire, VERY heavy gauge, grounded to bare metal on the car chassis.

I'm willing to put money on you having a puny ground wire that is grounded onto paintwork.

Good man: very similar to my setup. Got surprisingly good results from it as well: it has finally been made to sound superb (in my humble opinion, of course) by using John Graley's Auto EQ in V3A11. Worth trying when you have the install in order, but you will need a mic of course.

Don't forget (if possible) to earth the empeg at the same point as the amp, again with heavy gauge wire.

Ah!
It's wonderful what a good ground does!!

Thanks, Rob!

So you got rid of the whine then?

Glad to be of service, sir!

I'm getting quite good at this, aren't I?

Tony, how about a distillation of this thread for the FAQ? Or anyone fancy turning it into a Wiki article?

There's a Low Battery Icon article in the FAQ already, and there's a section on ground loops in the FAQ already. Everything he did to solve the problem was already covered in both of those places, save for a few touch-ups to the low-battery icon entry that I made as a result of this thread. What specifically would you want me to write?