Carl wrote:
> I believe that goes way back to the "if one is good then 2 must be
> better phrase"
>
> Since a single ended 100TH, for example, couldnt make a KW on CW then
> using a pair solved the problem. It actually goes mack to the original
> discovery of PP or parallel tubes sometime in the 20's or earlier.
>
> Its also a lot easier to run a pair of 8877's then stepping up to 3 kW
> + Pd tube such as the 3CX3000A7 which is a drive and filament power
> hog. The tube of choice then is the YC-156 which has its own issues.
>
> And for the cost involved 3 or 4 813's can make some serious RF. I use
> 4 in one of my AM amps.
And they are relatively cheap and available. I saw a bunch of them for
$25 each last week.
Remember the "sweep tube" amps of the 70's? AKA the GLA1000 and a bunch
of others.
Thats when tubes were really cheap and plentiful.
73
Roger (K8RI)
>
> Carl
> KM1H
>
>
> ----- Original Message ----- From: "Bill, W6WRT" <dezrat1242@yahoo.com>
> To: "Roger" <sub1@rogerhalstead.com>
> Cc: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>
> Sent: Thursday, December 03, 2009 4:21 PM
> Subject: Re: [Amps] Advice
>
>
> ORIGINAL MESSAGE:
>
> On Wed, 02 Dec 2009 22:13:02 -0500, Roger <sub1@rogerhalstead.com> wrote:
>
>> Tubes should always be used as a pair,
>> except for 813's and 572's and then you use 4 of them.
>
> REPLY:
>
> First time I've ever heard "tubes should be used as a pair". I have
> heard the
> opposite: "If you need more power, don't use two tubes, get a bigger
> tube".
>
> Care to elaborate?
>
> 73, Bill W6WRT
>
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