nadolskib Posted April 11, 2016 Share Posted April 11, 2016 Hi Guys, I know there is probably a lot of different posts on this topic already but I'm finding different answers everywhere I look. So this is my very first tube amp and I've have had it for around 5 years or so and never needed to replace the tubes in it until now. About a month or so ago, the amp started to randomly crackle while I was playing and and I noticed that when it did crackle, the one power tube would flicker. Now if I try to use that tube at all, it red plates after the amp is on for a few minutes and if I switch tubes, the same tube red plates so I know it has to be the tube that is bad. I also took my pre-amp tubes into my local music store and was able to get them tested and my one pre-amp tube has a bad plate in it. So in the end, I'm thinking of just replacing both pre-amp tubes and both power tubes. Now from what I've read so far, the power tubes need to replaced together as a matched set and need to 6L6s while the Pre-Amp tubes can be replaced individually just as long as the are the 12AX7s. Now here is where my questions come in at, do the power tubes have to be replaced with the Sovtek 5881/6L6WGC tubes or will any 6L6 tube work and does it have to be the 5881 version? And also do the pre-amp tubes have to be replaced with the Chinese 12AX7-B or will any 12AX7 work? I was told by a good friend of mine that Mesa Boogie Tubes are pretty well built and have a solid tone to them so I was thinking about just getting the their 6L6 STR-440s and either 12AX7s or the SPAX7-A for the pre-amps. Any and all information will be greatly appreciated. As I mentioned before, this is my first tube amp I've ever bought so I'm learning all of this new information for the first time. Now I do know that once I get the power tubes, I need to re-bias them which I've already learned how to do thanks to the wealth of information on the internet. I'm also kinda curious as to why my one current tube would be red plating regards if I put in the V3 or V4 sockets? I know very little about tubes so I don't know if its the cathode resistor or grid resistor (if either of those two things exist in a tube) that crapped out or if it might be something else in the tube. I know this isn't really important to know but I've just one of those people that likes to obtain as much information and like to learn how things work and operate. Quote Link to comment Share on other sites More sharing options...
psarkissian Posted April 11, 2016 Share Posted April 11, 2016 Mesa, Groove Tube, JJ's,... fine tubes. Just not in a Bogner designed amp. These are hybrid amps with both analog/digital with tube and solid state components. These are not the tube amp of the 1960's yester-years where you can swap tubes willy-nilly and have it work. These amps are very particular. Stick with the specified tubes. Those are the Sovtek 5881WXT Matched Pairs with the cup based bottom, Chinese 12AX7B is good. They are not designed to handle substitutes. I see too many come across my bench with substitutes, and incorrectly biased power stages,... so they come to me blown and not working because of it. You can't get away with the same kinds of tube substitutions we used to get away with back in the day. This is a slightly different beast. Tube substitutions,... please don't do that. 1 Quote Link to comment Share on other sites More sharing options...
charlesdavid75 Posted March 1, 2017 Share Posted March 1, 2017 Mesa, Groove Tube, JJ's,... fine tubes. Just not in a Bogner designed amp. These are hybrid amps with both analog/digital with tube and solid state components. These are not the tube amp of the 1960's yester-years where you can swap tubes willy-nilly and have it work. These amps are very particular. Stick with the specified tubes. Those are the Sovtek 5881WXT Matched Pairs with the cup based bottom, Chinese 12AX7B is good. They are not designed to handle substitutes. I see too many come across my bench with substitutes, and incorrectly biased power stages,... so they come to me blown and not working because of it. You can't get away with the same kinds of tube substitutions we used to get away with back in the day. This is a slightly different beast. Tube substitutions,... please don't do that. Quote Link to comment Share on other sites More sharing options...
charlesdavid75 Posted March 1, 2017 Share Posted March 1, 2017 I have read and completely understand, a lot of engineering went into what makes the Bogner/Line 6 amp. I respect it's differences and what makes it unique. With that said I intend to keep it stock so it can run long and strong. I have a matched quartet of Sovtek 6L6/5881WXT tubes and a pair of 12AX7B China tubes on the way. My question, what is the specified bias value for the Line 6 Spider Valve MKII power tubes? Quote Link to comment Share on other sites More sharing options...
psarkissian Posted March 1, 2017 Share Posted March 1, 2017 For Spider Valve, with 5881WXT,... +35mV(dc) +/- 2mV. It's in the Knowledge Base somewhere. Quote Link to comment Share on other sites More sharing options...
charlesdavid75 Posted March 1, 2017 Share Posted March 1, 2017 Thank you so much. Many thanks. I'm really glad you have warnings of possible issues noted on the forum. I'm rather new to tube amps and bought the Spider Valve MKII used and it sounded fantastic, but now it's not as it once was. I'd just like the best possible tone like everyone. I truly believe it's possible with this amp, though it may take many hours of fine tuning. Quote Link to comment Share on other sites More sharing options...
greenjupiter Posted September 9, 2018 Share Posted September 9, 2018 Watsup people! new to the forum and line 6.just picked up a used (but never really used) spider valve 112 mkii. the guy who sold it to me barely ever used it and never changed the tubes since he bought it in 2015. seems to work fine for now but first question... Should i change the tubes now before i really start playing with this amp? is there a way to tell if the tubes are still good? also just want to make sure these are the correct tubes for this amp. https://www.long-mcquade.com/46848/Guitars/Parts/Sovtek/Pair_Of_Matched_5881WXT_Tubes.htm and https://www.long-mcquade.com/13150/Guitars/Parts/Sovtek/12AX7_-_9_Pin_Preamp_Tube.htm and lastly do i need to bias my amp when i change the tubes? Thanks guys! Quote Link to comment Share on other sites More sharing options...
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