May 3, 2021 · It is a two stage amp that runs a pair of pentodes with direct feedback from the plate to the control grid to generate triode curves from a pentode. Tubes that have low screen grid voltage requirements can be used since the screen supply is not required to be at plate potential.

The single-ended (SE) power output stage is the simplest form of power amplifier. It is basically the same as an ordinary gain stage, but instead of a load resistor we use an output transformer. Single-ended amps are usually fairly low power (less …

Dec 1, 2008 · I've got this amp set up with a switch for Ultralinear/Pentode/Triode mode. I also have a switch for changing the bias resistor value depending on which tubes I'm running. I've run the standard KT88's, EL34, 6CA7, 6L6G, & KT66's.

Sep 9, 2014 · Instructions to build a Single-Ended (SE) 6L6 / 5881 Vacuum Tube Amplifier. Power output is about 10 Watts in class-A operation.

May 14, 2005 · The 50EH5 is a miniature power pentode which was primarily designed and widely used in the audio power output stage of radio and television receivers and in phonographs. The tube features high power sensitivity at low plate and screen voltages.

Apr 12, 2023 · I am considering to use Siemens F2a tube in pentode mode as SE output. However all schematics and load lines that I could find online use F2a triode strapped (which is perfectly fine, but this build I want to experiment with pentode).

Jan 12, 2012 · The EL34 data sheet shows that a pentode connection with lower plate voltage than a triode connection produces more power ( 3w more if I remember ). Most amps I have built have their power tubes screen grid at the same potential as the plate, and then are being considered as triodes.

How to make a triode out of a tetrode or pentode again? Or, what to do with the “superfluous” grids?

I designed it for use in a SE amp using the rare 4304CB / VT-62 / or 834 triode. It can be used in many different applications, even in class A1 use, though it is optimized to drive grid current, and for use with loop NFB. The circuit uses a single 2-section tube that has a triode and pentode.

The 813 is a ~100W pentode designed for radio transmitter and modulator service, and was used in the WWII timeframe, I think. It was a common tube in smaller AM broadcast transmitters, especially as a modulator.