Mark IV Power Tubes Running Blue?

[ibanez4life SZ!]

Hey guys!

I brought my Mark home to do some more tweaking today, and taking a look at the back, noticed that my powertubes, when unstandbying the amp, glow blue, close to the base...it's basically a blue ring around the tube about where the 440 on the tube is marked...

I am currently running the amp in Tweed btw.....

Is this bad? I noticed it goes away immediately when I but the amp back into standby....

It has me a bit worried, as I've been playing the amp for a week or two now, and only just noticed this....

Is something wrong?

 

[disassembled]

No actually this is absolutely normal. You will notice that with Sovtek/EH tubes (AKA STR 430's/425's) that you will get a lot of blue glow when the amp is operational.

The 440's are Chinese tubes and I think they have a nice glow to them as well depending up how much current they draw (the more current usually the brighter the glow).

JJ's, on the other hand, are not as apparent in operational mode so you have to look inside the plate for a blue glow. What you want to look out for is 1 tube that is REALLY blue and the others look the same or if the gray plates in the middle of the tubes turn red and stay red.

I can't confirm this info but on a couple of boards people would say that tubes with a bad vaccuum will glow more(due to the electrons having more movement or something I believe). I don't know how true this is because every EH/Sovtek 6L6 tube i've seen had the same blue glow that was more like a cloudy haze inside the tube. Visually, I find it pleasing and think it looks neat but I can't tell you if it's good for getting the best tone or not.

If you have 430's in your Dual Rec you should definitely fire them up in the dark and you will see a nice blue haze in all 4 of the power tubes.

Greg

 

[MusicManJP6]

What he said. Haha. Good explanation!

Your new baby is working perfectly!

 

[70sRock]

ibanez4life SZ!
I have been following your progress with your Mark IV. I also have just received my Mark about three weeks ago and I was wondering if you have noticed that the Mark has a lot of noise/hum with the guitar plugged in and while idle, not playing.

I have the amp set to the demo settings listed on page 2 of the manual and the hum and hiss/buzzing are quite noticable in all channels. This would cause a problem live and even more when running the amp through a PA.

I have tried several guitars and cords. Have tried moving it to different rooms to get different main power, the amp seems to be senative to the main power from the wall also. The amp is dead quite if powered on with no guitar plugged in or if the guitar volume is turned down. I also unplugged the fan to see if this was the cause but the noise was still there.

I have looked at the tubes and they look the same as yours.

I was wondereing if this is normal for this amp and if this is why people use noise gates.

Thanks for your help.

 

[fpoon]

70sRock: If you turn the Gain at 8 or past it I can understand that your are getting some hissing. Lot's of Mark IV owners say that the amp is really quiet by I also got some feedback and humming like you. You may be connected too close to other electrical appliances such as T.V's etc. Another problem could be from the wiring in your house or a bad outlet (I had this problem and had to get a noisegate, the feedback was unbearable!). Also, check to see if the grounding in your guitar is good.

I just read that your amp is dead quiet when your guitar is unplugged or when the volume is turned down. I think mine was still humming with my volume down so you may have a bad preamp tube or just be expierencing microphonics.

 

[MusicManJP6]

My Mark IV A was noisy in the Lead channel with the volume down on the guitar and unplugged, but it sounds like yours is guitar related, 70sRock. You might have some hot pickups, or microphonic pickups, or a bad ground. Try another guitar and see how noisy it is then...

 

[Shep]

my mk IV A is really quite.. even with everything Dimed.. might be a noisy Tube?

 

[Russ]

my mk IV A is really quite.. even with everything Dimed.. might be a noisy Tube?

+1, or a bad cable or guitar electronics.

 

[70sRock]

Great input, thanks for your help.

I have tried most of these; different guitars (PRS and a LP, both are stock and have the same noise problem), moving the amp to another room, different cords, standing at different positions around the amp, etc.

I understand that these would have a slight hiss or noise because of the high gain but this is a hum with a buzzing and is very noticable when standing away from the amp in a small room.

I still need to try different/moving the preamp tubes and checking the grounds.

One question, if it is my house wiring that is causing the amp to be noisy would a noise gate help? Is this what noise gates are used for?

Thanks again for your help, these have given me some other ideas for things to try.

 

[MusicManJP6]

I think my noisy amps are because of the crappy wiring in the apartment complex. I just got my Roadster head and it is noisy like my Mark IV was. It must be the wiring, or the pups in my JP guitars...

 

[fpoon]

One question, if it is my house wiring that is causing the amp to be noisy would a noise gate help? Is this what noise gates are used for?

Yeah, it will elimate most if not all your humming and feedback, thats exactly why I got one. I bought the MXR SmartGate and now whenever I stop playing the amp seems like it's off.