[Amps] 6146 via 572b's

Carl km1h at jeremy.mv.com
Tue Oct 12 14:16:24 PDT 2010


----- Original Message ----- 
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
To: <amps at contesting.com>
Sent: Tuesday, October 12, 2010 4:58 PM
Subject: Re: [Amps] 6146 via 572b's


> ORIGINAL MESSAGE:
>
> On Tue, 12 Oct 2010 15:12:28 -0400, Robert Morris <robrk at nidhog.net>
> wrote:
>
>>
>>The added complexity is the need for  screen and bias power supplies.
>
> REPLY:
>
> Another complexity is the need for neutralization on a non-passive grid
> driven amp. If you only have five watts, passive grid is pretty much out
> of the question unless you want to use a relatively high value
> passivation resistor, but then you will probably run into instability
> problems and will need a matching transformer besides.
>
> It might be possible, but tricky.
>
> I think a neutralized amp would be a better choice.
>
> 73, Bill W6WRT


Ceramic-metal tubes generally dont require neutralization unless the layout 
gets sloppy.  OTOH traditional circuit grid driven glass tubes usually do 
require it.

A small CB amp as an IPA would do nice to drive a healthy passive grid 
tetrode or three.

Carl
KM1H



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