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Posted by: jim_hoyland Aug 29 2013, 06:08 PM

Got this vintage Saphire radion and want to wire it to each side speaker; it was originally wired to just one speaker.

I'm thinking that spliting each of the two wires will do the trick ? If not I'd like to know.

And, can this radio be wired to an amp ?


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Posted by: JawjaPorsche Aug 29 2013, 06:30 PM

Splitting the wires to have two speakers will work. I don't know about an amp since you have just am. I put an am radio in my car. It works but I prefer to listen to motor and Bursch muffer. I like the retro look! See my link below for radio picture.

Posted by: Harpo Aug 29 2013, 06:52 PM

Send it to Bill Henn in Florida. He added an ipod adapter and amp outputs in my sapphire radio. If your interested I can give you his address.

DAvid

Posted by: jim_hoyland Aug 29 2013, 07:05 PM

Would you PM me the info

Posted by: jim_hoyland Aug 29 2013, 07:11 PM

I'm going retro fo the same reason. I had acPioneer AM,FM,XM, CDR, wired to a JVC amp and some Hertz speakers. The most I listen to is trafific reports.

Posted by: CptTripps Aug 29 2013, 09:17 PM

Be careful. Is the impedance rating listed at all?

Car audio speakers normally have an impedance rating of 4 ohms.

If that radio was meant to power one 4 ohm speaker, and you split it to two, you'll be operating at 2 ohms and likely cause damage.

Posted by: jim_hoyland Aug 29 2013, 09:59 PM

How could I measure that ? Would I add a resister to fix that ?

Posted by: bandjoey Aug 29 2013, 11:01 PM

If this helps. Owners manual and wiring diagram for a Saphire
http://www.914world.com/bbs2/index.php?showtopic=218168

Posted by: CptTripps Aug 30 2013, 05:35 AM

Cool...this is easy then.

Looks like they had one connected, but that is actually a 3-wire system using a common ground (center pin).

Take a look at the 3rd wire that's not attached to the connector in your picture. My guess is that it's the other speaker's "+".

Wire em up...you'll be fine.


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Posted by: jim_hoyland Aug 30 2013, 06:07 AM

The connector on mine is two wire.

Posted by: CptTripps Aug 30 2013, 06:33 AM

Hmm...

Ok. You'll need to check the SPEAKER with a Multi-Meter, set to Ohms.

If the speaker is 4.5-8.5, you're within range of an 8-ohm speaker. From there, we can determine what resistor and how you'll need to wire them up.

Give me 5min and I'll put a chart together.

Posted by: CptTripps Aug 30 2013, 06:38 AM

Here's a quick chart I found that shows how to wire them up to match.

After you figure out what the existing speaker is, you'll just need to make sure you match it with the two speakers. If you are currently driving 8-ohms, and you drop to 4-ohms, you'll likely cause your radio to lose it's magic smoke!

You'll obviously be "Mono" but if you're rocking an AM radio, I don't think this will be an issue for ya.

Hope that helps.


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Posted by: jim_hoyland Aug 30 2013, 06:54 AM

Each speaker currently termnates under the radio with 2 wires each, one black and one red.

Should I measure the resitance at the end of a pair ? Or, does the measurement have to be made at the speaker ?

Soon as it get light, I'll measure and report back.


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Posted by: CptTripps Aug 30 2013, 06:58 AM

Always measure the speaker, without anything connected to it.

You're measuring the resistance of the voice coil. Try it at the terminals on the speaker, and if you can reach it without damaging the speaker, touch the leads from the coil too. (usually on the back of the terminal.) This will also tell you what kind of resistance the terminal is adding, and give you a more accurate reading on the speaker.

Although in this circumstance, you're trying to match the current resistance, so measuring the terminal is the best way to replicate what you have.

Posted by: jim_hoyland Aug 30 2013, 07:31 AM

Preliminary results, I'll have to go back and pull the speaker covers later to make a direct measurment, but here is what I have at the wires terminating under the dash ( radio):

1. Car speakers 6 ohms each
2. The original speaker shown in the picture above 6 ohms at the plug and tabs

And, how does one distinguish the + and negative wires ? It was many years ago that I installed the newer speakers, and as I remember I maintained the black/red correctly.....

Posted by: CptTripps Aug 30 2013, 07:45 AM

If they're reading 6 on your multi-meter, than thats an '8 ohm' speaker. (There's a WIDE tolerance!)



That's a little tougher. NORMALLY the "-" is on the left, but we're talking about a 40-yr old german car...so it's anyone's guess. There's no real way to measure the coil to tell you.

IF you make them the same on both sides, you won't experience any phase shifting. You can also switch it back/forth and see which way sounds better to you. The speaker won't care. (Kinda like the old "wire doesn't know what color it is" adage.)

Posted by: jim_hoyland Aug 30 2013, 08:41 AM

Which wiring scheme from post #12 would be most suitable ? BTW, I replaced the 40 year old speakers with a modern set of Hertz that fit into the original grills

Posted by: nathansnathan Aug 30 2013, 10:51 AM

I'd wire them the bottom way, in series, to make a 12 ohm load. If they are 6 ohms each, wiring them in parellel would make a 3 ohm load, which would probably fry the amp.

Lower ohm speakers will make the amp work harder, even though that seems backwards. It helps to think about how sometimes they will say an amp is "2 ohm stable" - that one probably isn't.

Posted by: CptTripps Aug 30 2013, 12:41 PM

It's always better to err on the side of a higher number.

Lower ohms + Old Amp = Blue Smoke

Posted by: jim_hoyland Sep 3 2013, 08:37 AM

I ended up wiring the two speakers in series and they work great ! Thaks for the input Before connecting anything, I tested each speaker wire for polarity with a Dcell battery.

No static, the stations I do listen to are very clear.


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Posted by: CptTripps Sep 3 2013, 08:46 AM

Great work! I forgot all about the battery trick.