[Amps] (no subject)

[R.Measures]

On Feb 5, 2005, at 4:51 AM, George KB2Z wrote:

> Good morning all,
> I'm new to the list and had a couple of questions that have been 
> bothering me for awhile.
> This one is a bit off, but would anyone have an answer to why 2x3-500 
> amplifiers in gg configuration sometimes have 1,2, or 3 caps 
> paralleled to the grids, some have a choke paralleled to the caps, 
> some are tied directly to ground?
> I have seen schematics of same series amps done with the caps and 
> coils and without. As an aside it looks like Japanese versions of some 
> of the same amps have the grids tied directly to ground. ( HL-2k)   Is 
> it a spectral purity FCC thing?

No, because a 3-500Z is quite linear up to c. 420mA of anode-I without 
any kind of RF-N feedback.  .  In fact, transceivers are not even close 
on IMD to a 500Z.

> As an aside, The Japanese HL-2k schematic shows a choke in the 
> filament return and the US version does not. I'm guessing the choke is 
> for balancing but cant figure why the amp with the grids directly 
> grounded has the filament choke(Japanese) and the floating grids (US) 
> dont.
> I have been looking and cant seem to find the answer. If someone could 
> comment or suggest a place to look for the answers it would be 
> appreciated.
> Thanks in advance, George KB2Z
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org