Replacing Bose head unit

[Roo15]

I have removed the din2 Bose head unit in our NB 99 and fitted an aftermarket Pioneer din1 unit, but can't get any sound out of it. Looking at other messages on this site and other places on the internet it seems that Bose run odd speaker specifications, is this correct? Is there an alternative to removing the amp and replacing the speakers in the doors?

[Grant]

The Bose speakers are very low impedance....about 0.5 ohms! The amplifier is
designed for this load and has equalisation built in to 'enhance' the
frequency response of the special speakers. The amplifier is a balanced
input (I believe) which can be fed from a standard head unit as long as you
can build, beg, buy a suitable transformer coupled interface. The tweeters
are standard cone type. I looked into it when I bought my 1998 with the Bose
units. In the end I decided it was much simpler to forget about the speakers
and amp as from my research (and listening to it) the speakers were way past
their best and sounded awful!
I picked up a pair of 200mm subs at Super Cheap and installed them. Plenty
of room in the doors for the depth and the diameter was a good fit.
Connected the tweeters and the results were quite good. Had to reduce the
highs and mid range a bit to compensate for the too sensitive tweeters. Much
more satisfactory than persevering with the Bose unit. I've kept all the
bits for when I buy that NC eventually.
Some manufacturers make some good 200mm three way speakers (Pioneer I think
do) which would be a good way to go. Couldn't find any though when I was
looking. Haven't seen the 200mm subs anywhere either since I bought mine.

Grant.

[MX5PWR]

The Bose amp needs to be powered up to work. There is a small wire (white/green from memory) that needs 12v. The wire is part of the wiring loom that went into the factory head unit so have a look for the wire that is not being used. When I did mine, I used the external power amp wire from the head unit or you could attach to the auxiliary wire . I had my head unit going through the built in Bose Amp and existing speakers. The amp and speakers are a different rating however I never had any problems.