Speaker Wires

[Pat Marshall]

I'm having speaker wire issues, too. In another thread Holger posted a photo that shows the speaker wire plugging directly into the speaker socket in his radio.

23737

I talked to a business in Columbus which services old radios. They said on the Town and Country radio that the speaker wires go into a clip which then plugs into the radio speaker socket.

I looked at a 55-57 Thunderbird parts website and they offer this for the little birds.

23736

Since the little birds only had one speaker, this won?t work, but that looks along the order of what the guys in Columbus described.

Does this look familiar to anyone?

[Barry Wolk]

I believe you would have to solder a third wire to the unused terminal to power the second speaker. They would use a common speaker ground for you to have front-rear separation.

[Pat Marshall]

I was thinking that the top two horizontal holes are for the front speaker wires and the lower vertical holes are for the rear speaker wires. I was envisioning either a single 4 wire/4 pin assembly or 2 separate 2 wire/2 pin assemblies.

[Barry Wolk]

Sorry, I missed this. Yes, it's stamped into the sheet metal next to the socket what the vertical and horizontal pairs are. Note that the pins appear to be two different sizes. I would hazard a guess that the smaller holes are the grounds and the larger the speaker source. It wouldn't hurt anything if you reversed them, I don't believe.

https://www.markiiforum.com/attachment.php?attachmentid=23737&d=1633952722

[Pat Marshall]

I think I found the answer. This is from Jack Rosen's website. It is a photo of an original front speaker and wiring. Notice that it has a 2 wire/2 pin front speaker plug assembly. So, it appears to me that the wire from the socket to the rear speaker would have a similar 2 wire/2 pin assembly.

23738
23739

[Barry Wolk]

Hmmmm.... Explain this.

23740

[Barry Wolk]

And then this bit of contrary info. only 2 wires where the first showed 3.

I think you're looking for a common 2-pin phenolic plug with 2 different size orientation holes.

23741

[Milsteads Garage]

Hmmmm.... Explain this.

23740

I can explain exactly what it is. Your two parallel wires aren’t actually. It’s one wire that’s sheathed to prevent RFID static noise from the ignition wires to stop feedback.

[Pat Marshall]

I know what happens when I assume, but I assume that the larger hole is for the (larger?) sheathed wire and the smaller is for the ground.

I checked my (3) II's and none have plug-in pin assemblies and all have what looks to be newer common speaker wires.

[Pat Marshall]

Breaking News -

My local old time radio repair guy located the Town & Country radio two-prong speaker plugs in Philadelphia and is having them sent immediately.

Morgan, could you expand on the wire that is referred to as a "two conductor wire" in the drawing and that you said is a sheathed wire.

Earlier today, I talked to Jack Rosen about the "two conductor wire" described in the drawing. He said "I've never heard of that!" I told him I'd let him know what I find out.

[Milsteads Garage]

The “two conductor” wire on the MarkII radios was a normal electrical wire with a braided sheath built into it to control RFI “radio buzz” caused by original spark plug wires. To elaborate, the original construction of a MarkII spark plug wire is it had a metal wire core covered with rubber insulation. Often times, this rubber sheath was not enough. Whenever 20,000 volts pulsed through the spark plug wire, it created its own field and would cause the radio to buzz which is known as radio frequency interference. How Continental dealt with this is adding a sheathed 2 conductor power wire which the inner core sent clean power to the speaker and the outer conductor simply carried stray RFI so it would not create static or white noise.
All speaker wires were back then was regular electrical wire but with a secondary sheath cast between the inner wire and the outer insulation on the positive side only. It wasn’t needed on the negative side because stray voltage would return to an earth ground before it would affect how the speaker worked.

That was the 50’s, here is what’s going on in 2021. Automotive speaker wire still is dual conductor and a specialty type wire instead of an electrical wire modified as an afterthought. Solid core wires also made an official mainstream exit during the 1990s and was replaced with the type of resistor/silicone wire that eliminates ignition RFI almost all by itself. That’s why modern spark plug wires don’t actually have wire in them, it’s carbon fibers.

More on spark plug wires: Barry posted a TSB some time ago concerning switching the positions of wires 8 and 6 in the spark plug wire brackets because they caused a misfire. This is true because 8 and 6 fired sequentially and the spark from wire 8 would often jump into wire 6 and vice versa. This needed to be done with solid core plug wires but is much less of a problem with modern resistance wires. I like running spark plug wires made for boat engines because they are built with better quality to prevent spark scatter and meet requirements to be used in a closed engine compartment with poor ventilation.

[Pat Marshall]

A very helpful post, Morgan!

So, any modern speaker wire will work on a Mark II?

That's great and makes things a lot simpler! Thank you!

[Barry Wolk]

I was in the CB/car stereo business in the '70s. Trained dozens on installation and never saw or heard of speaker wire like that. Anyone have a sample? My car has no place for a rear speaker.

[Pat Marshall]

Went rummaging in my storage building today and found a dead speaker with the original wires still attached. The fitting with pins to which the wires are attached broken, but the difference in the two wires (the two conductor wire and the ground wire) and their pins

23751can be seen.