[Amps] Different amp recommendations

Jim Thomson jim.thom at telus.net
Thu Feb 9 07:23:41 PST 2012

Date: Wed, 8 Feb 2012 16:14:12 -0500
From: "Carl" <km1h at jeremy.mv.com>
Subject: Re: [Amps] Different amp recommendations

Check Palstar and QRO, dont know what their specs are but a 3 holer "export" 
model should do it.


##  palstar is now commander.  the HF-2500E has  3 x  3CPX-800A7's in it... but it uses the same HV supply ! 
It will do 3.5 kw out, but the xfmr is maxed to the peg, and then some. the 3 holer qro and commander can't be sold in the
usa...only exported. 

##  the QRO 3 x holer uses  3 x russian  GU-74's  [ '4cx-800'].  The damn thing sucks 675 ma on idle = blast furnace.
225 ma per tube.  [450 ma for the 2 x holer]. 

##  the new commander uses  3 x Eimac 3CPX-800A7's   which is a heck of a LOT of $$  to re-tube the amp. 

##  Nothing wrong with the AL-1500/1200/ AL-82.  they will run 2 kw out all night long, a buddy does just that every night
on ssb.   In a rtty contest,  ur not on TX all the time..so duty cycle is down quite a bit.   Just crank up the fan speed to max
on those amps.....if using rtty..and maybe back off on the power..like  down to 1.2 kw 

##  as for the 91b  having  the HV + fil winding on the same xfmr...IMO, that's  more fubar engineering.  That's the 
dumbest thing u can do, it causes  more grief than u can imagine.  The fil  xfmr should be separate.  The fil xfmr could
contain low V  control  stuff..like  for relays etc... and that's  it. 

later... Jim  VE7RF

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