Failure

While working in my office today I suddenly realized that the music had stopped. Looking at the Source Selector Preamp showed that the output levels were not moving. A little investigating revealed the culprit.

Remember back in the beginning of January when I traced the failure of the Lacewood amplifier to a failed JJ power tube? Well, here we go again.

After a busy Christmas season, including a brief trip out of state between Christmas and new year, I have finally managed to get the Lacewood amplifier back up and running. As part of this effort I also identified the root cause of the initial failure. And frankly I’m a little angry about it.

Remember a few weeks ago in the post When it Rains, It Pours! I said that the Lacewood V2 reservoir capacitor had likely failed? Well, I was wrong.

Would you believe it? Today while listening to the 6V6 Lacewood V2 I heard a funny little popping sound and a short duration whine. It only lasted a few seconds, then it was gone. But when I walked over to the amp there was a distinct smell of “magic smoke”. Once again, the game’s afoot!

I have witnessed a lot of electrolytic capacitor failures. Most of these failures have occurred from improper wiring polarity or a significant over voltage condition. They generally involve an explosive emptying of the capacitor shell. These failures usually leave a smoking husk of a component and a spray of foil bits, dielectric insulation, and liquid electrolyte spewed across the circuit, chassis, and sometimes, the test technician. But recently I came across a much different failure. One which seemed to be specially concocted to sneak by without notice.