[AMRadio] SB-221 to SB-220 Conversion

Sun Oct 3 13:59:08 EDT 2010

You are very correct. However if he has a SB221 it can be changed to a SB220 
similarly.
I sold my SB220 and kept the SB200 as I could tell little on air difference with 
multiple signal reports. 

I wish it had 160 on it so I could put Ecuador on 160 this winter. Well I will 
try with100 watts.
Don

________________________________
From: rbethman <rbethman at comcast.net>
To: Discussion of AM Radio in the Amateur Service <amradio at mailman.qth.net>
Sent: Sun, October 3, 2010 10:55:12 AM
Subject: Re: [AMRadio] SB-221 to SB-220 Conversion

  I think we've got apples and oranges here.

The SB-221 and the SB-220 are 3-500Z amps!

The SB-200 and the SB-201 are 572B amps!

Bob - N0DGN  (Former SB-201 owner - Now an Amp Supply LK-500ZB - two 
3-500Zs)

On 10/3/2010 11:42 AM, Donald Sanders wrote:
> Lee I didn't see another reply so here goes. The SB221 is the same as the 
>SB200.
> The band switch has a stop to be removed to allow the switch to go to the next
> position for ten meters. In the input there is a filter to prevent 10 meter
> exitation that has to be removed. You may have to add the input coil and
> capacitor. I can look at my SB200 and tell you what they are. Heath sold a kit
> to add 10 meters.
> BTW Harbach Electronics sells the bandswitch wafer in ceramic for the final
> bandswitcch for $35 in case you should need one. I ordered the PS kit and the
> soft start and am waiting to receive them now. My SB200 has the original parts
> from the 60's so it's time to upgrade the PS, though it still puts out 600 
>watts
> with a bit more HV drop than I like. Those are old electrolytics in the PS. It
> is amazing that the old CETRON 572Bs are still working well. Rugged tubes.
> Don W4BWS/HC4  
>
>
>
>
> ________________________________
> From: LEE BAHR<pulsarxp at embarqmail.com>
> To: Discussion of AM Radio in the Amateur Service<amradio at mailman.qth.net>
> Sent: Sun, October 3, 2010 1:19:31 AM
> Subject: [AMRadio] SB-221 to SB-220 Conversion
>
> Can the conversion of a SB-221 be made to a SB-220 from readably available
> parts?  I am in the market for an amp for my club W5DRC.  I was and still
> might be looking for a SB-200 that looks clean in which I could install the
> Harbach updates and wind up with a nice amp.  We want 10 meters on the amp.
> That was our initial plan.  However, a friend of mine just contacted me and
> said he has a nice SB-221 he would sell me.  But, the amp doesn't have 10
> meters on it.
>
> I think, to make the conversion I would need an input coil, a changed out
> input wafer switch and a tank coil wafer switch and then tap the 20/15 meter
> coil .  I can't find anything on the internet how it actually would be done
> or if it can easily be done.  I don't find anything in the FILE section
> either of this group.  If I can't fairly easily put 10 meters on the SB-221,
> I need to tell my friend I am going to pass and look for another amp.  I see
> Harbach sells a wafer that would work for adding 10 meters to the tank
> circuit.  I would think the input coil would not be too hard to duplicate,
> but the input wafer may be hard to find or very costly making the conversion
> not worth while.
>
> Does anyone on here know what can be done and procurred for the conversion?
> Frankly, I was suprised to not be able to find anything about doing this on
> the internet.  I do realize Heath once had a conversion kit available, but
> my chances of finding one of those would be slim to zero these days.
>
> One last thing, are the Chinese 572B tubes sold with the Taylor name on them
> from RF Parts any good these days?  Those tubes scare me if we wind up with
> a SB-200.  (I know a couple years ago the Chinese 572Bs were bad news and
> the Svetlana tubes were really made for audio and had smaller plates on them
> so they were not really good either.  Plus the fact the 572Bs in a Heath amp
> lie on their side causing "sag" with some of the Chinese tubes).
>
> Can anyone help me out regarding all this?  Thanks for the consideration.
>
> Lee, w0vt
>
>
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