[SixClub] SB-200 6 meter conversions

[KB0NLY]

I had an amp on 6m running 572b's, while it would make power it seemed to oscillate and tuning was very touchy.  After a while of fighting it and talking to many other conversion owners I determined it was the best I was going to get out of it.  The tubes just aren't worth a darn at 6.  They glow red at 10m, pushing them higher in frequency they would look hot enough to melt.  I tried a new set of tubes, Taylor 572b's, and they did a little better, some more mods and adjustments helped some of the problems.  Eventually I got fed up with it and sold it.

I then had the opportunity to operate a station that used a SB-200 converted to a single GI7BT russian triode.  Tuning was nice, clean output, very stable and easy to use.  I decided to build my own but couldn't get an affordable candidate for parts by this time.  I ended up finding a Yaesu FL-2100B that was damaged while being shipped, the meters smashed, a small dent on one back corner of the case.  I bought it and started to gut it and rebuild it.  A couple months of weekends later I had a half gallon amp that is very user friendly.  I only have one thing I would like to improve on it and that's a fan upgrade, the current AC fans In there are pretty low flow and I want to swap out for one or two higher output muffin fans.  However in its current configuration it doesn't get too hot to concern me.  I usually only push it to about 300w for casual use, though I have driven it to 500w a few times.

http://kb0nly.info/6mqro.html

One of these days I think I might actually get adventurous and build an amp using a pair of GI7BT's and see if I can get a full gallon out of them.

73,

Scott KB0NLY






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From: "Tyrone Burns Sr." <tyke1954 at yahoo.com>
Sent: Monday, May 24, 2010 7:46 AM
To: <sixclub at mailman.qth.net>
Subject: [SixClub] SB-200  6 meter conversions

>  Sometime last week, someone asked about a 6m conversion for the SB-200 other than the QST version. I happen to have a copy of the Ham Rado (now defunct) magazine article that i converted  to .pdf from .jpgs that someone had posted somewhere. ( they are totally differnt articles - the HR version has some  parts mfr. research pages added to it .)
> 
> below is a link to my Yahoo group, where  i uploaded  the articles that I have collected and converted to .pdf.
> 
> 
> http://groups.yahoo.com/group/amateur-radio-amps/files/6%20meter%20conversions/
> 
> 
> 
> They are in order of publication  and I added a comment page and schematic,  from WZ1V - Ron Klimas on some upgrades that he made to the SB-200 during his conversion.
> 
> I have read, many negative comments on various sites about not using 572bs on 6m.  with "King Conversions" being the forerunner.  It seems that supposedly, the 572b does not like  anything above HF. I couldn't say,  i haven't had one there yet.  i do have a SB-201 which  i intend to put on 10m and 6m only (if i can get back to work, so i can have funds o start the project!!!).
> 
>   Anyhow, if anyone would like, i can also send the file directly to you.
>   
>   BTW, feel free to post  your 6 meter amps projects to my Yahoo group.  All amplifier info is welcome!!!
> 
> P: you must join the group to use the site!!!
> 
> 73
> 
> TYRONE J. BURNS SR. - N5XES
> 
> "QRP???.....DuHHH.....QRO!!!!!"
> 
> 
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