mopardave Posted February 9, 2018 Share Posted February 9, 2018 Trying to bias some EH6ca7 tubes i bought off someone on Ebay last year. Got some very hot tubes. After much rotating to tubes a few times i finally got right side to bias at 450, but left side one is 600 and the other is 550. Bias pots are turned all the way down. Been using the pots on far right and left, but there are some in the middle of the board. Can i use use these pots in the center to lower my settings? Here's a pic Quote Link to comment Share on other sites More sharing options...
mopardave Posted February 9, 2018 Author Share Posted February 9, 2018 OK, swapped couple more tubes around and now i can get 3 tubes biased to 550, but one still at 600ma. Looks like i may have to put the old kt77's back in. Quote Link to comment Share on other sites More sharing options...
mopardave Posted February 9, 2018 Author Share Posted February 9, 2018 Switched a couple more around, putting the hottest tube in the socket that had 600mv and every tube biased at 550mv. Not sure i can run these EH fat bottles that hot, but its the best i can do with them. Think the bias should be 400mv Quote Link to comment Share on other sites More sharing options...
mopardave Posted February 10, 2018 Author Share Posted February 10, 2018 Well, that was a bust for sure. Got all tubes biased to 550ma, hooked up all cables, turned on and ran not even 5 min. then all static. Put my JJ KT77's back in biased at 400ma. All good again. I did find something out in all of this thou, measured plate voltage and its 480v. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.