Quote:
Originally Posted by cooperman
I'm ordering a THA 275 tomorrow, mainly because there don't appear to be any other option. The Alpine kit don't seem to fit my car because there are no connectors in the wiring as described in the instructions. I think the new cars have a different wiring arrangement, from looking at pictures of other cars on here.
Anyway, I'm a bit concerned about whether the Blaupunkt amps are reliable, given one or two reports of failures and poor customer service from Blue Spot.
Does anyone have any info about reliability generally of these amps?
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From what I can gather from various forum members the problem with the Blaupunkt Amp is this. When you connect the Amp to a stock (basic) system it is fine, the problem arises when we owners add the tweeter speaker to the equation. The Front channel of the amp ends up driving 1) the Subs under the seat, 2) the door speakers & 3) the tweeters. These 3 are wired up together in series and the load drops below the 2 ohm limitation of the Amp. This is what is causing the Amp's to blow when any high volume is put through the Amp.
The only way round this is to remove the Sub from the front speaker circuit and connect it to the rear channel of the Amp. The rear speakers are either disconneted or powered from the head unit.
I hope this summary is correct as I am no electrical engineer!
This was a PM i received from a US forum member
Hi Richard
The main problem here is not the filters of the THA475, is the way that you connected the OEM speakers to this aftermarket amp, specifically the front speakers.
Your base system originally have the underseat subs connected in parallel to the front full range 4" drivers. There is a capacitor inline between the 6.5" underseat woofer and the 4" full range driver which accomplishes two jobs: keeps the total impedance in 4 ohms and separates the low frequencies (woofer) from the mid/high frequencies (4" full range).
By adding an extra set of tweeters to the front speakers you effectively changed both the impedance and the frequency filtering.
The filtering can be fixed, but the new impedance can damage your THA475 if it goes below 2 ohms, which it is in fact 1.33 ohms with the new tweeters at least. The amp will eventually overheat and fail if it is drawing too much current due to the low impedance.
If you do not understand all this mumbo-jumbo of technical information at least understand this: you cannot set this THA475 and the front speakers the way you did.
You will need to connect the THA475 4-channels only to the front speakers:
- channels 1-2: connect them to the front 4" full range driver and the new tweeters. Set the THA475 front filter to high pass, at around 150Hz.
- channels 3-4" connect them to the underseat woofers. Set the THA475 rear filter to low pass, at around 150Hz.
The rear OEM speakers will be driven by your OEM HU/iDrive unit.
Regards
Elías