1.21 Gigawatts

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1.21 Gigawatts

Post by RectifiedAmps »

Ok, here's something crazy... a Jansen Bassman came in for repair after going up in smoke during a gig. I'm no rocket surgeon, but it looks like arcing between the anode and filament pins on one of the power tube sockets. Crazy thing is - this is a CERAMIC socket... I've never seen ceramic melt/burn like this before! Jansens have almost 600V on the plates, so there's a lot of electrical potential and there must've been a huge amount of current flowing to rip through the socket like this. All that current flowing through the output transformer fried it plus it took out the power transformer as well. Mains fuse didn't even pop - surprising, but it goes to show that they're really only there for safety, not to protect your amp from damage. No other fusing is present in this design, although this is a good example of why it's always a good idea :(
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Re: 1.21 Gigawatts

Post by telefiend »

Sheesh!

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Re: 1.21 Gigawatts

Post by calling card »

looks like it would have been arcing there for a time then the final fusion.
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Re: 1.21 Gigawatts

Post by olegmcnoleg »

From wikipedia . "Ceramics generally can withstand very high temperatures, such as temperatures that range from 1,000 °C to 1,600 °C (1,800 °F to 3,000 °F)."


That's quite frightening.

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Re: 1.21 Gigawatts

Post by sizzlingbadger »

Electrical arcs produce crazy high temperatures up to 20,000 °C , hence their use as cutting tools.
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Re: 1.21 Gigawatts

Post by Kris »

pretty sure i saw pics of that going up in smoke on face book,and the fact that the band kept playing as it was smoking away.... :rofl:

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Re: 1.21 Gigawatts

Post by RectifiedAmps »

Kris wrote:pretty sure i saw pics of that going up in smoke on face book,and the fact that the band kept playing as it was smoking away.... :rofl:
What you can't see in the vids is that apparently the walls were dripping with humidity. Just a guess but I bet all the moisture in the air was a contributing factor to getting the arcing started.

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Re: 1.21 Gigawatts

Post by tubeswell »

600V is too much for ordinary 6L6s (including 6L6GC in that category). To easy to get inter-electrode/pin arcing between Pin 3 (plate) and Pin 2 (heater)
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