psarkissian

Use the recommended cable and cable length. Line 6 link cable and mic cable are not the same. Impedance are different and the uses are different. AES/EBU,... it's the standard issue for this sort of application. For the uninitiated,... AES being the Audio Engineering Society, and EBU as in the European Broadcast Union.

The Sovtek 5881WXT is what Rheinhold Bogner spec'd for this one (Spider Valve series). The Sovtek 5881/6L6 WGC doesn't have the cup at the bottom which created problems with tube retainers so we don't use those anymore. People want the crunch of a Mesa tube, unfortunately too many with Mesa tubes come back with problems. JJ's and GT's also come back to us with problems, and things like the bias being way off-spec. The Sovtek 5881WXT is what Rheinhold Bogner spec'd for this one (Spider Valve series). There are interactions between the digital portion and the tube portion, such that, it is not as forgiving as old 60's as 70's tube amps. You can't get away with the same deviations with these as we used to with older tube amps. We have our tubes go through some extra scrutiny. Best to stick with the specified tubes,... less problems that way.

No, I'm not new,... the thread is out-of-date. I'll let Dave know, thanks. I've been dealing with Spider Valve since the beginning, been dealing with tubes and tube amps for more than four decades. The characteristics curves of the JJ's, Mesa's and Groove Tubes are not close enough. If those are biased the same to the bias settings for the 5881WXT's,... then the amp ends up on my bench with problems. Can't use the same bias settings on these other tubes as with the 5881WXT. I see too many come back because of the wrong tube and/or bias settings. This is a mixed technology amp. You can't get away with the same sort of things we used to get away with for Marshall amps with 6550's in them. These amps are not as forgiving as the tube amps of yesterday-years. It's a Bogner hot-rod.

Be sure to use the correct impedance output for the cabinet that you are using. They have to be matched or the tubes and circuitry will get stressed,... and then it will end up on a technician's bench. And that's no fun. Keep your fingers out of the inside of the amp,... even with the power off, a capacitor can discharge into your hand, and that hurts like hell.

And use the specified Sovtek 5881WXT, matched quartet tubes. No JJ's, Mesa's or Groove Tubes,.... if they are biased the same as the 5881WXT, there will be problems, the characteristic curves are not matched close enough for use in this amp.

"I was just wondering if the "two tubes out" solution would work as a temporary solution in case I could not get it done before the upcoming gig." ---- No! Don't do that. These aren't our grandfather's tube amps, these are mixed technology amps, you can't get away with this sort of thing like we used to in the old days. They are not designed to do that.

It may be only that it's time for a tube change out and bias. Good idea to do that once every 12-18 months if you're a performing musician. Have it checked out at a Line 6 authorized service center in your area, that knows tube amps. Sales person should have never pulled two tubes out of it,... much less the wrong two tubes. It offset the push-pull symmetry. That and how long they've been in the amp is probably why the one tube was hot. Don't try to deal with it yourself, it hurts when you get zapped. Take it in to a service center, have the right tubes put in and biased by a tech.

Tube amps should be dealt with by a Line 6 authorized service center. They will have access to service manual and service info. There's more to the bias procedure than adjusting a trim pot. Specified tubes should be used. I see too many amps come across my bench because someone tried to hot-rod an amp that's already hot-rod. It's a hybrid amp with a digital section and with multiple gain loops and amp classes. Using non-spec tubes will create problems. Using incorrect bias will create problems, bias is not a "one size fits all" proposition. These aren't our grandfather's Marshall or Phase Linear tube amps. Leave it to the guys with the service info access. Besides,... it really hurts when you touch the wrong thing and get zapped!

Workbench is the way to make such adjustments,.... The piezo sensitivity is what it is, and there's nothing on the circuit board for physically changing that.

Don't do that,... It's a keyed connector, you'll break it. If you pull the pins out of the connector and and a pin breaks you'll have problems maintaining a connection.

No "innovine", got it wrong. Not trying to drum up business, trying to keep your gear from ending up on my bench. Sorry if you think otherwise.

That and other things. As for what's on the board,... can't get into that. Klystron is a special kind of tube used for power amp outputs at hi wattage commercial radio stations. Also used in microwave communications. Oh, and,... in certain situations the oil can are used as coolant for the tube.

Just don't stand in front of the waveguide when it's powered up. Hope the tube you're using is a klyston.

For guitar amps, Bogner knows how to deal with it, he's good at it. Audiophile tube amps are another beast and specially all their own. And there are techs like me who deal with both,... and radio station transmitters as well.

If you were to take transparencies of the characteristic curves of the the different brands of EL34's and EL84's, and overlay them, the linear regions of the transfer may line up, but it's the where and how non-linear regions of the curves differ that will create the problems. I've built my share of tube amps, I've been servicing tube amps for decades. No voodoo, no lollipop,... it's just plain physics of electronics.

innonovine: "JJ's have a tendency to damage certain parts of the processor board--- Which parts, exactly, and why? Citations needed"--- Unless you're an authorized service tech and signed an NDA (non-disclosure form),... I can't get into that any deeper than I already have. Sorry. Don't use JJ's, use the specified EH's,... the JJ's will go outside the linear region of the characteristic curve too easily, and that will create problems further downstream, and stress the circuits. And I would have to have give an online course on tube amps for the uninitiated. Right, there is no voodoo,... just knowing what the technology is and where the limits are. Don't go beyond the limits,... physics is unforgiving in that way.

1. Good. 2. Low risk. 3. Volume cut-outs, crackling noises,.. stuff like that. Just play the amp, don't mod it or do anything strange to hot rod the hot rod.

"I smell a BOM (Bill of Material) component value stuffing error during PCB assembly"--- Doubt it,... more like diffuse light wave, wave guide, or debris in the way.

Charlie on the spot. Correct. ColonelForbin,.. the Shuriken guitars would have to do it the way Charlie says it. I know, I've done it. As for 59 vs 69, the board is the same, It's the program that's different. No "Zap",... the controls stay the same.

radatats is right,... "... while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode"---- The power tubes that come stock with these are "pentodes", that's how the circuitry is designed. Don't mod these amps, use the specified tubes, you will have less problems.

Melted glass is usually a result of 'red plating'. It can get so hot, that the glass will melt and pucker until it cracks and loses vacuum. Seen that more times than I would like to. Depending on how much gigging you do, tubes ought to be changed out every 12-18 months. If you're a recreational player and don't gig or record much, you can get away with 2 to 2-1/2 years. But, yes,... I've seen tubes in amps in general (at other places I've worked) last two weeks in one amp and 5-years in another. Partly the amp, partly the tube. "What precautions can we take to ensure that our amps don't wind up on your bench?"--- Don't try to modify it, use specified tubes, change out tubes on a regular basis. It's your friend, your tools, take care of your tools. And used Line 6 authorized service centers, as they will have access to proper service info,... at least while your warranty is good. And by all means,.... please DON"T go inside these amps yourself, the shock hazard is too great. Don't want read about how someone got zapped messing with a tube amp. This is dangerous,... I'm a tube geek, I was trained to do this, been dealing with tube amps and solid state amps since the 1970's. And been zapped enough to know better.

Yes. Red plating isn't the only way to damage the unit. To explain that further gets into aspects of the circuit that I can't get into. It all goes to the characteristic curves of the tubes. JJ's have a tendency to damage certain parts of the processor board, Mesa's tend to "red plate", and Groove tubes tend to do a host of other things. Part of it is that it's a Bogner hot rod, part of it is that there are multiple gain topologies that are on this amp that can be engaged, and so messing with it is not a good thing to do.

There's a bias voltage specified by Bogner and our engineering dept. Can't get into Plate voltage on a DT-50,... sorry. It's a lot, so don't mess with it. It hurts when you get zapped.

-Red Plating, for one. Too much current going through the plate element. -Biasing other brand tubes to the same spec as the EH's would not be a good idea. -Circuit is designed to operate in the linear region of the "characteristic curves" of the tube. Other brand's linear regions don't always match curve-to-curve. If you go non-linear too soon, distortions and other related problems occur,... stuff starts to get damaged or blown. Bias and gain stages play into this. -And with a hybrid amp like this, one of the things that typically goes, are a couple components on the processor board. -There are multiple gain structures on the amp board, using tubes with afore mentioned aspects also play a part in what can get damaged. Other aspects I won't go into because it's a tube engineering thing that most people won't get (except tube geeks like me),... and because there are also aspects I can't get into because it's proprietary. Pushing a hot rod to the edge is not a good idea here. It's already a hot rod, and a hybrid one at that.

"It was like a crackle pop sound"--- electronic,... a few different possibilities. An authorized service center could narrow it down, nip it in the bud, and check the set-up,... all at once. JTV's are all set-up and checked out before they leave the distribution center. Cross country travel, climate change from region-to-region can have an affect on the set-up. The set-up may need to be dialed-in a smidgeon.