Voltage Rating(DC) of 9-pin tube socket

[67plexi]

I have one of the first Seymour Duncan 84-50 it was real hard on EL-84's
one day it took out the secondary PT B+ winding Sorry I never did a voltage
chart on the amp. My latest fun is with a cruse ship line 400 dead Mesa Lone star amps I have only repaired one so far but the 5y3 EL-84 quad and PI were all fried or shorted I suspect dirty generator power or massive spikes was the cause. The funny part of the story is the customs and TSA
stickers all over the amps they just sent two more I have to pick up.
Charlie if you can find the Russian 6N14N-EP 7189 EL-84 they worked the best in the SD 84-50 amps.

Steve.

[Leo_Gnardo]

400 dead Mesa Lone star amps I have only repaired one so far but the 5y3 EL-84 quad and PI were all fried or shorted I suspect dirty generator power or massive spikes was the cause.

I thought Mesas were supposed to have those MOV's in 'em to make 'em bulletproof, they used to run ads based on that: "we're tougher than the rest." But multiple spike hits to those MOV's will eventually kill 'em. I wonder why the Lone Stars went legs up while other gear apparently survived just fine. Maybe the line voltage is just a little too high, say 135 VAC, not enough to enact MOV protection but certainly enough to make the tubes unhappy. Cruise line better order up a bunch of line conditioners from TrippLite or similar. 400 of them you say, wow that's a project!

[Charlie Wilson]

I have one of the first Seymour Duncan 84-50 it was real hard on EL-84's
one day it took out the secondary PT B+ winding Sorry I never did a voltage
chart on the amp. My latest fun is with a cruse ship line 400 dead Mesa Lone star amps I have only repaired one so far but the 5y3 EL-84 quad and PI were all fried or shorted I suspect dirty generator power or massive spikes was the cause. The funny part of the story is the customs and TSA
stickers all over the amps they just sent two more I have to pick up.
Charlie if you can find the Russian 6N14N-EP 7189 EL-84 they worked the best in the SD 84-50 amps.

Steve.

Thanks Steve. There are several other amps that are hard on EL84s that I have repaired in the past so maybe finding some of those tubes would be a nice upgrade to offer a customer with a EL84 torturing amplifier.
CW

[guitarmike2107]

As RG pointed out pollution inside the amp is a big problem, so keep it clean/serviced.

Also make sure the spacing between the pins is even, and I personally would insulate the plate and screen pins with heat shrink, so that you cover as much of the exposed terminal as possible, even a non conducting varnish/nail polish coating would help.

[67plexi]

Charlie, This is what I'm using for 7189 it can take 450v all day long.
https://www.tubedepot.com/products/sovt ... acuum-tube
This is a photo of #2 Mesa 5 fried resistors one bad EL-84 did this