Help, Phantom Distortions and Stumped Again
Another weird audio mystery...why does this always happen to me?
Friday there is a very unpleasant distortion coming from the midrange on one of my speakers and, to a much lesser extent, the other one as well. Thus ensues the lineup of the usual suspects. No on the CDP, the preamp, clean all the connections, then switch the channels and even run the speakers on another system entirely and the distortion remains the same – looks like a bum driver (and it's the finicky Thiel coaxial, so I figure that's my culprit). Sounds simple, right? But wait.
The amp in question is a Bryston 4b-st that has been having trouble with its muting switch. Which is to say that, at power down, it bleeds current into the speakers, prompting them to do a rather nasty crackling routine. Not good. So, I figure it was the amp that damaged the midrange driver. Again, sounds simple, right? But wait.
Sunday I decide to try again (with the speakers still in the second system - the Bryston is officially sidelined until it gets back from the doctor). Perfect. No distortion, no problem. To add insult to injury (or the lack thereof?!) without all of the tubes and tweaks, running off of a Marantz HT receiver and a DVD player, the Thiels sounded pretty good. Not great, to be sure (OK, a lot less than great) but a lot better than I expected.
What gives?!? The best I can come up with is that the amp may have left some lingering nasty charge in the midrange driver that produced the distortion, even while running off of a completely different amp (is that even vaguely possible?). However, couple of days later, the charge has dissipated and the driver is healthy again...? Any thoughts? (I'm not making this up, I swear...).