I would not buy anything from MFJ! Why the big hurry, wait to find a good transformer, they are around. What ratings are you looking for?
Is it supposed to fit on the deck over that big hole? Fair radio used to sell a nice oil filled Collins transformer, 2250 volt ct at 650ma, 110 or 220 primary. With a variac that would give 0 to 1500 volts. Its always much better to go with choke input, much better voltage regulation, much lower startup surge current. With a cap input, the voltage will increase quite a bit, but will sag big time under a load. For small supplies with steady loads, that is ok, but for big supplies with loads that vary its not good. On key up, a cap looks like a dead short till it charges up, a choke looks like a resistance in series with the voltage...a big difference... What are you going to run off the supply? 8UF is not very good for a modulator, I always go around 40UF for energy storage. The old Bill Orr handbooks have loads of great info about power supplies in them. Brett N2DTS > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling > Sent: Tuesday, December 05, 2006 11:12 PM > To: Discussion of AM Radio in the Amateur Service > Subject: [AMRadio] Pw Supply > > I am not having much luck finding a HV xformer for my power > supply so an > idea occurred to me that I would like to pass around. > > MFJ has a 900v one for about $100. Is there any reason why I can not > use two of these and tie one side of the secondaries together > and call > that the center tap and have an 1800v ct transformer/s? > > I am using 866's so I must have a center tap. > > Second question is: > > Mine has the HV going to the choke and then to two 4 mf 3kv caps in > parallel. Is it not more conventional to put a cap on each > side of the > choke or two chokes for a choke input filter? > > What would I gain or lose by moving one of the caps to the HV side? > > Thanks, > > js > > > -- > PHOTO OF THE WEEK: http://schmidling.com/pow.htm > Astronomy, Beer, Cheese, Fiber,Gems, Sausage,Silver > http://schmidling.com > > ______________________________________________________________ > AMRadio mailing list > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Partner Website: http://www.amfone.net > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected]
