Home » Audio » Thermionic Emissions » Looking for good 20 watt amp design to drive Jordan TL's?
Re: Damping factor - SE vs. PP [message #11234 is a reply to message #11233] Fri, 14 October 2005 09:55 Go to previous messageGo to previous message
Steve is currently offline  Steve
Messages: 83
Registered: May 2009
Viscount
Right, we are talking dynamic Ra, and keeping the power as low as possible is crucial/fundamental for keeping Ra relatively constant, although never as good as PP. (I think that is one reason I have been hearing suggestions of using Even higher efficiency speakers.)

rp= u/gm, both u and gm constantly change during a cycle. Both changing independently, not in sync, in value and causes rp to rise.

This can be graphed in a quadrant. The Ra curve (at different plate voltages) rises gradually at first over the first 5 volts peak or 10 volts p-p; then rises rapidly. Even then, a 10 volt peak, 20v p-p, drive signal can easily cause Ra to change by 20% or more over a cycle. The slope of the loadline is very important. A more vertical loadline dramatically increases Ra's change and effect. A more horizontal loadline helps minimize, or even eliminates Ra changing. But a horizontal loadline causes the output power to lower, rather dramatically.

This applies to any triode run SET mode. Just something to think about when designing an SET amp. RL is important.



 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Polarized non-polar caps
Next Topic: Need 15 watt plus SET design for DIY?
Goto Forum:
  


Current Time: Sat Dec 14 14:32:53 CST 2024

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Miller Audio
Miller Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest