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I have a Line 6, Bogner, Spider Valve HD100 and I'm replacing the tubes on it. I need advice on biasing the amp after replacing the tubes. I didn't see anything in the manual about what to set the bias to. Does anyone know?

I have this amazing amp with a user friendly interface, but after warming up, about 30 min to an hour, the power turns off and on by itself. Does this sound like a tube problem, a power supply problem or what? I love this amp but I can’t depend on it! Help!

Hey everyone. So this is my first tube amp, and it was working great so far. However, Yesterday during band practise, after it had been on and working perfectly for two hours, the volume suddenly dropped. When I checked the amp to see what was going on, I noticed that one of the tubes (the one on the left) was way hotter than the others. when I turned down the volume, where was a small lightning inside the tube, and then no sound. From what I've gathered from the internet, the tubes weren't paired or biased properly. When the amp is on, the other tubes light up normally. Anyway, when I bought the amp, the people at the store had only two tubes installed (the two in the center), to cut the output down and make it playable in the store. I wanted to know if there is any specific manipulation to do in order to do that. (I have a gig in 4 days and I probably won't have neither time nor money enough to have the tubes changed and the amp biased before then).

Problem: While playing recently, my DT-25 suddenly dropped volume significantly and had a slight burning smell. I figured it was a tube(s) going out, so I bought some new ones and replaced them, but when I went to bias them, they were super low! Instead of the 25 (+/-3), they were around 7-8. I turned the bias, but then the weirdest thing happened - any turn up would start an unstoppable climb to 40-50, then it would suddenly kick down to 14 or less. It would stay that way until I turned the bias up again, and then the same thing every time. I checked the fuse, but it seems intact. Since power was going to the tubes, I figure it can't be that anyway. I may be wrong, but I suspected it may be kicking into Low-Volume mode as a safety feature. Any idea what's going on? How do I fix this?

Hey gear heads, I am wondering if i can use 12au7 and 12ay7 pre-amp tubes with my Bogner Alchemist Head? I guess the real question is what other tube options do i have other than 12ax7/ecc83 and 6l6/5881 Much Appreciated.

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.

First of all... It's been ages! Feels like I went away a thousand years. I can't believe there was a time when I was one of the most regular regulars around here :o My question: well, the topic title says it all. It's the time to change the factory tubes of my Spider Valve 112 and I want to know if it's safe to replace the original Sovtek 5881 power tubes with Sovtek 6L6WXT+. I don't mind if the tone changes a little as long is not for the worse. Thanks for your attention.

Here's what I propose; An app that would allow us to "design" our own tube amps that we can upload onto the Helix and share with other Helix users. The amp would allow us to mix and match all components of an amp and its design paradigms (Fender, Marshall, Boogie, etc.) and swap out tubes, caps, resistors, pot values, negative feedback amount and "power supply" robustness (sag/tightness). Mix and match manufacturer designs between preamp and power amp. All without the danger of electrocution and being able to ignore most the laws of physics and electricity. I'm thinking of this as something along the lines of the Variax Workbench. You don't have to understand electronics and tube design, just be willing to experiment. I'd be willing to buy this app. It doesn't need to be free. Please upvote it. http://line6.ideascale.com/a/dtd/Amp-Developer-App/841518-23508

Hi guys. How difficult is it to do this?. I just bought one of these units and I live in a country where there is no one that provides this kind of service. Shipping the head to the US for service would be extremely expensive both ways. I'm thinking that I should have bought something else. Your comments would be most welcomed JG

Nice to have a chance to say something good. I got a used DT25 that looked like new. Seller disclosed that is had a little humm to it. Before I got it I researched this forum and felt strongly that it was a tube problem, so I took the gamble and got it at a very good discount. I have a HD500X that I was looking to get a close proximity to the tones I was hearing with my headphones and monitor speakers. When I got it home I really was disappointed with the sound even overlooking the hum. The tones were harsh and not really pleasurable to play. But hey, I had purchased replacement JJ's for all 3 tubes. I took it to my amp guy and he frowned when he heard to strong buzz and hum. He said it might be the under sized Caps or something else. Then I frowned. He called today and said he changed to tubes and biased to 0 distortion. (not really sure what that means) and he said that was all it was, and... it sounded great! Whoo Hoo. I ran down to his place and plugged it in at the shop and cranked it. Strings muted, it was as quiet as a church. Sound was clean on clean, crunchy on crunch and sustain was twice as much as before. Got it home and played and played. HD500x sounds clean and correct with just changing presets to Amp PRE's. Is it the JJ's? or maybe it just sounded so bad with the fried Power Tube, I don't know, but I am really impressed with the sounds this thing can produce at live levels. All good for today! Rock On.