Hello all. Suppose i wanted to forgo UL connection to output tubes and instead connect an independent regulated screen supply. Other than paying attention to the voltage (as directed on a data sheet) is there anything else to consider? Thanks for any helpful input.
I'd still use a small series resistor at each screen to act as a fuse in the event of tube failure.
Roughly 100R at 1W to 2W.
Roughly 100R at 1W to 2W.
Of course you terminate the UL taps/leads so they don't flop around and short-out B+ through the OT.
Yes, I attach a two lug terminal strip to the nearest tube socket mounting screw,
and use that to solder and support the resistor, and run a jumper wire to the tube socket lug.
and use that to solder and support the resistor, and run a jumper wire to the tube socket lug.
Good to support, and have, the added resistor.
But such changes often leave two output transformer leads "idle", floating. I have seen builders just tuck them into a corner. Unless taped or secured, the ends may short to chassis.
Very helpful tips. Yes, of course i would be careful to properly isolate and secure the unused UL wire.
Go ahead and try the switch from UL to pentode/beam power mode.
The damping factor, distortion, and power will be different, especially if you are not using Schade or global negative feedback.
A good listen will tell you a lot.
You may find that one or more of these parameters may need to be changed to get optimum performance in your system:
output transformer primary impedance, plate voltage, and plate current may be different in pentode/beam power than for UL operation.
Happy experimenting, Happy listening.
The damping factor, distortion, and power will be different, especially if you are not using Schade or global negative feedback.
A good listen will tell you a lot.
You may find that one or more of these parameters may need to be changed to get optimum performance in your system:
output transformer primary impedance, plate voltage, and plate current may be different in pentode/beam power than for UL operation.
Happy experimenting, Happy listening.