Isolation for electronics, why is there no evidence?


Hi everyone,

Something has puzzled me. A very very long time ago I had a Radio Shack phono preamp. Don't worry, it wasn't attached to anything good.  I was probably like 16 or something. Anyway, despite being solid state the preamp was incredibly microphonic. You could flick the thin top and the speakers would ring like a bell.  Clearly something in there was modulating the signal. I've heard since it was probably the cheap ceramic caps, but whatever, something was causing the ringing, and no it wasn't hte turntable picking up the preamp movement.

IN any event, of all the snake-oil like theories of audio one that would seem perfectly testable is finding out just how succeptible a given piece of equipment is to vibration. Put it on the floor, measure the output of music.  Repeat without speakers connected.

Somehow, somewhere we should be able to come up with a way to measure it, and maybe create entirely new classes of products that are not microphonic, or have it be part of regular reviewer testing.  "Why, I love the amplifier, but it measured 0.8 on the Erik scale, so you better get a good stand....."

As I get older I'm getting more sick and tired of equipment that requires so much care and feeding. I want it to be bulletproof and work anywhere, kind of like the Omega space watches.

Thoughts?


Erik
erik_squires

Showing 1 response by whart

I’m not sure this answers any of your questions, Erik, but aren’t there accelerometers or other devices that measure movement in different planes that could be attached to the internals of a piece of gear, an external force of predetermined velocity/mass applied and the impact measured as a physical matter? Assuming that’s all readily available technology that may already be in use (centrifuge or other military/scientific instrument immunity to vibration?), how would you correlate it with sound?
Re tube microphonics, isn’t some of the problem "self-noise," i.e. modulation generated by the tube itself? How would providing mechanical isolation of the chassis or even the tube socket totally eliminate this? I raise this in part based on experience- my Allnic phono stage has gel tube sockets but some of the small tubes still sang sympathetically- you couldn’t hear it through the system, but you could hear it as a mechanical resonance if you were near the unit, had music going through it and muted the output downstream. Simple solution was to replace the tube- Mr. Park, from Allnic, told me the tubes would eventually burn in anyway- they weren’t common small tubes, but ones used for radio transmitting/telephony switching, as I recall.
I had a hell of a time when I used an ARC SP-10 mk ii years ago as my main preamp. The thing was microphonic as hell. I used to go through bags of 6dj8s to find quiet ones- I even had ARC modify the tube sockets at one point to try damped sockets- I forget who made them- it was a third party product similar in concept to the gel socket from Allnic. Didn’t really help, and I had ARC remove the fancy sockets and replace them with their standard parts.

On the bigger subject of "isolation," I also wonder whether using external devices sometimes robs the piece of equipment of its "life."
I’ve certainly messed with various forms of isolation, for different reasons- all of them change the sound to some degree. But, I think your question is directed less to "tweaking" for sonic shadings and more to solving problems like noise that result from unwanted vibration.