[Amps] SB-220 HV Transformer Wanted

[Gary Schafer]

No. The amp runs AB2 meaning it draws grid current.

The reason for the CW/SSB switch was to allow tune up at 1 KW DC input on
CW. 
This was the regulation at the time the amp was designed. You were not
allowed to ever exceed 1 KW DC input, even during tune up.
Switching to SSB after CW tune up allowed higher PEP input by maintaining
the same plate load impedance (where the amp was tuned)for the higher power.
In other words the voltage to current ratio remained the same when the
higher voltage was selected.

73
Gary  K4FMX

> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of mark
> bitterlich
> Sent: Wednesday, October 30, 2019 4:23 PM
> To: Joe Subich, W4TV; Joe; amps at contesting.com
> Subject: Re: [Amps] SB-220 HV Transformer Wanted
> 
> Ok, this brings up a technical question that pertains to the topic
> amazingly enough. When you shift from single sideband to CW on this amp
> are you or are you not moving the class of operation from AB1 towards
> AB2 and thus  improving efficiency?MarkWA3JPY



> -------- Original message --------From: "Joe Subich, W4TV"
> <lists at subich.com> Date: 10/30/19  16:36  (GMT-05:00) To: Joe
> <nss at mwt.net>, amps at contesting.com Subject: Re: [Amps] SB-220 HV
> Transformer Wanted On 2019-10-30 3:12 PM, Joe wrote: > Why need
> them?Some people prefer to keep their equipment "stock" or at
> leastfunctionally stock.  The SB-200 was never designed for 1500Woutput
> on CW - it was designed to operate at 1 KW DC input (ca.700 W CW or 1500
> W PEP SSB output).Pushing the SB-220 to 1500 W CW output (or worse,
> running RTTYon the high taps) is a quick way to fry something.  Even
> thetoroidal transformer you recommend is only rated for 800 W!73,    ...
> Joe, W4TVOn 2019-10-30 3:12 PM, Joe wrote:> Why need them?> > Run it at
> the HV side and use less drive and less currents all around.> > The
> CW/SSB switch I converted into a stand-by switch.> > Joe WB9SBD> Sig>
> The Original Rolling Ball Clock> Idle Tyme> Idle-Tyme.com>
> http://www.idle-tyme.com> On 10/30/2019 1:38 PM, Joe Subich, W4TV
> wrote:>>>> >> https://www.antekinc.com/as-8t800-800va-transformer/>>>>
> Unfortunately, this transformer lacks the primary taps for CW/SSB>>
> operation of the OEM device.>>>> 73,>>>>    ... Joe, W4TV>>>>>> On 2019-
> 10-30 10:23 AM, Joe wrote:>>>>>> On 10/30/2019 8:56 AM, Joe wrote:>>>>
> Morning Dick,>>>> If you are not afraid of making a few electrical and
> mechanical >>>> modifications, I would go with this transformer.>>>>
> https://www.antekinc.com/as-8t800-800va-transformer/>>>>>>>> I'm glad I
> did! 1/4 the cost of most drop in replacements. yet MUCH >>>> better
> performance!>>>> Joe WB9SBD>>>>>>