Home OTL Asylum

OTL, Output Transformerless Amplifier User Group.

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

Micheal Rothacher understands Class A

This is from the MosFet Circlotron pdf from the link you gave.

Micheal Rothacher understands Class A.

"How much bias current will we need? This amplifier will be conservatively rated for 20 Watts @ 8 Ohms in Class A, so our peak output current will be 2.24A (1.414 * SQRT(20/8). So, we’ll need to set the bias for each output MOSFET around one-half of this value, and we’ll round it up to 1.2A DC."

This is what can't be done in a Circlotron using 8 6as7g's driving 8 ohms above about 5 watts.

One cannot set the idle current at half the needed peak output current to make 60 watts into 8 ohms.

At the idle current normally used in a 8 tube Circlotron OTL the current can only be driven down (as much as up) to an output level of about 5 watts.
If driven to an output wattage above that the "flat spot at the bottom of the curve" starts to show up.

The current in Micheal's output devices can be driven down as much as they are driven up, to the full rated 20 watts, with out creating that "flat spot at the bottom of the curve".

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


Edits: 08/24/11
This post is made possible by the generous support of people like you and our sponsors:
  VH Audio  

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 ]