Chinese 811A tubes

[N2RJ]

High failure rate is all I have to say about these.

Bought a new set from Ameritron, one of them was shaking (broken filament) right out of the box. Needless to say it's going back.

The previous set lasted less than a year, before it developed a grid to filament short, taking out a grid resistor and fuse in the process.

I think next set of tubes I might buy svetlana or look for NOS taylor or RCA or something better.

Chinese tubes vacuum hands down.

[N9FE]

Yes.. Replace with 572b's Ryan.. Ameritron does not have a problem with the swap... Way tougher tube.. But if you want to stay with 811's nebraska sales has them cheap.. cetrons too

[N2RJ]

I had actually replaced them with 572b earlier on when I first bought the amp but one of them broke off the anode cap and the rest of them just slowly began to melt their cold soldered anode cap joints.

I may fix the anode caps in the old set of 572b and put them back in the amp...

But at this point I'm just not happy with the chinese tubes.

[w2amr]

High failure rate is all I have to say about these.

Bought a new set from Ameritron, one of them was shaking (broken filament) right out of the box. Needless to say it's going back.

The previous set lasted less than a year, before it developed a grid to filament short, taking out a grid resistor and fuse in the process.

I think next set of tubes I might buy svetlana or look for NOS taylor or RCA or something better.

Chinese tubes vacuum hands down.
I replaced the 811 modulators in my Johnson 500 transmitter with JANs, that was over 10 years ago. They are still going strong.