[AMPS] Floating Grids

[i4jmy@iol.it]

> If the capacitors were low inductance chips mounted directly 
> between the socket and chassis, it would be another story. But 
> adding any long thin leads to the grid is generally a bad idea, 
> whether in series with a capacitor or not.
> 
> The capacitors are just a poor idea that made it into many 
> amplifiers because no one checked the effects thoroughly.     
> 73, Tom W8JI
> w8ji@contesting.com
> 

As I told in my message, all depends by the tube and its socket.
When a tube socket is mechanically unsuitable for short, low inductance 
ground connection, or inside the tube itself there's a long lead 
(inductance) to reach the grid, there's practically no difference if 
the "bridge" from socket pin to the ground is made with a bare wire or 
using a proper capacitor with short leads involving the same total 
lenght, and probably a larger equivalent diameter, of a wire jumper.
It remains the fact that DC grounding grid with a bare wire or a strap 
in SB220 and TL922 without adding a proper circuit for protection is 
not the safest procedure and doesn't enhance anything in practice about 
gain and stability.  

73,
Mauri I4JMY



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