Two amps have "died", no sound, what could this be!?

[Beardguise]

This has remained a complete mystery to me for multiple years now.

For years I've had a basic Onkyo TX-8211 tuner/amp set up with a pair of KLH 17s. Life was peachy (and both of these are still kicking).

I got my hands on some new gear, all seemed to be in good working order, so I moved the Onkyo to another room and the main setup became a pair of Snell B towers with and Audiosource Pre One & Amp One.

This worked great for quite some time, until one day the amp one simply stopped producing any sound. Tried with other speakers, nothing. I've since moved the Audiosource stack on, so I can't dig into that part of the story.

I added a Kyocera R-861 receiver into picture, and the same story follows: it worked great for a while, and then at some point the amp just stopped outputting sound. Tried other speakers, other cables, no luck. I still have this setup around, so if there's any minor poking around I can do to diagnose, that might be possible. I don't have much in terms of tools beyond a multimeter (and I'm certainly no expert with it). At this point, it hasn't worked for well over a year and I have no idea what to do.

In an attempt to provide as much context I can think of (for what it's worth), these units were both plugged into the same outlets and I believe a microwave in a different room behind the setup is wired on the same circuit. When I used to have an analog TV near all of this gear, I'd sometimes see a line or something in the picture when the microwave was running. I don't remember there being any issues at all with the Onkyo, and I believe I added the microwave to that circuit before ever getting the Snells.

Any idea as to what could possibly be going on here? How might two amps die, seemingly the same way? They're both rated for plenty of power @ 8Ω for these Snells. I'm completely at a loss. Let me know if there's additional information that would help.

Thanks in advance!

 

[Thud3]

So they power-up, but won’t make sound? From any source? Like turntable, CD, aux. input, etc?
No tape monitors or mute functions accidentally activated?

 

[nj pheonix]

Not a lot of background story. I can throw out some guesses. The Snells have an issue that's killing the amps. The speaker wire you're using for the snells have an issue (pinched, nicked, loose strand on either end.) You have some kind of electrical issue in the house open neutral(?) causing high or low voltage damaging gear. Coincidence(?) someone in the house is sabotaging your gear.

 

[Beardguise]

Thanks for the replies, folks! I've done some tinkering around and what I thought was going to be "sanity-checking", set up the gear again, and it turns out the Kyocera actually isn't completely dead!? I must've mis-remembered from the last time I looked at this stuff.

Sound plays through both channels through both sets of speakers using the A/B selector on the Kyocera. Great success, right?

Wrong. After listening to an album for ~30-40 mins on the Snells, I heard pops coming from the speakers while sound was playing. The noises aren't particularly loud, they're no louder than the music anyway. They almost sound like a button snap? Listening closely, I think the pops came from the lower of the two 5" woofers? I'm pretty sure it happened in both channels, unsure if it happened more in one or the other.

A few things I should try:

• Reproduce this on the Snells, double check it happens on both speakers
• Try to reproduce this the KLHs (effectively isolate the issue to the amp)
• Try to reproduce with no audio playing, just with the amp turned up to normal gain