[AMRadio] SB-221 to SB-220 Conversion

Sun Oct 3 14:16:23 EDT 2010

Don:

Yes he has a nice SB221.  If I can modify it easily for ten meters the club 
would be happy.  The set screw removal would be great if the input and 
output switch assembly already have the contacts.  (one on the output switch 
and two on the input switch).  I can easily duplicate the input coil and the 
fixed caps on each side of it and also put a strap from the output switch to 
a tap on the 20/15 meter coil and remove the 11 meter trap assy

Lee, w0vt

.
----- Original Message ----- 
From: "Donald Sanders" <w4bws at yahoo.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Sunday, October 03, 2010 12:59 PM
Subject: Re: [AMRadio] SB-221 to SB-220 Conversion

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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