#1
Soo about 3 months ago i got a new set of tubes(pre amp and power). had it biased quite hot, around the 35-40 mark. I play on average of about once a day for 1 hr. Ill usually play with the volume as loud as the crappy behringer cab can handle before its speakers sound like there going to die. I play with the gain quite high (metalcore) boosted with a tube screamer. During the 3 month life of these tubes, the amp has been shut straight off (without going to standby to let them cool down) 3 times. Accidents of course.
Last week at band prac i accidently kicked my mains power out during a song, i plugged it back up and it just sounded differant, sounded like there was a bit of a crackle that was'nt there before. i thought i had blown a speaker(s) in the cab because the amp was really loud, but i tryed it with another cab and it did the same crackle when i palm muted and the bass gets heavy. Soo anyone have any thoughts on what this might be, if its a tube or somthing more serious. thanks

AMP: FRAMUS COBRA
TUBES: 4x SOVTEK 6550@40MA, 2x TUNGSOL 12AX7, 3xSOVTEK 12AX7
#2
That sounds like a power transformer or power tube issue.
You can get a new set of power tubes and try it yourself, but know that you might need to take it to a tech after that to have the transformers and power supply checked out.
#3
Quote by donni69
Soo about 3 months ago i got a new set of tubes(pre amp and power). had it biased quite hot, around the 35-40 mark. I play on average of about once a day for 1 hr. Ill usually play with the volume as loud as the crappy behringer cab can handle before its speakers sound like there going to die. I play with the gain quite high (metalcore) boosted with a tube screamer. During the 3 month life of these tubes, the amp has been shut straight off (without going to standby to let them cool down) 3 times. Accidents of course.
Last week at band prac i accidently kicked my mains power out during a song, i plugged it back up and it just sounded differant, sounded like there was a bit of a crackle that was'nt there before. i thought i had blown a speaker(s) in the cab because the amp was really loud, but i tryed it with another cab and it did the same crackle when i palm muted and the bass gets heavy. Soo anyone have any thoughts on what this might be, if its a tube or somthing more serious. thanks

AMP: FRAMUS COBRA
TUBES: 4x SOVTEK 6550@40MA, 2x TUNGSOL 12AX7, 3xSOVTEK 12AX7



you don't actually have to put it on standby before turning it off dude. you can just shut it straight off (turning it on is a different matter) i honestly have no idea what that could be though most likely a tube issue though just because it only started after the power got kicked out.
#4
Quote by Lt. Shinysides
you don't actually have to put it on standby before turning it off dude. you can just shut it straight off (turning it on is a different matter) i honestly have no idea what that could be though most likely a tube issue though just because it only started after the power got kicked out.


+1.Standy just heats up the tubes without letting any signal through.Signal going across cold tubes=not good.Putting them on standby just leaves them cooking.
But leaving the tubes to cool down before you move amp is a good idea I hear.
Seagulls,the chicken of the ocean.

Originally posted by Gunpowder:
Everyone just jumps on the bandwagon and gives the same advice in these situations. You know what? I'm going to be different. Call the firemen.
#5
Quote by Ian hawkins
But leaving the tubes to cool down before you move amp is a good idea I hear.


Putting your amp to standby doesn't cool it down.

When in standby, current is running through the plate of the tubes. Even if you switch the amp to standby before turning it off, current is still running through the plate, heating up the tube.

Hence it does nothing.
Quote by Blompcube
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#6
The aptly named heaters, not the plate, receive current when the amp is in standby.
#7
I agree with Roc. also, framus cobra... might be wise to invest in a roadcase for your head to give it a little safety net from shit like that.

oh, and Lt.SS's right, you don't NEED to go to standby before turning your amp off, but you'd be wise to do so just to let it discharge.
#8
Quote by Roc8995
The aptly named heaters, not the plate, receive current when the amp is in standby.


Mah bad... haven't research much into the inards of tubes yet.
Quote by Blompcube
it's so cool to hate Gibson, even the federal Department of Justice hates them.

( )( )
( . .) This is Bunny. Copy and paste Bunny into your
C('')('') signature to help him gain world domination.
#9
Quote by Ian hawkins

But leaving the tubes to cool down before you move amp is a good idea I hear.


This is true for all electronic equipment. The theory goes that if a device is hot enough the solder may have started to melt and any jolts at this time could dislodge a component or leave you with a dodgy joint and intermittent problems.

It is good however to leave the amp on standby for a few seconds after you finish playing just so any current still working its way round the amp is discharged into the earth rather than being dumped into the amp which results in a big pop if you are really unlucky.
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