I am using my stock Concert headunit, and coming out of it using the Blaupunkt pinout-RCA cables, running to an amplifier.

It worked okay with the ADS P440 that I had.
But I had to dial the gains WAY down to keep alternator whine out of the speakers.

I suspect that the Concert radio has a pretty low voltage output through those RCA cables.

Someone mentioned that I should try out a line driver, to boost the voltage of those line level outputs.

Looking at Soundhabit's website, I notice that AudioControl has one, and so does Phoenix Gold.
(Probably others too, but those two are what I found so far.)

I sent back my P440, and ordered a Phoenix Gold 75w X 4 amplifier. Should I also consider buying a line driver to boost the voltage to the amp ?

Where would this thing get installed ? In the trunk near the amp ? Or up front, before the RCA runs ?

Any thoughts ?

Thanks,
Peter
98.5 1.8tqms
JL Stealthbox
PG 4600 on order
Focal 130k on order
right now the car is silent, since the amp is disconnected.

I used it in my old Acura. Good results, and solved the alternator whine (or should I say, drastically reduced it). A four channel version was about $250, and a two channel was about $200 I guess. Don't have the ph. # of the company though.

This unit would get mounted as close as possible to the head unit. You want to minimize the length of RCA running at the lower voltage, otherwise if you have an RCA cable with induced noise going into a line driver, your alternator whine will get bumped up too!

As always, try your equipment first, and see what results you have before buying more boxes to include in your signal path. With the price of the line driver, you're already within shouting range of a new head unit, which should preclude the need for the line-driver, and should sound considerably better than the factory. As an aside here, I just had my system installed. The music sounds compressed in the midrange. Not sure if it's the factory head unit, I still need to set the crossovers and bass eq properly.

but there's no mention of pre-out voltage. However, a check of the archives reveals the following:

"Posted by GaryJ on 1999-10-07 17:31:38:
. . .

They're not RCA, so RCA plugs would need to be added to plug into an amp. The line-outs are 1.5-2.0 volt."

Since I won't get my TT for another week or two, I am unable to measure the voltage myself. HOWEVER, in past car audio applications over 12 years, I have had several systems with only 1.5-2 volt headunits with no noise whatsoever. I also ran the amps with the gain at an acceptable level.

Accordingly, I think your noise problem has more to do with a bad ground or interference into the signal path (proximity of signal & power wires).

-John P.<ul><li><a href="http://www.blaupunkt.de/asp/index.asp?Sprache=english&topic=AUDI-ConcertPlus">http://www.blaupunkt.de/asp/index.asp?Sprache=english&topic=AUDI-ConcertPlus</a></li></ul>

check all your connections and grounds...make sure they are snug and not conducting with anything else (other wires and such)
second try upgrading your grounds from 10 ga to 8 ga or 8ga to 4 ga, that should cut some noise too.
Line Drivers IMHO are just a bandaid for a problem that should be fixed by other means. However the output of the stock headunit MAY be the cause of this.
Investigate further before spending the money.


Cheers

Darren

Hey Guys --
Thanks very much for the useful information.

With the ADS amp in my car, and the gains cranked down to alleviate the alternator noise, the system actually sounded quite good.

But knowing that the Concert headunit does not have a very high voltage output, I was wondering what kinds of improvements I would see with a Line Driver -- reduced noise floor perhaps ?
(Yeah, as if the tires didn't make any noise...)
More headroom before clipping ?

If I get the Phoenix Gold amp to sound as good as the ADS did, I'll be quite pleased.
(I do hope that I'll have more headroom, just based on the fact that it's almost twice the wattage.)

I should have the amp by the middle of the week, and then I'll decide if I want to spend the money on a Line Driver.

Thanks again,
Peter