Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Tube DIY Asylum ]

---

[ Alert Moderator ]

---

thank you

Posted by eedork (A) on March 15, 2007 at 18:09:44

In Reply to: Re: single ended EL84 in pentode mode posted by Eli Duttman on March 15, 2007 at 15:52:37:

Eli/Zobosky -

Thank you for the excellent information!

My original goal was to keep the circuit as close to the original (at least using the original components) as possible. As a result, I already punched and assembled the chassis assuming tube rectification (which I've never used before - another learning experiment). I thought about switching to SS rectification, but wanted to try tube since I've done it. Perhaps I should have gone with SS . . . . (maybe on the next rev).

I still have some learning to do regarding pentodes as well. I was not aware that the screen grid was as important as it is. My understanding was that the screen grid in a typical pentode could further increase or decrease the current through the tube, but that it had a relatively small impact compared to the control grid. I need to do some reading.

Regardless, many of the simple SEP circuits that I've been looking at (like the two in the original post) just use a resistor from B+ to provide the screen grid voltage, which is usually a few volts less than the plate. I don't quite understand why this approach won't also work? The voltage won't be as solid as it will be using zeners, but it should still work? I need to research this more too . . . .

Lastly, I have not thought much about the amount of feedback to be used. I was hoping to find and build a simple circuit and learn about feedback in the process. At this point it is a totally foreign concept to me. One of my co-workers (who is much more knowledgeable about these things) tried to explain in to me, but I still don't quite get it.

I need to better understand how much feedback is needed for optimal fidelity and how to design that feedback into the circuit. And just when I had it all figured out for SET circuits without feedback . . . .

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---