Tube plate voltage doubts

[TiagoSilva]

Hi,

i'm trying to design an AM radio based on a ECC86 design, but with other tube, because this tubes are very rare and expensive...

My main doubt resides in the triode plate voltage. The datasheet of any tube gives a voltage on the plate and I don't know very well what to take of it.

Ex. If the triode plate voltage is 250+ Volts, what does this means ? The maximum voltage that can be handled by the tube ? The minimum voltage ? The main voltage, meaning that it must be no more no less than 250+ volts ?



Cheers.

 

[crutschow]

The tube data sheet will show a maximum plate voltage for that particular tube. You should never exceed that or the tube may be damaged.

You can (and should) operate the tube below this voltage. The plate voltage somewhat affects the tube gain and distortion so you need to look at the tube characteristics to determine the best operating point for your application.

 

[TiagoSilva]

Thanks Carl.

Since tube datasheets are as rare as the tubes themselves I guess I will be using the EWB (Multisim) to analyse the output value with any specs I find on the internet, I also have an old tube manual... But with unordered schematics...

Any other toughs about this ?

 

[crutschow]

Unless it's a rare tube you can probably find design information for a particular tube on the internet. And certainly EWB can help with simulating the operation of the tube in a circuit.

One thing to remember when simulating circuits is to include stray capacitances as they can affect the circuit's frequency response. You will need to use some "rules-of-thumb" to estimate the values. Tube plate and grid capacitances, for example, should be included.

 

[bloki]

Practically all tube datasheets are here:
Frank's Electron tube Pages
Simulation of tube circuit with EWB requires spice model for specific tube. Existing spice models are limited to most popular tubes.

 

[JimB]

Look here:
ECC86 pdf, ECC86 description, ECC86 datasheets, ECC86 view ::: ALLDATASHEET :::
seems to be plenty of information.

JimB