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<All> Mo'Bose Prollums (kinda long)



This is one of those rare messages I can post to both the Quattro 
group and the Z-car group, since in involves the Bose system which 
pesters members of both groups!

WHEN REPLYING TO THIS MESSAGE, PLEASE DO NOT CROSS-POST TO BOTH LISTS 
UNLESS YOU DO IT ON PURPOSE!  CHECK THE RETURN ADDRESS WHEN YOU HIT 
"REPLY" BEFORE YOU SEND YOUR MESSAGE.

I have spent about six hours fiddling with my Bose-to-Sony radio 
conversion over the past two days.  I'm using Crutchfield's new 
Bose adapter, and to give credit where it's due, Crutchfield has been 
unfailingly helpful and incredibly patient and willing to try various 
ideas - I have spent over three hours on the horn at their expense 
over their 800 tech line!  They are really nice to work with.

The persistent problems I have not been able to solve are a residual 
hiss which is about 1/3 the volume of the radio at conversational 
volumes, and a loud POP when turning off the radio.  Over time, this 
POP may damage the speakers, so it's bad juju.

I have shipped my Bose radio to Crutchfield, where one of their 
research guys is going to put it on the bench and test it with their 
new adapter.  He plans to work the adapter over until it performs just 
right.  I sure can't bitch about getting this kind of support when it 
would cost me $40 to $60 per hour - and they're doing it at no charge 
to me other than the shipping to get it there!

One reason I'm going thru this is that if they get this adapter just 
right, then the members of both email groups will know they can buy 
an adapter that really works right - and Crutchfield will have a unit 
which they know performs well.  I think this is a real win-win deal!

I do have some questions which I hope some of you folks can help with.

1)  For the Audi group: does anyone know whether the amps in the door 
enclosures also drive the dashboard speakers?  I ask because I've 
noticed that the speakers in the dash and doors seem to be linked 
on the fader, as the "front" set, and the rear deck speakers seem 
to be the only speakers functioning as the "rear" set (which 
makes sense.)  The answer is important for two reasons:

    First, if the speakers are in series, it means that I only have 
    one set of amps to mess with.  Good news.

    Second, one option in converting a Bose system would be to 
    bypass the amps at the existing speakers and run new wires 
    directly to the speakers.  BUT - doing this with door and dash 
    speakers in series would result in more load on the radio, and 
    this might be a problem.

2)  For Audi and Z-Car types, can ANYone offer an opinion as to why 
my dash speakers stopped working when I disconnected, then re-
connected the passenger side speaker enclosure?  All I did was take 
some test measurements on the speaker with a digital Volt/Ohmmeter, 
but when I re-connected it, I have no dash speakers.

3)  Finally, mainly for Audi types, has anyone actually looked inside 
the dash and seen where the speakers ARE?  I removed the perforated 
screen from the RF dash speaker and looked in - there's NO speaker 
visible, just a hole into the dash!  I guess the speaker is located 
off to one side and is ported thru the hole, which would be just like 
Bose.....but I'm curious.


A note about options:
FINALLY - in case I am NOT able to come up with a suitable adapter, 
Josh Karnes on the Z-car list suggested one option would be to simply 
disconnect the amps at each Bose speaker and wire direct to the 
speakers from the new radio.  I pulled one of the rear deck speakers 
and I can report that this would be EASY!  The speaker enclosure is 
two parts - there's an outer housing which includes a PC board with 
the amp; held in place by that enclosure is a standard 6x9 speaker.  
The amp outputs are simply standard press-on spade connectors at the 
speaker, so they would be easy to pull off - and new wires could 
easily be connected with spade connectors.  I didn't take apart the 
door speaker enclosure since it has 16 screws holding it together, 
but I'll bet money that it would also be very easy to disconnect that 
amp.

So it might turn out that the easy way to make a conversion is to 
unplug the power leads to the Bose amps at each speaker and wire 
direct to the speakers.  I will use this option is necessary, since I 
hate to turn down free amps at each speaker!

I have also taken some measurements of voltage, impedence, etc. of 
the Bose system and will talk to Josh about whether we can make our 
own adapters to get around this whole mess.

TTFN  (ta ta fer now, folks..........)
Al Powell                           Voice:  409/845-2807
Ag Communications                   Fax:    409/862-1202
107 Reed McDonald Bldg.             Email:  a-powell1@tamu.edu 
College Station, TX  77843-2112
W3 page - http://agcomwww.tamu.edu/agcom/satellit/rpe/alpage.htm