OK so i completed a new Rocket build over the weekend.  I posted some details about it a while back.  It is in a custom chassis.  The chassis is the a Blues Junior style and will fit a custom cab I have.  So basically a rocket circuit in a custom Blues Junior cab and chassis.
  In any case the issue is that I used a PT that has a bit too much voltage.  over 390 at the plates and about 385 at the screens.  I am having issues with red plating.  I used the standard 50ohm 25 watt cathode resistor. Is it possible to run EL84's at this voltage with a larger cathode resistor? 
Here are some pics.
[IMG:600:800]http://i14.photobucket.com/albums/a330/HeeBGB/Rocket/IMG_3224_zps68d6adf1.jpg[/img]
[IMG:600:800]http://i14.photobucket.com/albums/a330/HeeBGB/Rocket/IMG_3223_zps53d62559.jpg[/img]
			
			
									
									
						New Rocket Build Bias Resistor issue
Moderators: pompeiisneaks, Colossal
Re: New Rocket Build Bias Resistor issue
The standard 50 ohm could be too much even with proper voltages so increase it to @ least 80ohms and see what happens!!
Good luck!!
			
			
									
									
						Good luck!!

Re: New Rocket Build Bias Resistor issue
Thanks.  Can I get away with a lower wattage resistor?  The one called for is 25watts.  I have a 100ohm but only 10watts
			
			
									
									
						Re: New Rocket Build Bias Resistor issue
Not so sure about that!! 
			
			
									
									
						
Re: New Rocket Build Bias Resistor issue
If you want to try it, I have a pair of cement 200 ohm 10W resistors that you can try out (just don't cut the leads please). You can parallel them for effectively a 20W 100 ohm resistor. Should be close enough.
			
			
									
									
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Re: New Rocket Build Bias Resistor issue
I know there are several posts regarding using the higher voltage tap on a "standard" Rocket PT... seems like it was first brought up by either Allyn or 2-Tone. They settled on a 68 ohm bias resistor when using the 280v tap. I think this would keep things right on the ragged edge where VOX designed them to operate - for better or worse. 
As mentioned above, 100 ohms is probably close enough and your tubes would thank you while your fans would never really know...
			
			
									
									As mentioned above, 100 ohms is probably close enough and your tubes would thank you while your fans would never really know...
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