Bose system amp replacement - Final result and details

["Rui Fernandes" <rpf@ricochet.net>]

Hello all,

Sad to say but my experiment (reported earlier) with the Radio Shack amp has
gone belly up.

Here is a bit of history on Bose speaker (or speaker drivers if you will):
I am not exactly sure about the dates, but back in the seventies (I
think)Bose built a lot of its reputation with the 901 speakers.  These were
small speakers(by the standards of the time) that had 9 4" drivers that look
just like the ones on the front door of my Audi 100CS.  Bose supplied what
it called an active equalizer with these speakers.  Without it they sounded
terrible, but with it they had amazingly powerful and dynamic sound.  In
essence, Bose builds rugged drivers that don't necessarily sound good, then
makes up for their dynamic deficiencies with a equalizer.
 I am not a great fan of this method, but in some systems like the Bose 901
speakers (with a powerful and expensive amp) the results can sound really
good.  By the way the Bose speakers are hard to drive, but I don't think
that it has anything to do with impedance problems and associated amp
inadequacies, they just have a inadequate response curve, that gets "hidden"
by some fancy equalizing.  I think the same kind of thing happens in the
Audi stereo system except that in the Audi the equalization curve is handled
by the little amps provided with the speakers.
Now what does this mean in terms of upgrading or replacing worn-out or
broken-down stereo components on your Audi?  Well, it means that the stereo
head unit can be replaced by anything that has pre-amp outs (Blaupunkt
radios have all the connections needed and even the right wiring harness
interface plugs).  As far as the speakers and amps, it means that you have
to replace both speakers and amps in pairs.  By this I mean If one front
speaker or amp dies (most likely that the amp dies) and you don't want to
replace with an original equipment you must replace both front or rear
speakers and amps.  There are all kinds of inexpensive equipment that can be
used for this and still maintain a good sounding system.  For the front
Radio Shack sells a small 40 Watt amp that fits in place provided for the
original Bose amp for $15.00, and a decent speaker can also be had for under
$30.00 with some proper bargain hunting.  For the rear you can put in a 100
Watt 2 channel amp and a pair of good quality 6x9 speakers for under
$150.00. Also Autobahn Motors in New Hampshire
603-226-1810(autobahn01@aol.com) sells used OE speakers and amps at very
good prices.
If you decide to replace the original equipment and need detailed wiring
information please email me.

Cheers,
Rui.

PS: I am still trying to find a way to drive those Bose speakers, maybe by
tapping into the existing circuitry.