Home Tube DIY Asylum

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

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Tube DIY Asylum ]
[ Alert Moderator ]

RE: I'm with Tre' on this one

"The front end was engineer designed to work with a broad range of tubes."

You have missed my point. If the circuit was designed to "work" with a broad range of tubes, then that means it will not get the best out of any of those tubes.

To get the best out of a particular tube, the circuit has to be fine tuned for that particular tube. So a design that will "work" with more than one particular tube is not optimized for any particular tube and therefore not getting the best from any of the tubes.

The designer's posted load lines below prove my point.

See what I mean? He's running a 12au7 at less than 2ma idle current and 67 volts plate. There is nothing optimized about that operating point.



The 12ax7 is being run at about 1ma and 155 volts plate (wrongly marked as 127 vdc). That's not bad but the 100k load impedance is too low so the load line is more vertical than it should be cause the tube to produce excess harmonic distortion. There is not anything, design wise, he can do about it. If he increases the plate resistor value, then the 12au7 wouldn't work at all.



All around this whole thing is just an awful design.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"


Edits: 11/21/24 11/21/24 11/21/24
This post is made possible by the generous support of people like you and our sponsors:
  Kimber Kable  

Follow Ups Full Thread
Follow Ups
FAQ

Post a Message!

 Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.

[ Top 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 ]