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tennessee walker

I recently got a Tennessee walker with 2 250b inside and the guy I got it from was putting 250 into in on hi drive and getting 1500 average out.

I am new to tube amps and am wondering if that’s ok to do and what can you put into it on low drive?

thanks!
That doesn't seem right at all. Even if the amplifier is cathode driven, it's way too much drive and the wrong way to use this tube. The screen does not like being treated like a triode. Even swamping the control grid with a 50 ohm dummy load wouldn't require this much drive to reach the needed grid RF voltage. This will require some pictures of the underside, to determine what is going on.
 
That doesn't seem right at all. Even if the amplifier is cathode driven, it's way too much drive and the wrong way to use this tube. The screen does not like being treated like a triode. Even swamping the control grid with a 50 ohm dummy load wouldn't require this much drive to reach the needed grid RF voltage. This will require some pictures of the underside, to determine what is going on.

Yes thank you. I was going to say that the 4CX250B only needs 2 watts for full output when grid driven and the screen cannot handle ANY power. I have used them in FM broadcast driver stages and they blow easily with any screen dissipation. As you say even if cathode driven that power input is beyond ridiculous. At 1500 watts I am surprised he can keep a pair of them in the sockets.
 
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At 1500 watts I am surprised he can keep a pair of them in the sockets.


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73
David
 
I'm not really surprised by the output. I had a John Boy with a single 250b. It would easily make 750 pep with a cobra 148 driving it. 250 watts of drive seems like 10 times too much.
 
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I'm not really surprised by the output. I had a John Boy with a single 250b. It would easily make 750 pep with a cobra 148 driving it. 250 watts of drive seems like 10 times too much.
I believe one of my locals is driving a 250b johnboy with a stryker. I think hes feeding it around 70 watts pep.
 
As Shockwave said, even with a 50ohm resistor to ground. No more than 80-100W pep is needed to drive amp. Usually the bias is fairly low on those as well, so would need even less. I’ve used 100 ohm going to grid and it didn’t need but 15W pep to get full power out of a pair. At $200 a piece plus shipping from RF parts, it’s going to get expensive quick.
 
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2x4CX1500B's
 

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Yes thank you. I was going to say that the 4CX250B only needs 2 watts for full output when grid driven and the screen cannot handle ANY power. I have used them in FM broadcast driver stages and they blow easily with any screen dissipation. As you say even if cathode driven that power input is beyond ridiculous. At 1500 watts I am surprised he can keep a pair of them in the sockets.
11 meter physics again
 

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