Although the feature has been deleted from newer models, there was a time when Amazon’s Echo devices included a 3.5 mm “aux” input jack that let you connect other audio sources to the smart speaker. Alexa would even let you switch over to an external source with a voice command — or at least, it used to.
As first reported by Reddit user [n8-sd], Amazon has started informing users that voice control over the 3.5 mm jack is no longer supported. While the physical input will still function on models equipped with it, if you want to mute the audio coming from an external device you’ll have to wade through the Alexa smartphone application to do it.
In a statement to Ars Technica, an Amazon rep confirmed that voice control over the auxiliary input has been removed as of the latest software version, and that their analytics showed not many people were using the feature in the first place. They also pointed out that no changes have been made to voice control of Bluetooth devices. While we don’t doubt that the total number of users that were physically plugging an audio source into their Echos was probably low in the grand scheme of things, that doesn’t really explain why such a simple feature needed to be actively removed.
Some commenters have theorized that the real reason behind the change is the fact that Amazon has no way of monitoring what users are playing over the auxiliary input. Since cataloging and selling the media consumption habits of users is big business these days, that’s a problem. While they might prefer to disable the feature entirely, they know that would stir up some bad press, so they’re opting to simply make it more annoying to use. We’re not saying we entirely buy this explanation, but it’s not the craziest thing we’ve ever heard either.
Although the Echo devices have never been particularly hackable, they have enjoyed a certain amount of success with tech-savvy users, making it all the more disappointing to see the ecosystem seemingly becoming less capable over time.
For a little while vacuum tubes and semiconductors were fighting a heated battle for dominance, with bipolar junction transistors and 1959’s RCA Nuvistor both allowing you to build a compact circuit with relatively low power usage and no high voltages. Although we now know that semiconductor technology won out overwhelmingly, that doesn’t mean that you cannot build a brand new Nuvistor board in 2026, 
