EL84 grid resistor placement

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mat
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EL84 grid resistor placement

Post by mat »

Is there any reason to not to place the grid resistor between pins 1 & 2 on the socket of the EL84 ? Like the R21 and R22 on the layout: http://www.turretboards.com/layouts_sch ... iginal.pdf
mat
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Structo
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Re: EL84 grid resistor placement

Post by Structo »

I think the reason they are on the board is that with a nine pin socket there isn't much room to mount components.

What you could do if you wanted the grid stoppers closer to the tube would be to mount a small terminal strip on the socket mounting screw and install the resistor from the strip to pin 2.

I have done that with preamp tubes and it works well.
Tom

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es345
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Re: EL84 grid resistor placement

Post by es345 »

If you look to some data sheets Pin 1 is marked as "internal connection". There is no security that Pin 1 is not connected internally. Therefore I wouldn't use Pin 1.
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mat
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Re: EL84 grid resistor placement

Post by mat »

es345 wrote:If you look to some data sheets Pin 1 is marked as "internal connection". There is no security that Pin 1 is not connected internally. Therefore I wouldn't use Pin 1.
Thanks for the info. It seems that some NOS tubes might have the pin 1 connected but modern EL84's does not. So I'll do as Structo suggested and use terminal strips for the resistors.
mat
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