Blown output tranny?

[drewl]

Whaddya' think....?
Boutique expensive amp with cracked broken tube socket.
Replaced socket, powers up fine until output tubes are installed then blows fuse a couple seconds after power up, probably milliseconds..
Tried different output tubes, tried different rectifier, yes socket is wired correctly, it uses pins 1 & 6 as tie ins so I made sure to try output tubes that don't have 1 or 6....same thing.

i'd be bummed if it was my amp.

[HTH]

do you have a suitable OT handy that you could temporarily hook up to the amp?

[dwhutchens]

Could it be missing output tube bias?

[Enzo]

Amen, what are the voltages around the sockets?

If the OT primary is shorted to frame or to secondary, it will pop fuses without tubes. If the primary has shorted turns, i don;t expect it to pop fuses instantly. it might not bias up right or it might run finny, but I still don;t expect tubes to matter.

Turn off the room lights and watch the sockets for little blue arc fire.

How about this: does it blow fuses with tubes in but leaving the standby off? Or does the standby have to be on also?

And it wouldn;t hurt our feeliongs to know what amp this is. SOme have B+ on the tube plates all the time, while others turn it off with standby

[R.G.]

Whaddya' think....?
Boutique expensive amp with cracked broken tube socket.
Replaced socket, powers up fine until output tubes are installed then blows fuse a couple seconds after power up, probably milliseconds..
Tried different output tubes, tried different rectifier, yes socket is wired correctly, it uses pins 1 & 6 as tie ins so I made sure to try output tubes that don't have 1 or 6....same thing.

i'd be bummed if it was my amp.

Tube Amp Debug Page, Geofex.

[drewl]

Okay, this is a good idiot error.
It seems someone kept jamming the tubes in wrong so there was a slot in the socket that I didn't change so everytime I popped a tube in, it went in wrong. I had to look and line up the slot properly.

No wonder they broke/cracked the other socket.