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In the Forum: Audio Discussions
In the Thread: Initial thoughts about new/old Lamm ML2s
Post Subject: New cause/cure for switch-on pulsePosted by Paul S on: 8/11/2008
Just wanted to report that less-than clean 12AX7 pins can cause a switch-on pulse through the speakers just like bad 12AX7s can do. I think it's been about 18 months since I cleaned these, when I first installed them, and I just was not ready to believe that NOS Tele 12AX7s went bad after only 18 months. This happened yesterday.
Today, I was getting a faint "crumpling plastic wrap" noise from the right speaker. I was able to exacerbate it by SLIGHTLY moving the (new/clean!) 6N6P (don't try this at home!!!).
I turned off the amp and waited for the caps to drain, then I pulled the 6N6Ps, straightend the pins and carefuly reinserted them. It worked fine, with great music all day, until the electricity went south, around 7 PM.
Reminder to self: Keep all tube pins/sockets and other connections clean, including long-lived tubes, which should probably be cleaned once a month or so, or more often in ocean front and/or humid environments.
It's hard enough to get good sound from a properly-operating system. It's impossible with bad connections.
Paul SRerurn to Romy the Cat's Site