Legacy Wireless Tether “Noise”

I've never seen that.  I just checked four Legacy steam engines of various vintages that were on the TT, none of them exhibit any such behavior.  This sounds like a local issue that isn't within the engines to me.

I'd say it's perfectly normal.

What likely is happening is, your tender is booted up in command, but is silent from not being commanded. By silent, I mean no commanded sounds to be played- however- the sound amplifier section is enabled and on. Most likely, also set at the highest possible volume or gain. Keep in mind, all of this is on a regulated DC 5V logic bus including the IR tether receiver. Because data commands are bursty and well within audible range, it's not impossible that there is some cross talk on the ground plane, the amp being max gain picks this up and out the speaker it goes when not masked by actual sounds from the railsounds processor analog output.

While we can say all day long that should not happen from a good design, well right there is your answer. Perfect silence was not a checkbox requirement.

@casconi posted:

I have two Lionel Legacy steam engines …

while my layout was powered on (20v to track via Powerhouse)

As a side note, max recommended voltage for Lionel equipment in general I thought was agreed to be 18V AC and no more than 19V in many manuals. I'm not saying this is the cause of the sound, but just an observation of what I consider a good rule for longevity of your Lionel equipment being broken.

I'm not sure I'd consider it normal, I tried four locomotives and all were perfectly quiet until I started them up.

You can actually hear a little background white noise sound from some TMCC stuff.

FWIW, I know I have heard and seen some of the older Railsounds power boards with the large chokes on them make audible noises with voltage present on the track.

So, we are kinda back at the typical- what 2 specific engines are we talking about? What are the Lionel product numbers? 6-XXXXX

Correct, the older RS boards did have a lot of background noise, that was pretty constant.  I don't remember having or not having the serial link making a difference.

I just tried a RS5 TMCC model, dead quiet.  Then I fired up a RS4 equipped model and there is background noise.

There is also an issue with certain Legacy sound files, I know the Vision Line Genset is one that had some background noise.

I've heard some of the newer legacy steamers make an s.o.s digital sounding noise when power is to the track but the loco itself has not been addressed.  Some of the older ones make a faint steady electronic noise.

FWIW. The freightsounds reefers do it as well.

It isn't heard during loco operation.

I suppose it depends on ones hearing, it certainly isn't very loud. Imo it's comparable in volume to the high pitch that can be heard from Miller signs. Although, once you hear it. You always hear it.

I believe this has come up before and is  considered normal. If I recall correctly.  A forum member even posted video on the previous thread.

If it ain't broke,don't fix it.