The OP made comparison of the TS 7581 tubes to, among other tubes, the KT88's in his first sentence. So far as I know, few tube amps can swap between EL 34's and KT88's. I am super happy with the pricey Shaguang KT-88-t tubes in my Don Sachs power amp. They are much better than the Gold Lion KT88's, which are also very good.
Really...My favorite power tube is reissue that's not widely popular
If you run 6l6/EL34 variants, I HIGHLY recommend trying this tube out. The Tung Sol 7581A reissue. I've had these for a good bit of time and compared them against KT150s, EL34s (several brands), KT88s, and maybe another that I'm forgetting. They are a mere $30 a pop and they are the best tube I have heard. I know that's a brave bold statement to make as there is so much competition out there and the tube is very much under the radar from what I can tell.
After having these around for a long time (and in and out of the amp), I had them in and was nearly spellbound one night by how great they sounded upon reentry into my amp. I did a search and could only find one review, which I agree wholeheartedly with. You can find it here: https://wallofsound.ca/audioreviews/amplification/6l6-vacuum-tube-review-tubes-courtesy-of-www-thetu...
I am nearly incredulous there isn't hype out there about this tube. Simply my favorite tube. I thought I'd pass this along as it may be much cheaper to give them a whirl then fuss with a much more expensive power cord, cable, or other tweak.
After having these around for a long time (and in and out of the amp), I had them in and was nearly spellbound one night by how great they sounded upon reentry into my amp. I did a search and could only find one review, which I agree wholeheartedly with. You can find it here: https://wallofsound.ca/audioreviews/amplification/6l6-vacuum-tube-review-tubes-courtesy-of-www-thetu...
I am nearly incredulous there isn't hype out there about this tube. Simply my favorite tube. I thought I'd pass this along as it may be much cheaper to give them a whirl then fuss with a much more expensive power cord, cable, or other tweak.