[Amps] Peter Dahl / Harbach SB-220 transformer

[Pete Smith]

Strikes me as the only good way to get more out of an SB-220 - avoids 
stress on the bandswitch and tune cap due to higher voltage.  I wonder 
if anyone has ever combined this with directly-grounded grids, which 
W8JI and others advocate for increased power gain.

With the original grid circuitry, my SB-220 gets just about 1.2 KW out 
on 80 and 40, decreasing to about 900 watts on 10, all with 100 watts of 
drive.

73, Pete N4ZR

The World Contest Station Database, updated daily at www.conteststations.com
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On 6/8/2010 9:56 PM, James wrote:
> Carl, It's an upgrade. I have the Dahl installed. The original supplied
> something like 900 mils, the Dahl 1.3 amps with the same 3.2 kv...but less
> sag.
> Now you don't HAVE to cut the safety screen... some people just let it bow,
> it's just a little taller.
> This is important, however, you  can't just drop the xfmer in. The mounting
> bracket will catch on the lips of the chassis. You have to unbolt the side
> and slide it in that way. You also have to drill new holes.
> Now the 220 was a 1 kw amp. I could get 1.3 If I drove the snot out of it.
> This was on a Kenwood sw2000 meter (and yes meters lie.) After the Mods..
> new caps, diodes, bleeders, and xfmer..I could get 1.6 kw out. Jim KB4RMN
> ----- Original Message ----->  ----- Original Message -----
>    
>> From: "Bill VanAlstyne W5WVO"<w5wvo at cybermesa.net>
>> To: "[Amps]"<amps at contesting.com>
>> Sent: Monday, June 07, 2010 10:45 AM
>> Subject: [Amps] Peter Dahl / Harbach SB-220 transformer
>>
>>
>>      
>>> I'm interested in hearing from anybody who is knowledgeable about the
>>> SB-220 replacement transformer by Peter Dahl that Harbach is offering --
>>> specifically, wehether it has significantly higher power capacity than
>>> the
>>> OEM Heathkit transformer and/or a higher voltage output. They also say
>>> you
>>> have to cut a hole in the inside top cover to accommodate its size, which
>>> is not a big deal for me -- but if it isn't a SIGNFICANTLY more powerful
>>> transformer, there's no real reason for me to shell out the bucks for
>>> one.
>>> I guess the short form of the question is: Is this transformer a
>>> replacement or an upgrade?
>>>
>>> Bill W5WVO
>>> _______________________________________________
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>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>        
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