Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1   Report Post  
John L Stewart John L Stewart is offline
Senior Member
 
Location: Toronto
Posts: 301
Default 6LU8 SET or SEUL Amp

I did this one about 12 years ago. It compares very well with what you can do with a 2A3, but at a much lower cost. And 6LU8s are still cheap, all built while production knew how to make a reliable tube.

The distortion tests were done with an HP302A Wave Analyzer for both triode & UL modes at One Khz. Another short set at 100 Hz, One Watt compares Hammond 125E Universal with a Hammond 1628SE. The advantage of more iron is quite obvious.

ULTRALINEAR WITH FEEDBACK WATTS 1 2 3 4 5 6

HARMONIC DISTORTION % 2ND 0.28 0.44 0.45 0.53 0.74 1.18
3RD 0.16 - - 0.35 0.36 0.96
DAMPING FACTOR = 17


ULTRALINEAR WITHOUT FEEDBACK WATTS 1 2 3 4 5 6

HARMONIC DISTORTION % 2ND 2.71 3.93 5.09 6.65 7.71 7.62
3RD 0.70 0.80 1.10 1.20 1.43 4.05
DAMPING FACTOR = 2.3


TRIODE WITH FEEDBACK WATTS 1 2 3 4 5

HARMONIC DISTORTION % 2ND 0.71 1.04 1.30 1.66 1.98
3RD 0.22 0.25 0.49 0.50 0.79

TRIODE WITHOUT FEEDBACK 2ND 3.95 5.83 7.11 8.93 8.83
3RD - 0.23 0.21 0.20 2.07

Following measured at 100 Hz

OUTPUT TRANSFORMER 125E 1628SE

A) ULTRALINEAR WITHOUT FEEDBACK

HARMONIC DISTORTION % 2ND 15.3 2.9
3RD 3.1 0.4

B) TRIODE WITHOUT FEEDBACK

HARMONIC DISTORTION % 2ND 12.2 2.8
3RD 1.5 ---

Hope this comes out your end OK. Cheers, John
Attached Images
 

Last edited by John L Stewart : March 16th 11 at 05:21 PM Reason: Problems with tables
 
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT +1. The time now is 09:21 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"