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From: mat@mtx5a.UUCP (m.terribile)
Newsgroups: net.audio
Subject: Re: Wiring problem for car radio and tape deck
Message-ID: <1193@mtx5a.UUCP>
Date: Tue, 18-Feb-86 01:28:58 EST
Article-I.D.: mtx5a.1193
Posted: Tue Feb 18 01:28:58 1986
Date-Received: Sat, 22-Feb-86 01:55:55 EST
References: <65@oucs.UUCP>
Distribution: na
Organization: AT&T Information Systems, Middletown, NJ 07748-4801.
Lines: 49

> . . . I have a standard radio in my car with 8 speaker wires coming out -
>  . . . I have a tape deck with four speaker wires - two to the right
> and two to the left speakers. My switch has four wires for the tape deck 
> connection (just right), and four wires for the radio connection (not right.) 

Tim:
	If you want to use this setup, you are going to have to get an
8-pole switch.  Why?

	Basically, your radio makes one set of assumptions about the speakers
and the tape deck and switch make a second, conflicting assumption.

	The radio expects to have direct access to both terminals of each
speaker.  This means that you cannot assume that one terminal of each is
at ground.  4 speakers times 2 wires/speaker = 8 wires .

	The tape deck and switch assume that one terminal of each speaker is
grounded and that only the ``hot'' leads (wires) need to be switched.

	If you want to go through with this, you will have to find a 8 pole
double throw switch.  Your best bet is to look for a rotary switch, possibly
a 12PDT (12 pole, double throw)  ``Pole''s are each a complete set of contacts,
a switch within the switch.  ``Throw'' refers to the number of different ways
that the switch can be ``on'' -- two, in this case, for the two different
inputs that you wish to select.

	What you will do is first figure out how you will mount the darn thing
mechanically in the car.  Then connect up the radio, using the common terminals
of the switch to go to the speakers, and one switched terminal of each pole
to go back to the radio.  Be consistant, of course, and then get it all working
again.  Take the car over some cobblestones to check out the connections:
connections in a car are bastards of the worst order.

	Then, for each speaker, connect the appropriate hot lead from the deck
to one pole on the open switched terminal, and connect the other pole's
terminal securely to the chassis ground that the tape deck uses.

	Note that I did not say I recommend this setup.  Unless there is
something special about the deck (8-track, and you have a large collection
of 8-track tapes) or about the manufacturer's radio, you will get much
better results with a good 3rd-party deck and speakers.  Of course, if
you are on a budget ...
-- 

	from Mole End			Mark Terribile
		(scrape .. dig )	mtx5b!mat
					(Please mail to mtx5b!mat, NOT mtx5a!
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