K&K Audio / Lundahl Transformers

Welcome! Need support, you got it. Or share youe ideas and experiences.

Return to K&K Audio / Lundahl Transformers

Message Sort: Post Order or Asylum Reverse Threaded

LL2734 helo please

71.63.70.121
Posted on April 24, 2014 at 13:29:49
dirkwright
Audiophile

Posts: 10
Location: United States
Joined: May 11, 2011
 I'm interested in using the LL2734 for an unintended use. It appears to be designed to replace a Neve product for single ended solid state circuits. I want to use it as the output for a 6GK5 vacuum tube in a line level stage. The tube runs at about 10mA and has a plate resistance of 5,400 ohms. The data sheet for this transformer lists the inductance at 1.0 H (I assume at 100mA?), which is pretty low for a tube output transformer (even in a line stage like the intended use). Is this transformer going to develop enough impedance to allow the tube to work into something higher than 5,400 ohms (10,000 ohms would be better)? I like this transformer because it has a feedback winding which I could use with the cathode of the tube. Any help is appreciated.

 

Hide full thread outline!
    ...
RE: LL2734 helo please, posted on April 25, 2014 at 08:28:00
Tre'
Industry Professional

Posts: 17305
Location: So. Cal.
Joined: February 9, 2002
 It sounds like you already understand the following,

The reflected impedance at the primary of a transformer is determined by the impedance ratio of the transformer and the load presented to the secondary.

The reactance of the inductance, at the low frequencies, will dominate the impedance seen by the tube driving the transformer.

For that reactance to be 10,000 ohms at 20Hz there needs to be 85Hy of inductance in the primary.

I know nothing about the LL2734 but if it's inductance is stated at 1Hy, I doubt that it will have 85Hy under any conditions.

But, of course, I could be totally wrong.

Tre'


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

 

RE: LL2734 helo please, posted on April 25, 2014 at 08:54:00
KevinC
Manufacturer

Posts: 2984
Location: NC
Joined: April 19, 2001
 Per Lundahl estimates that the LL2734/10mA would have a primary inductance with the 1.4 windings in series of something like 10H, not even remotely enough for your project.

Kevin Carter
K&K Audio
www.kandkaudio.com

 

Page processed in 0.015 seconds.

[ 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 ]