The PROPER way to TUNE a tube amp?

[Master Chief 516]

I actually have a couple of questions:



Back in the day, you just tuned "load" and "tune" both for max and called it a day. We didn't know what we were actually loading and tuning, but its what we were told to do. It always worked right up to the point that the tube(s) failed!



The Pride DX-300 manual says to "...peak the PLATE TUNE control for maximum...". Then you are supposed to advance the PLATE LOADING control a 1/2 a division and peak the PLATE TUNE again. This goes back and forth until you reach maximum smoke. Finally, they state that the final tuning is always done with the PLATE TUNE control.



Nowadays, everyone seems to have a radio that "swings". Some people tune with just a dead key while others tune with audio into the mic.



Question #1:

Dead key or audio; and why.



Question #2:

If you want to throttle your amplifer down, but don't have control over the input wattage, can your back off on the LOADING or will this hurt the tube?



What is the PROPER way to tune an amplifier and why?



Dino


</p>

 

[Moleculo]

The pride doesn't have plate current and voltage meters. So the only real way you can do it is by judging with the watt meter.



Most responses have answered the question. But there was one question I didn't see answered: Lowering the Load to decrease power is a BAD idea. In fact, you could damage the amp if you do this. Improperly adjusted loading causes high tank circuit voltages.



Also, for proper linearity, the load should be increased so that it is increased just past the maximum power output. So you adjust for max, then increase just a little to bring the power down a bit. The load control is the most important control for good linearity.


</p>

 

[Lazybones1222]

How about the three knobbers like my Varmint. I have a driver plate cap knob too.



I do all 3 for max dead key then tweak the final load to peak with audio. When I do that it brings the swing way up and drops the deadkey. I get 100 swinging to 400 - 450 watts depending if the tv is on or not......same wall circuit. haha

</p>