In this video, we will compare the sonic differences between 11 types of power tubes in a single-ended guitar amp: 5881, 6L6GC, 6V6GT, EL84, EL34, 6CA7, KT66, KT77, KT88, 6550, and 7581A. Below is a link to a free .pdf to take notes to help evaluate each tube.
www.insideoutguitar.com/wp-content/uploads/2023/08/Power-Tube-Evaluation-Form.pdf
I highly recommend doing this comparison in a critical listening environment as some differences can be quite nuanced.
Clean amp examples:
2:44 7581A
3:10 EL84
3:36 6V6GT
4:02 6L6GC
4:28 KT66
4:54 EL34
5:20 6CA7
5:46 6550
6:12 KT88
6:38 KT77
7:04 5881
"Edge-of-breakup" examples:
7:49 7581A
8:19 EL84
8:49 6V6GT
9:19 6L6GC
9:49 KT66
10:19 EL34
10:50 6CA7
11:20 6550
11:50 KT88
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