Help with Astrosonix radio

[aevansgatech]

Hey guys,

I have something that's puzzling me. I bought a used Astrosonix AM/FM unit knowing it may or may not work, but cannot figure out where the speaker output is on the unit. I know it originally was linked to a single speaker in the center console so there may only be one output channel.

What I cannot figure out is how do I hook up speaker(s) to it? Does anyone have a picture of speaker wire connected to an Astrosonix? It should be basic, but I do not see any connection points that make sense.

I have 3 wires which I've already sorted out to +12, ground, and accessory and I can get the unit to light up. It also has a thick black connection on the back which I assume is the antenna.

[Nanonevol]

I think you are correct that it would be a mono radio. Could what you call the "accessory" wire be the positive speaker wire? Try it out on a speaker.

[aevansgatech]

Took some pictures, because I'm still not sure what the thing off the back is. Maybe my test speaker doesn't have the right connector? Also, the sides look like they used to have something screwed on.

[Nanonevol]

I also have an Astrosonix radio. The large black connector is for an antenna. The dark blue is 12V power, and should have an inline fuse on it. You can ground it to the chassis. The other 2 lighter colored wires are your speaker wires. Any connection to the speaker will do from simply soldering it direct or soldering on spade connectors.

[DieselSpider]

Kids don't recognize an old fashioned mono radio and how simple it used to be. Analog coaxial antenna lead, single positive power with negative ground from the chassis and a speaker lead with positive and negative polarity. As some speakers have the negative lead going to the speaker frame you should observe polarity on the speaker connection to prevent issues or break the negative terminal to frame connection on the speaker if possible. Some speakers of that era will have the negative terminal riveted to or stamped as part of the speaker frame making it difficult to make the speaker floating ground.

[aevansgatech]

I also have an Astrosonix radio. The large black connector is for an antenna. The dark blue is 12V power, and should have an inline fuse on it. You can ground it to the chassis. The other 2 lighter colored wires are your speaker wires. Any connection to the speaker will do from simply soldering it direct or soldering on spade connectors.

Ok, forgive my ignorance here, but how can the single dark blue wire be both a +12V source and the chassis ground?

[Nanonevol]

No, the blue is the 12V Positive. For the negative connection, connect a wire to anywhere on the chassis ground. I think that will work.

[aevansgatech]

Ah ok, that would make sense. By ground "it" to the chassis you meant the radio, not the blue wire yeah?

I'll test it out with blue to +12V, ground the radio body, and the two gray wires to speaker wire and report back

Thanks nanoneval

[DieselSpider]

I also have an Astrosonix radio. The large black connector is for an antenna. The dark blue is 12V power, and should have an inline fuse on it. You can ground it to the chassis. The other 2 lighter colored wires are your speaker wires. Any connection to the speaker will do from simply soldering it direct or soldering on spade connectors.

Ok, forgive my ignorance here, but how can the single dark blue wire be both a +12V source and the chassis ground?

The radios chassis is the ground and a ground strap mounted between a ground stud/bolt/screw on the radio chassis and the cars frame provides the negative connection. Its all pretty simple tech based on the day when cars were made completely of steel and just about every part aside from the upholstery that wasn't part of the vehicles positive electric wiring was a ground/negative connection. Remember that the entire dash and consoles of most cars made between 1940 and 1980 used to be stamped steel with some padded coverings so therefore part of the ground system. Electrically powered add-ons back then did not have a negative wire except for maybe a 6 inch lead with a star eyelet on it to attach to the most convenient available fastener to provide the negative connection.

[aevansgatech]

So I'm getting proper power and static through the speakers now. I just don't get any stations without an antenna

[Nanonevol]

There you go! Sorry - a diagram would have been clearer. I also have an AM/FM Fiat Astrosonix mono radio but haven't installed mine yet either. I like a decent sound system in my daily commuter but in the Spider I'm not interested. These are nice and they say "Fiat" on them.

[DieselSpider]

Yes you need to plug in the antenna lead to pick up some stations.

If you do not have an external antenna already mounted on the car these internal mount ribbon antennas can work reasonably well if you are not in a fringe area way out in the middle of nowhere and are a bargain at less than $5 with free shipping or for around $7.50 if you get the Zhol branded model:
http://www.amazon.com/Waterwood-Am-Fm-H ... nna+hidden

[Redline]

Sort of related, I have an old Blaupunkt Essen that used to have a single mono speaker on the parcel shelf. I want to put a single speaker instead in the console, but stupidly threw out the old rear speaker without reading the spec. Would it have been more likely 4 Ohm or 8 Ohm?

[aevansgatech]

So I hooked up an external powered flat antenna like DieselSpider's picture, but sadly can only get static and a couple very very very faint stations. I am in an urban area and pick up dozens of stations normally.

Any chance something inside the radio has stopped working? AM reception is 10x louder than FM, but no stations come in clearly

[Nanonevol]

Sort of related, I have an old Blaupunkt Essen that used to have a single mono speaker on the parcel shelf. I want to put a single speaker instead in the console, but stupidly threw out the old rear speaker without reading the spec. Would it have been more likely 4 Ohm or 8 Ohm?

Well, my '77 Spider single center speaker say 4 Ohm 3 Watt on the magnet. Probably not a big deal if you're only going for lo-fi but I think a 4 Ohm would play louder.