Minimum Ohm Requirement?

[Zonaman]

Got an original GM radio in my dash and I'd like to wire it up again. Question: Isn't there a minimum ohm requirement for the speaker on that? Also can i get some type of splitter for the radio antenna so both units can use the existing antenna?

Thanks

[Dead Parrot]

Not sure about a minimum. But best operation is when the speaker and radio match. IIRC late 60s and 70s radios were 8 ohm. Later ones went to 4 ohm.

[Zonaman]

I seem to remember 8 ohms too.

[damnyankee36]

Speakers of that era are 10 ohm.

Splitters are available too.

https://www.google.com/url?sa=i&url=...r4kDegUIARCGAw

[Zonaman]

That's good news. Are there any diagrams or photos around that illustrate how the factory brackets fit together for the radio and speaker?

[damnyankee36]

Here are a couple from a 68 I am building.

[damnyankee36]

I just took a few more for ya...

[Zonaman]

Thanks! Does that assembly act as a ground in any way for the radio or speaker?

[damnyankee36]

The radio is grounded through the brackets and I think the speaker is also grounded to the body electrically, but not directly. If it is grounded it's through the radio/speaker harness. Here's a photo of the harness.

The speaker wires are permanently attached to the speaker and its 3-terminal connector plugs into the back of the radio. The red power wire plugs into this same connector and the other end connects to the fuse box to the left of the "RADIO" fuse.

[Zonaman]

Yeah, thought so. My brackets are long gone. So if get a screw strap on there and use it for a bracket (along with the speaker ground) that should ground the beast?

[Zonaman]

Is there a decent, reasonably priced 10 ohm speaker on the market? Thanks again for all pictures!

[damnyankee36]

Yes, grounding the radio case will get everything working for you. I don't know of a10 ohm speaker off hand. I'm sure you get can one reconed.

I'm pretty sure the setup I have will not be used in this build. The owner wants a modern stereo, like RetroSound along with kick panel speakers to go in the truck.

PM me if you're interested.

[Zonaman]

Picked up 10ohm Delco 6x4 oval in good condition at a local garage sale. Looks like I'm in business. Thanks.

[Zonaman]

Anyone recognize this type of speaker plug. Still available?

[pjmoreland]

That looks like the kind of connector that is on the speakers in my '89 Chevy truck. I am in the middle of replacing the rear speakers, and I bought a set of replacements at the wrecking yard. I have the original connectors that I cut off the donor truck. I'd be happy to send you one if you pay for the shipping.

[Zonaman]

Thanks but I ended up cannibalizing the connecters from another speaker and it fit okay. So just waiting for my antenna splitter plus some odds and ends and I'll see if my Frankenstein lives.

[Zonaman]

One other detail: What's the correct fuze size on the stock radio?

[pjmoreland]

The radio fuse in the fuse panel is marked "3A"

[Zonaman]

Originally Posted by pjmoreland

The radio fuse in the fuse panel is marked "3A"

3A check, thanks.

[Zonaman]

Got everything wired up but could only get a very weak broadcast. Ground is good- screw strap from back of radio right to the body , antenna good (other radio is fine). speakers are wired up right. Only thing I noticed was the static was a bit louder when I put a little pressure on the volume button. Any thoughts?

Thanks.

[Zonaman]

Something else: Since I didn't have the bracket that the speaker sits in and I did think it was a good idea to have the speaker in the factory location right in the front dash where the Arizona sun could do its work on it, I ran the speaker wires down the firewall and under the seats to the center console. It sits in a speaker box there. I bring this up because factory bracket has the speaker magnet itself in direct contact with the body ground in a big way. Did I by any chance "screw the pooch" by setting it up this way?

[pjmoreland]

I have bench-tested multiple OE radios with a speaker sitting loose on the bench, and it has worked just fine that way. I don't think the housing of the speaker needs to be grounded. I saw some stock speakers in a mid-90s Chevy truck recently that were mounted in plastic housings that isolated them from the metal body.

[Zonaman]

Radio is damaged likely?

[pjmoreland]

I had a damaged OE AM radio that produced nothing but quiet static that didn't change when the tuning knob was turned. My guess is that it had been powered up without a good 8-10 Ohm speaker attached at some point. I ended up replacing it with another AM radio that did work.

https://67-72chevytrucks.com/vboard/...d.php?t=814243

[Zonaman]

Originally Posted by pjmoreland

I had a damaged OE AM radio that produced nothing but quiet static that didn't change when the tuning knob was turned. My guess is that it had been powered up without a good 8-10 Ohm speaker attached at some point. I ended up replacing it with another AM radio that did work.

https://67-72chevytrucks.com/vboard/...d.php?t=814243

Maybe. I recall reading something about that radio needing a 7 ohm speaker which is what I had on it one time. I probably messed it up with that.