|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
69.250.235.103
In Reply to: RE: 7189 and 6BQ5 - Plate Voltage and Dissipation posted by FlaCharlie on July 29, 2016 at 10:57:33
The RM 10 runs its 6BQ5s at over 600 volts on the plate and 300 on the screens. The key is to keep the idle current low so you don't reach the max plate dissapation ratings.
Follow Ups:
Not sure how this works, at a 300VDC difference.
Thanks!
The difference is due to the screens running off a separate B+ supply. A separate screen supply is the best way to operate a pentode.
Not only separate, but regulated .
Screen grid to cathode potential, not plate to cathode potential, dominates in pentodes and beam power tetrodes. Regulation of g2 B+ reduces the amount of open loop IM distortion generated. NFB, of whatever form, works best when it has comparatively little to do. NFB, of some kind, will always be needed with pentode mode "finals" to realize an acceptable damping factor. However, less is definitely more, when it comes to open loop distortion.
FWIW, the most effective implementation of ultra-linear (UL) mode "finals" requires O/P transformers that contain a separate screen grid winding. That separate winding allows g2 B+ to be regulated and benefits from more than 1 source obtained.
Eli D.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: