Bad tube?

[DirtySteve]

My amp is starting to sound fizzy, the low notes are getting plinky and buzzy sounding and over all the amp is starting to sound weak. It has 2 6v6 power tubes, one is glowing and the other is barely glowing. Is this a sign one of them is going bad? I have some spare preamp tubes (if I can locate them) and I can roll those to check the pres but they all glow normally. I don't have any spare 6v6s so I wanted to ask if this sounds like a power tube before I get into this.

What should be my troubleshooting process here?

 

[DirtySteve]

I'm not even sure all my pickup swapping in my new LP was legit because I think this problem may have started during the process without me realizing it.

 

[bea]

Unfortunately not too specific information ... but a probabilistic argument: preamp tube tend to last "forever" - power tubes need to be changed more often. In Your case i would by a new pair of 6V6 and keep the old ones as backups.

BTW are there visible sign of tube aging in the glass?

 

[67plexi]

Change your phase inverter 12AX7 also when replacing power tubes the JJ-6V6-S have held up well for a new production
they can take 450 VDC good luck.

 

[Cadorman]

I had a minute crack in the glass of an EL34 and it blew the fuse every time I took it off standby. Get new power tubes and have spares available.

 

[Jethro Rocker]

Yeah sounds like it to me too. Weak sound usually means weak tubes.

 

[DirtySteve]

Unfortunately not too specific information ... but a probabilistic argument: preamp tube tend to last "forever" - power tubes need to be changed more often. In Your case i would by a new pair of 6V6 and keep the old ones as backups.

BTW are there visible sign of tube aging in the glass?

No sign of aging, no. They both look new actually.

 

[Boo]

They totally suck. I'll sell you new ones.

 

[DirtySteve]

I just turned the amp on and this time I turned out the lights and can now see that one of the 6v6s is blowing blue. I couldn't see it until I shut off the lights.

 

[DirtySteve]

Change your phase inverter 12AX7 also when replacing power tubes the JJ-6V6-S have held up well for a new production
they can take 450 VDC good luck.

Really?

 

[Thatbastarddon]

Really?

Yep.

 

[Boo]

Do it.

 

[DirtySteve]

The reason I ask is I have some really nice NOS pres that were gifted to me when I built the amp. I'd hate to pull any of them if they aren't bad.

 

[ivan H]

I just turned the amp on and this time I turned out the lights and can now see that one of the 6v6s is blowing blue. I couldn't see it until I shut off the lights.

This type of blue (or sometimes violet) glow, most often seen in power tubes
is no problem. It is a result of elctront bombardment of the glass inside the tube.
I agree with @67plexi, change out the phase inverter tube when you renew power tubes (it gets worked pretty hard).
More info needed on your problem, a great number of things could be causing it. What type amp are we talking about. Cheers

 

[Jethro Rocker]

They totally suck. I'll sell you new ones.

Hey you are back. Living at Dad's again?

 

[Boo]

Hey you are back. Living at Dad's again?

I'm moving up north with dad in the morning JR.

 

[syscokid]

... when I built the amp.

Aha... the plot thickens... What amp did you build here? Is it used a lot?

If your amp's problems are tube related, it's always good to have spares anyways. There are plenty of trusted online tube vendors that will guarantee you a matched pair of quality power tubes.

 

[Inspector #20]

My amp is starting to sound fizzy, the low notes are getting plinky and buzzy sounding and over all the amp is starting to sound weak. It has 2 6v6 power tubes, one is glowing and the other is barely glowing. Is this a sign one of them is going bad? I have some spare preamp tubes (if I can locate them) and I can roll those to check the pres but they all glow normally. I don't have any spare 6v6s so I wanted to ask if this sounds like a power tube before I get into this.

What should be my troubleshooting process here?

#1 - Guitar Cable Swap - I have recently had the exact issue you are describing from a brand new - but faulty - Guitar Cable.

 

[DirtySteve]

I was hoping this would just go away.

...it was user error.

 

[Inspector #20]

My amp is starting to sound fizzy, the low notes are getting plinky and buzzy sounding and over all the amp is starting to sound weak. It has 2 6v6 power tubes, one is glowing and the other is barely glowing. Is this a sign one of them is going bad? I have some spare preamp tubes (if I can locate them) and I can roll those to check the pres but they all glow normally. I don't have any spare 6v6s so I wanted to ask if this sounds like a power tube before I get into this.

What should be my troubleshooting process here?

#1 - Guitar Cable Swap

I was hoping this would just go away.

...it was user error.

Cheapest problem to have