[AMPS] stupid question

[Bob & Linda McGraw K4TAX]

Folks, I have a slightly different spin on this RCA, phono, phone, and
Motorola plug story.

The RCA plug is generically called a phono plug today.  Yep RCA did put
it on the 45 RPM changers and their associated Hi-Fi equipment in the
late 40's and early 50's.  Still quite popular on todays equipment for
both audio and some low power RF applications.

The Motorola plug is quite different.  It is the type typically used on
auto radio antenna connections. The chassis connector has a female
center pin and a female outer sleeve.  The cable connector is about 1.25
to 1.50" in length overall.  There is a female cable connector found on
may import auto radios today.  To the best of my knowledge the lead from
the antenna is always male & male in the auto's today.

The RCA chassis connector has a female center pin and a male outer
sleeve.  The cable connector has a male center pin and a female outer
connection.  Overall, they are about .75 to 1.125" in length.  There are
2 types of RCA connectors. One has a long center pin while the other has
a short center pin just barely extending past the outer sleeve.  The
latter one is typically found on GE type equipment as it's not very
prone to short to something when a cable hangs loose.

While I've seen the male phono plug inserted into the Motorola chassis
connector it typically makes for a sloppy fit.

As to phone plugs, these are typically tip-sleeve type connectors and
the old standard is 1/4" in diameter.  The stereo or 2 circuit version
is known as a telephone plug or a tip-ring-sleeve.  The military version
has a slightly smaller diameter barrel.  I am aware that Collins has
been known to use these on the KWM-2 line of equipment for the
microphone connector.  The headphone connector was the standard 1/4"
phone plug.

Darn confusing, isn't it.  Hope this helps.

73
Bob K4TAX

Tom Rauch wrote:
> 
> > Is the 'RCA' connector the same thing we call a 'phono plug'? The type
> 
> RCA connector is something that has crept into common usage. I
> don't know where it came from, it has gradually appeared. Many
> names are like that.
> 
> There are is a special type of plug that looks like a phono plug but
> isn't a phono plug. The standard phono plug that every domestic
> manufacturer (GE, Philco, Magnavox, Motorola, RCA) used for
> phono applications, and an extended-tip-male recessed-center-
> female used by Motorola for RF applications.
> 
> The Motorola plug would sometimes bottom out in a standard
> phono connector and not seat. I remember cutting the tips off about
> 1/4 inch when swapping GE equipment into something built for
> Motorola RF decks, and having to solder standard phono plugs into
> Motorola gear like low-pass filters for 150 MHz.
> 
> The phono plug comes up short of a good fit in Motorola RF jacks,
> like those used on Motrac and Motans other two way radio gear.
> They will work, but barely.
> 
> Of course the early Motorola mono and stereo record players used
> standard phono connectors.
> 
> I think part of the name change was become non-technical people
> buying parts confused phono and phone, which are two different
> connectors. (The phone connector was originally called a telephone
> connector.) Headphone jacks on our radios use (tele)phone
> connectors.
> 
> > of connector used on the Heathkit HW101 antenna connector, and I
> > believe, either the KWM2 antenna connector or the 30L1 input connector
> > - not sure which.
> 
> Heathkit uses a phono plug, I'm not sure if the Collins is a standard
> phono or Motorola-style plug.
> 
> I recently got into this when I told a new person doing a layout to
> change a plug to a phono plug, and it arrived with a phone plug.
> The old engineer knew the difference, and even knew what a
> Motorola plug was. The youngster had no clue. He thought the
> phono plug was called a RCA and the phone plug was a phono.
> 
> 73, Tom W8JI
> W8JI@contesting.com
> 
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