[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Grounding radio/popping

Preston - I don't know what to make out of this speaker mess.  
To clarify: You don't have the Bose system, right?  And I do.....

I confess that your wiring diagram was not clear enough for me to 
follow.  I could do better with a columnar list:

Radio LF+> Adapter LF+
Radio LF - > Adapter gound wire 

Can you re-cast your diagram in this (net-proof) layout?

Your front speakers must not be Bose, or they wouldn't need an 
amplified feed.  The factory wiring diagram shows that there is an 
amp for the rear speakers (in the stock 200),  so it seems to me 
that those feeds must be line level, compatible with the adapter's 
output.  (Is this the Crutchfield 166PWRMTCH adapter?)

Why not run wires direct from the replacement radio to the front 
speakers?  That bypasses the adapter, which you can't use if you 
have to send amplified signals to the fronts anyway.

The common wisdom is NOT to ground the speaker negative leads.  If 
you have only two ground wires per side, maybe bypassing the adapter
and wiring the fronts direct will help by eliminating one pair of speakers 
which use the shared ground wire.  

I suspect the pop is due to something the Crutchfield unit is not 
dealing with.  I'm also working with a gent on the Z-car list who is an 
electronics designer, and he thinks it's a voltage spike which can be 
damped with a big capacitor at each speaker.  I can handle that 
pretty easily - adding a cap is not much work - but it bugs me why it 
should be needed.  It will be this weekend before I can do much 
with it, but I will gladly post the results.  I also will do one more 
go-round with Crutchfield's tech department to see if we can get it 
solved using the new, zoomy adapter they sent 
me.  However - the solution I come up with will be Bose-specific.

One more factor - I have 58 days to complete a PhD or lose a class I 
took almost 10 years ago - if I have to park all of this and finish 
the degree first, I'll have to do so........

If you want to email me direct, I'll try to help as I can....but I 
think Steve and others are very sharp in this area.  We'll get it in 
time.  I'm not rushing since I can shove the Bose radio back in place 
in about 30 seconds, and haven't burned any bridges with my hookup.

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