[Heathkit] Grounding the grids of 3-500Z tubes

[rbethman]

The last Heath Amp I ran was the SB-201.  I built it, and it was okay, 
but didn't have the oomph that I needed to link up with the folks that I 
used to talk to in round tables.  I lived a LOT closer to them 
originally.  Now I'm over 600+ miles away by auto using the Interstate.

My current normally used Amp is the Amp Supply LK-500ZB.  This gets me 
back to the original roundtable folks - JUST.

John is correct in the grounding of the grids directly OR with a small 
resistor as a fuse.

I have run the LK-500 on CW, SSB, and AM.  Drive the puppy with 25 to 30 
watts dead carrier and see about 300 - 350Watts dead carrier out.

No issues with switching on/off or any arcing.  The tubes are Eimac.

Bob - N0DGN

John King wrote:
> While I am not an engineer, I take advice from Engineers very well.
>
> <snip>
>
> Collins 30L1 seems to have started the cap/choke design with Heath, Omega, Henry (2K series, which I own one of)and Kenwood TL 2000 following the design. Yes, I know the 30L1 uses 811As but grounded grid design was just copied. My Amp Supply 3-500 amp was designed with directly grounded grids at the socket also. My GSB 201 MK III has directly grounded grids on the four 572B tubes. My experience has been very good with the amps using directly grounded grids, however I like the suggestion of using the small value resistors to protect against momentary shorts.
>
> The foregoing is not my CLAIM to being an expert and isn't attempting to evaluate the engineers who have so kindly assisted me with information. The information supplied to me by BOTH was good and WORKED!!
>
> Several years of use supports the SB220 grid grounding scheme with success. 73, John, K5PGW
>