[Amps] Peter Dahl / Harbach SB-220 transformer

[Gudguyham at aol.com]

In a message dated 6/11/2010 9:20:21 A.M. Eastern Daylight Time,  
km1h at jeremy.mv.com writes:

I guess  Jim doesnt understand that more RF places more stress on an 
already  
marginal bandswitch Lou to say nothing about increased gain can result in  
instability as proven in many amps.

Some like to go for the most  meter wiggle and the heck with  reliability(-;

Carl
KM1H

Carl, I would be the first one to agree that the band switch in the SB-220  
is marginal for the total power that a pair of 3-500's can produce.  I  
suppose the thought process by the designers was that since I KWDC input was 
the  "law" and about 600 watts out being the norm, the band switch was fine.   
Moving forward to today's law everyone was kicking the power output up and 
the  band switches were failing.  I would say that about 7 out of 10 of the 
amps  I gut for 6 have a band switch issue with one or more contacts.  
Usually 10  meter contact.  Sometimes 10 and 15.  Although Denny cut corners here 
 and there, he did supply a much better band switch in the Dentron and AS  
amps.  Drake also had a very good band switch, rarely did I ever see a bad  
one.  The bigger Ameritron amps have a good band switch also.  If you  want 
to go for that "meter wiggle" you had better build up for it.  Just  like 
the days of drag racing, MO power, bigger and more HD clutch and gears,  wider 
tires traction, bars etc etc. Lou