Sovtek 5881WXT Power Vacuum Tube (Matched)

Hi, with all respects, I replaced old Sovtek 6l6s 30W versions for these, but Groove Tubes versions 1 year used and pulled from Fender tube combo (not sure what model they put them in) in my Guyatone Bassman 1100-DB and they perform great, everyone should know these are russian NOS tubes and when perfectly matched, they last longer than any other 6l6s I know. My tech measured 124 Watts on the output with matched quad so Its really strong tube we are talking about. I would say they open their sound best when they are adjusted on the hot side rather than cold. These old Fender silverface/blackface amps are tube eaters and these Sovteks are great for them if you want your tubes last. I can recommend them and make sure you have good 12at7 at PI, like I did (NOS Mullard) and good 12ax7s in other stages. Because not only power tubes make your amp sound good but I hear preamp tubes making much bigger difference. That is my opinion after couple years of playing through a tube amplifiers.

I’ve got them in my fender De Ville 2 12 and they sound great in any channel, no noise at all or popping and the clarity is very predictable depending on your tone selection . I will experiment with others later with jj’s and EH’s but for if it doesn’t hiss or pop, why change anything when you’re happy with them, I give them a 5 rating for sure!

these tubes really frustrated me. I put them in a VHT along with trying different tubes, speakers ect... after going piece by piece on why my amp sounded terrible I found these where the culprit. do not buy these if you are serious about your tone.

The owner of a repair shop recommended these for my 5150 head. Great sound and performance. I used JJs for over 10 years but I prefer these tubes.

I used 5881WXTs in my Sherwood C300 mono integrated amp. The amp developed a strange problem - intermittent hum. I would turn it on and it would be fine for 5-10 minutes. Next I would hear a click or pop, then hum. Everything worked; it just hummed. I had recapped the unit. However, I rechecked every cap anyway with an ESR tester (all good). I started thinking about H-K (heater-cathode) shorts. I replaced every tube in sequence (two 5y3's, followed by 12at7s and 12au7s). No change; still started humming after a 'pop'. Then I replaced my six month old 5881s with a pair of Sovtek 6L6WGCs. After two hours of continuous play, no more 'pop' and no more hum. Looks like at least one of my 5881s had an H-K short. Odd that this did not show up on my Eico 667 or Mighty Mite testers. I guess the only way to be sure is through substitution. Conclusions? Great sounding tube. Failed after 6 month's casual use. Out of warranty of course.