[AMRadio] XFMR info needed


CL in NC mjcal77 at yahoo.com
Thu Sep 30 13:53:17 EDT 2010


I recently picked up a Heath HA10 Warrior amp to finish out my Heath station.  Come to find out the PS had been gutted, and rebuilt with only a power XFMR. a full wave bridge rectifier, and about 16uf of filter, which put over 2KV on the plates of the 811's in standby, it pins the meter out.  The missing swinging choke must have met the same demise as the power XFMR considering the amount of blackness that was left under the chassis.

I got some good info here on the UTC S-45 'Special Service' transformer currently in the amp, but, unless I looked at the specs wrong, it is rated at only 200ma CCS.  The original Heath was around 3KV at 500MA with a full wave rect., a swinging choke in the center tap and 8uf of filter.

Was digging in my stuff and found a nice xfmr with a 1100V at 700ma center tapped secondary, some government surplus find from years ago.  The thing is, this surplus transformer is somewhat smaller than the UTC S-45, which has a 750/900 center tapped secondary and only 200ma rating. 

So, is that UTC 200ma CCS rating wrong, did I read it wrong, or did UTC spec out their xfmrs extremely concervatively?  I have not put RF to this amp yet to see how much  the voltage sagged under load, but in it's present form, the regulation won't be there for AM operation

Thanks for any help,

Charlie, W4MEC in NC 


      


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