TV with 14v brick, okay at 12.x volts?

wa8yxm wrote:
Gde... I agree with you it is MOST LIKELY a ground loop. but here is my problem.. Easily gotten around.

In my car, I do not have A/V in on the dash like my daughter does and my motor home does.. I do have a cassette deck however and the fake cassett which lets me play my phone through the cassette system..

Now this is transformer coupled, no direct electrical connection (At least I hope. May lay a piece of tape over the head to isloate and try again).

I get the same kind of noise on the cassette magnetic coupled system I get with the direct A/V The noise I asssoicate with ground loups and common mode interference. in this case using the 120 volt adapter I have and an MSW inverter.. No help.

Run it (The phone) on battery (internal) no noise.

The music is beautiful too. Pange Lingua Gloriosi (Got to learn that stuff before Easter)

Correct.

A tape "adapter" like you have is basically a one for one transformer which may or may not be electrically isolated as far a grounds go.

Pretty simple device, nothing more than a tape player head in the device which when inserted loosely "couples" magnetically to the tape head in the player.

The head coils in the player and the adapter are most likely "grounded" to the shield (ground) wires which can complete the ground loop.

Potentially the head coils could be separated from the outside shell of the head depending on the design, doing so would break any ground loop that may happen when the adapter is inserted.

However in practice I never had any real luck using tape adapters, they just never seem to work all that well for me. Had at one time a 8 track one and a few cassette ones (might even have a cassette adapter in a junk box). While they transferred the audio it never sounded that good and often was picky on how well it seated in the player.

But.. Depending on the phone you have your headphone output may or may not have an additional connection for the mic (after all the main reason for a phone is to talk and many hands free headsets include mics).

So, your phone could have mono audio out and mic in (three pin jack OR FOUR PIN jack), stereo out only (three pin jack) or stereo out, mic in (FOUR PIN jack).

Some of those combinations will require the proper adapter to connect a three pin audio plug correctly...

Although if you have a iphone you might have an optional adapter cable which functions as a break out device as to how that is wired I do not know..