RH84 bias change whith different el84 is use

tim614 · 26th June 2009, 04:24 PM

My RH84 bias (cathode bias) was dial in at 11.6 plate disipation with a pair of JJ but when
i bought a new pair of TAD el84 to try out now my bias is way up at 12.55watts plate disipation.
can some one explain why its doing that?

bigwill · 26th June 2009, 10:23 PM

All tubes have slightly different parameters, that also drift with their age. This is why a lot of amplifiers have bias adjustments.

26th June 2009, 04:24 PM	#1
tim614 diyAudio Member Join Date: Jun 2008	RH84 bias change whith different el84 is use My RH84 bias (cathode bias) was dial in at 11.6 plate disipation with a pair of JJ but when i bought a new pair of TAD el84 to try out now my bias is way up at 12.55watts plate disipation. can some one explain why its doing that?

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26th June 2009, 10:23 PM	#2
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	All tubes have slightly different parameters, that also drift with their age. This is why a lot of amplifiers have bias adjustments.

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