03 530i getting no audio, only electronic noise with aftermarket amp

[Scotes]

I took the multiple Alpine amps out of my car and am now trying to install a Blaupunkt THA-555PnP amp to consolidate the mains and sub all under one amp. I am having a problem where once everything is hooked up the amp powers up but I just get electronic noise through the speakers.

This is with the car off - not alternator noise. It sounds like electronic communication as if it was from a fax or modem - perhaps ibus signals. If I play with the volume I can hear clicking as I turn the volume up or down. I get no audio material what so ever though through the stereo through any channel.

The car is a 2003 530i which has navigation and no DSP. I am plugging directly into the 26-pin connector with male 26-pin connector I have. The pins are on pre-made OEM BMW leads with the correct pins. This goes to to a 12-pin molex connector (of which 8 pins are used) which connects to a set of twisted pair RCA cables. I have checked continuity on all of the leads and they are fine. Pin layout I am using are #'s 1, 2, 3, 4 for RR-, RR+, LR+, LR- and 14, 15, 16, 17 for RF-, RF+, RF+, RF-. I know these are the correct pin outs. I had also tested this cable on the old Alpine 545 amp I had and it was fine so I am at a loss here.

Anyone have any suggestions as to where to start to fix this problem?

[Scotes]

Anybody got any thoughts on this?

I went out and borrowed an Alpine 4-channel amp and leaving all of the wiring as is plugged it in and that worked fine - so I know that there is no problem with my wiring. Plugged the Blaupunkt back in and no joy. I had Crutchfield swap out the Blaupunkt and got that today. Plugged the new amp in and just like the first one was just getting the digital noise through the system - still no joy.

Could this have something to do with the Blaupunkt maybe not being able to accept the (what I understand are) balanced outputs of the BMW head unit? The three Alpine amps I have tried have all worked fine. I had also tried an a/d/s p840.2 and had the same problem as I am having with the Blaupunkts.

The Blaupunkt has what they call their PnP input. I found out yesterday that if I use the RCA input I have to have a separate sub input to drive the sub channel but if the PnP input is used then it will derive the sub channel from the front/rear there. However, the PnP input is only usable with a special cable that they of course don't make for US spec BMWs.

I hoping someone has some thoughts on this. The next step is to try the new Infinity Kappa Five 5 channel amp that is spec'd to accept balanced inputs.

[Scotes]

So after a bunch of searching I think it is the balanced vrs unbalanced input issue.

Alpine amps - f345, f545, f300 - all able to accept balanced signal on RCA input connection with mac 4v signal. All worked. Manuals do not specify this anywhere.
a/d/s p840.2 / Blaupunkt tha-555pnp - not able to accept balanced signal over rca. a/d/s might be able to over din connection and Blaupunkt maybe over their PnP connection but this is not noted in literature for either.
Infinity Kappa Five - specifically notes it takes a differential balanced input over its RCA jacks so this should work without a problem I believe.

Anybody?

[jvr826]

VINCE!!! Back at it I see. I happened in here after a PM on another issue, figured I'd confirm what you've determined.

You need a Line Output Converter. I had the same problem when I did my 2002 with Navi, even though the stock amp had the same part number as the 1999 without Navi. Drove me nuts!

I bought a Peripheral VEN4 at first, but it was introducing noise, so I went with a used Audio Control EQS which has an active LOC built in... end of noise problem.

http://www.audiocontrol.com/t34/Mobile-Audio.html

[Scotes]

Hey Jeff! Yup - I wasn't happy with all the amps taking up so much space in my trunk and wanted to simplify to a smaller setup while still powering the sub. I reckoned it was the balanced output to a balanced input problem but didn't really think about it previously as the Alpine v545 amp was able to take the balanced signal without a problem. I've got an Infinity Kappa Five amp arriving on Monday that essentially has an LOC built in as it has differential balanced inputs - so that should work without an additional loc.

Also - note that the Blaupunkt and the a/d/s p840.2 weren't introducing noise as all I got out of them was noise. Like digital blips. Odd thing about the amp on the nav/non-nav - when I retro'd the nav in my 530i I didn't change the stock amp and that works with either setup. Good thing I didn't sell it - until I get the Infinity that's what I'm using!

[jvr826]

The problem I had without an LOC and Nav was the P840 amp would cut out immediately after turning the system on, IIRC.

Sounds like you've got it sorted out. I've since retired the P840 as I fried it on a long road trip. I have had it repaired, but it took forever, so I went with a DLS Ultimate A5 instead. That has been under my trunk floor for a couple of years without any problems. It has a neat fan output connection that turns on a 12v fan, or fans in my case, if the amp reaches a certain temp. Piece of mind on those long trips to far away tracks.

[Scotes]

So got the Infinity Kappa Five on Friday and wired it in over the weekend - problem solved - the balanced inputs on the Infinity take the balanced outputs of the OEM deck with no LOC needed. I've got a tiny bit of ground loop whine probably caused by the mess of wires from the scratch hook up to make certain it works but that should clear up when I properly mount and rewire it.