TS-830S Driver tube
I noticed my TS 830 S is putting out 25 to 30 watts less than my TS-520S for same freq.. It seems like the drive is lower when I tune up.. I have a replacement drive tube.. Can I change it out with out worry about any other adjustments.. I will leave the final tubes alone.
Yes, you can just swap out the 12BY7A and leave everything else alone, neutalization is not required as it is with the finals. But since you have to pull the cover anyway, I'd see about peaking the driver coils in the coil pack before swapping out the driver tube.
You can get an indication of how well the driver tube is doing by noting the max ALC you can get. a weak or failing driver tube will show an ALC level that decays as the transmission continues.
However, another check is to turn up the CAR control and see if more is required to give a higher CW output. It is normal for higher frequencies to require a higher CAR setting, and different driver tubes could as well.
The 830 is rather prone to filter caps becoming leaky and dragging down the various B+ voltages, especially the final plates. That can be monitored on the meter at about 900V in standby and 800+ at full 100W out.
You would do well to download the information on the TS-830S at this site; http://www.n6wk.com/kenwood/.
Some very good information.