treefrog911

Will give one of those a try I think. I don't think the amp's faulty as this is the 2nd one I've had (although the first one of course wasn't wired properly)...

Sorry to return with bad news. Was hoping to post instead some pics of the install complete with the little 12V fan keeping it cool! As you might remember, I upgraded the power supply cables to my THA275 and that seemed to cure the drop-outs. However, over time have found that it doesn't... it just made the situation better so that these drop-outs weren't happening all the time, and so were less in-your-face. A guy in a car audio shop reckoned I might have a grounding problem, so today I relocated the amp to the boot so that I could run really short power supply and ground cable direct to the battery. Would recommend doing this to anyone as there's a lot more space to work on it there! I've now got an 8mm2 earth wire and really heavy duty alternator cable for the 12v feed. These cables are physically as large as you're going to get fit in the connector block and are wired direct to battery (in fact I had to trim the alternator cable quite a lot to squeeze it in). The power cable has a 40A fuse fitted. Still getting the drop-outs. I can't see how to improve the power situation further. The only possible clue I have is that by setting the balance to full right or full left, the drop-outs become much, much worse. With balance central they still happen, but with it set fully left or right it stutters almost continuously. Also it *seems* to be not as bad without the engine runnning, but definitely still drops out. Any ideas? As a thought, is it perhaps something to do with having the tweeters in-line with the front speakers, messing up the impedance? I don't really want to dismantle the doors to test this, but am frankly happy to throw money at this now to make the problem go away! So is there another amp (that'll work on a speaker-level input signal) I could buy that might be more capable of handling the impedance etc? For example had a quick browse and found a Pioneer PRS-D220 which looked much like the Blaupunkt but a bit higher power?... Thanks in advance, Dave

Thanks Gizze... I wired in a chunky power cable and have been running for many hours now without a glitch, so a very happy man! When I think about it, the cigarette circuit was fused in the boot, so of course it will be a relatively thin cable running a long way (I'd initially assumed it was just a short cable connected to a big busbar at the front of the car). I suspect over that length there was probably a fair old voltage drop under load. With the 14v or so of the engine running this somehow exacerbated things. Now with a larger 6mm2 cable (what I had lying around) it's running very well. Still gets a bit hot, up to 40 degrees or more, but I suspect that's to do with the 2 ohms business perhaps working the amp a bit harder. Also keeping it in the glove box probably doesn't help. However I've salvaged an old 12V CPU fan and might stick that on top of it to help increase airflow. Cheers again! Dave

Thanks for the quick reply. It's a godsend to get input from someone who knows these amps! Unfortunately I sent back the Blaupunkt harness once I realised how straightforward it was to wire it in 'manually'. However will upgrade the 12V and ground wiring tomorrow and let you know how it goes... Thanks again, Dave

The cigarette lighter is fused at 20A I believe. Isn't this enough for the amplifier since it's also fused at 20A too (obviously assuming that I don't actually plug anything into the lighter socket of course!). Sorry if this is an obvious one but I'm no expert here! One more thing, the manual for the 275 recommends a cable size of over 1.5mm2 and I don't recall power cables in the Blaupunkt PnP harness being particularly hefty either, so is this 8 gauge stuff direct to the battery really necessary for this amp? I'm assuming 8 gauge is around 8mm2? Only reason I ask is that it's just that wiring direct to the battery with a big cable was I thought only necessary for the larger amps like the THA 475 that you install in the boot? Cheers, Dave

Thanks for the suggestions. Yes, the amp is set to 8v. I tried running just front-right or front-left as suggested. I did this by disconnecting the *output* pairs of speaker wire where they leave the amp (I left both pairs of *input* speaker wire connected to the amp the whole time). With just one side connected then upon starting the car's engine the cutouts start almost immediately. It doesn't seem to matter which side is connected - the cutouts start straight away after the engine is started. However they don't seem to happen (on my short test) with the engine off (with full ignition on). So appears that connecting just one side seems to make the problem much more apparent, and it doesn't seem to matter which side is connected. I then connected both sides at once again. This time then even with the engine running there were no cutouts after 20-minutes of driving around. However the amp temperature was rising (got to 36.5 C after 20 mins) and so it might start to cutout, as it has before, on a longer test. In case it's relevant the amp is powered from a spur off the front cig lighter using decent 25A-rated cable. Thanks again for the help. Dave

Hi, I really hope that some people can help with this. I've got a 2008 E61 535d with the basic stereo. The car is 2nd hand. I have fitted the Logic 7 tweeters and the Blaupunkt THA 275 amp driving the front speakers. This appears to be a recommended setup from Gizze who appears to know loads about this. I'm finding that when turning up the volume, the sound from the speakers driven by the amp (i.e. not the rear speakers) cuts out every-so-often momentarily. This makes it sound like a CD skipping (though it's not - have tried it with the radio!). Also have just finished a 2-hour long drive with the stereo playing at a low volume. At the end, the amp felt almost too hot to touch your hand on indefinitely. I measured the temperature of the amp in case and it 42 degrees C, with ambient in the car being 25 degrees. The amp was in the glove box with plenty of space around it. I assumed initially that the amp was faulty and got a replacement shipped, but the new amp does the same. I wondered if there was a problem with impedence (I don't know much about this) so I took out a seat to check the impedance of one of the under-seat speakers - it read 4 ohms. Without dismantling the door again I haven't yet checked impedance of the door speaker. The tweeters are the Top Hifi tweeters part #65136978631. I haven't adjusted any of the dials on the back of the amp at all. Any ideas what's wrong? I've been tearing my hair out for 2 weeks now over this! Thanks in advance, Dave