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I was wondering if anyone has done a comparison of the 6SL7 vs 6SU7. Any input would be appreciated. I will probably try both.

6SU7 is a totally different tube than a 6SN7, although I can't find much difference between a 6SU7 and a 6SL7, other than their pinouts are different.

6SN7
Plate voltage 250
Grid voltage -8
Amplification factor 20
Plate resistance 7,700 ohms
Transconductance 2600
Plate current 9 ma.
Plate dissipation 2.5 watts

6SL7 6SU7
Plate voltage 250
Grid voltage -2
Amplification factor 70
Plate resistance 44,000 ohms
Transconductance 1600
Plate current 2.3 ma.
Plate dissipation 1 watt

If you want to try a CHEAP single triode 6SL7, try a 6AQ7.

6SU7's go for stupid on Ebay at times, too

N.O.S Tung-Sol 6SU7's $35.00 ea.
http://www.vacuumtubes.net/RES%20Audio% ... /6sn7.html

NOS 12SL7 $4.15 oldradioparts.com

NOS 6AQ7 $1 in 10 pack ESRC.com

hilldweller wrote:I was wondering if anyone has done a comparison of the 6SL7 vs 6SU7. Any input would be appreciated. I will probably try both.

According to the spec sheet, the 6SU7 was designed for better balance between sections. If both sections are cascaded, it probably doesn't make any difference. As an LTP with active tail loading, maybe the 'SU7 will show less DC offset, but otherwise, not any great difference there either.

It might be more critical if used as a floating paraphase, or with passive tail loads.

Impmon wrote:

hilldweller wrote:I was wondering if anyone has done a comparison of the 6SL7 vs 6SU7. Any input would be appreciated. I will probably try both.

According to the spec sheet, the 6SU7 was designed for better balance between sections. If both sections are cascaded, it probably doesn't make any difference. As an LTP with active tail loading, maybe the 'SU7 will show less DC offset, but otherwise, not any great difference there either.

It might be more critical if used as a floating paraphase, or with passive tail loads.

Many thanks! Very helpful info