• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Easy question about tube data sheet

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Tell me if this is correct.

2 x 6y6ga tubes each get 200v to the plates with 12.5W dissipation each. That equates to 62.5mA that each tube needs.

Let's say these two tubes get B+ through a 6x5gt rectifier that's rated for max rectified current to be 70mA. Certainly sounds like it wouldn't work...

here's the rectifier data: http://www.r-type.org/pdfs/6x5g.pdf


I'm gonna come up with some more stupid questions, I'm sure.
 
Sea Biscuit said:
So they just show a set of data for 135v plate voltage just for the hell of it, and doesn't indicate any sort of max rating?
They tell you that max rating is 200V. 135V is both a recommended screen voltage and, perhaps, a typical supply rail for an AC/DC set in the USA? Or a set with only a heater transformer, but directly rectified mains?
 
I have done some experiments on the 6Y6. It was a long time ago, but more will be coming soon.

The maximum plate voltage rating is 200 volts. It can be violated within reason without serious consequence if the dissipation and screen voltages are kept in spec.

The maximum screen voltage rating is 135 volts. This one needs respect. Some tubes will exhibit runaway or bias creep at 160 volts, while some will eat 200 volts without a problem.

Any time you push the ratings on a tube the grid circuit resistance must be as low as possible. The 6Y6 wants a 100K maximum with fixed bias, which is quite low. If you are going to bend the ratings, you need to be well below that. Cathode follower, mosfet or transformer drive is suggested.

The 6Y6 was developed when rectified wall outlet was common, but the fact that AC or DC heater operation is stated suggests another reason. The 6Y6 was used in aircraft and shipboard equipment where the B+ was derived from a 28 Volt source with a mechanical rotary inverter (Dynamotor). Most of the 6Y6's that I have did come from military surplus.
 
*higher values of capacitance than indicated may be used but the effective plate supply impedance may have to be increased to prevent exceeding the maximum rating for hot-switching transient plate current.


so this means that a resistor should be added in series to the plate if higher values are used?

Not that I plan on using a higher value... just trying to understand.
 
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