Power tube failure now no sound

Get support and show off your MetroAmp JTM 45 kit builds.

Moderator: VelvetGeorge

Post Reply
User avatar
astral
New Member
Posts: 28
Joined: Wed Jul 25, 2007 10:34 am

Power tube failure now no sound

Post by astral » Tue Jan 11, 2011 6:54 pm

Playing my JTM45 and the sound faded out like I just switched it off.

Checked the tubes and one of the KT66s was not glowing, powered off the amp and pulled the tubes.

It appears the vacuum had failed on one of the power tubes. Original valve arts that came with the kit.

Popped in a couple of new Sovtek 6L6WXT I had and powered back on.

Everything lights up fine but no sound

Before I start pulling things apart what are the like culprits component wise ?

What’s the chances on losing th OT with a power tube failure :?:

Cheers

bg

User avatar
mathd
Senior Member
Posts: 219
Joined: Wed Jan 30, 2008 10:57 pm

Re: Power tube failure now no sound

Post by mathd » Tue Jan 11, 2011 8:00 pm

If it just fade out and no smoke i wouldnt worrie too much.
Did you replace the fuse? Also bias the new tubes.
If that check fine and there is still no sound, i would check voltage from the build instruction.
Mathieu

User avatar
Mars Hall
Senior Member
Posts: 955
Joined: Mon Dec 17, 2007 9:49 pm
Just the numbers in order: 7
Location: The Region, NW Indiana

Re: Power tube failure now no sound

Post by Mars Hall » Wed Jan 12, 2011 6:56 am

More specifically the HT fuse. The light and heater filaments will still glow when the HT fuse is blown. The fuse may "look good" but replace it anyway.
"You just slide a bottle up and down til what you want out of it comes out. You just slide away at it til you've got it down." Duane Allman

User avatar
astral
New Member
Posts: 28
Joined: Wed Jul 25, 2007 10:34 am

Re: Power tube failure now no sound

Post by astral » Sun Jan 16, 2011 6:59 pm

Cheers,

Good call on the fuse.

Its a relief to have those speakers shifting air again.

bg

Post Reply