[Amps] stability of amps
jeremy-ca
km1h at jeremy.mv.com
Mon Sep 24 20:00:00 EDT 2007
Peter, the 572B has the same basic form as the 811A which is rated to 54
MHz. Just because Cetron built an audio tube and simply said 30MHz sounds
like a good number doesnt mean its gospel.
The first SB-200 conversion I saw was in the early 70's when one was bought
to me after the owner tried some idiotic magazine article. This was pre
computer so I actually had to do some work to make it fly. The design
evolved from good to perfect as I bought several to experiment with.
I get 55% with good tubes. Output averages 700-750W with 75-80W drive and
some are super "hot" like this last pair.
Unlike the FL-2100B which is probably more popular in the UK, the SB-200 is
very easy to tame on 6. I "discovered" the FL-2100 bogus neutralizing
circuit about 15-20 years ago and W8JI has mentioned it recently as well.
Carl
KM1H
----- Original Message -----
From: "Peter Chadwick" <g3rzp at g3rzp.wanadoo.co.uk>
To: <amps at contesting.com>
Sent: Monday, September 24, 2007 6:55 PM
Subject: Re: [Amps] stability of amps
>I suspect the real question is:
> Does anyone have the s (or y or z) parameterts of the 572B at frequencies
> up to 50 MHz and beyond? This would tell you the potential stability.
> My experience with 572Bs is that they are a real wotsit at 10 metres
> anyway, and personally,. I'd avoid them like the plague
> Obviously, Carl can tame them on 6. He's a a braver man (or some would
> say, a better engineer) than I am to attempt it!!!. What sort of efficency
> do you get, Carl?
> 73
> Peter G3RZP
>
>
>
>
>
>
> ========================================
> Message Received: Sep 24 2007, 11:35 PM
> From: "Steve Thompson"
> To: amps at contesting.com
> Cc:
> Subject: Re: [Amps] stability of amps
>
> c.s. wrote:
> !
>> Primary to my problems is the question of stability of the
>> SB200 on 10 mtrs.
> How does the instability show - what frequency is any oscillation at?
>
> Steve
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
More information about the Amps
mailing list