Hi, Bill I was also going to ask if you have a choke input filter -or if you could change the PS filter configuration to choke input to help a bit with the HV.
Also, check your line voltage - especially at night when the load on the electric grid drops. I've seen my 240 VAC here get up well past 265 volts at night! Use a trusted, well calibrated volt meter and take some voltage readings at different times of day to get a feel for what the line regulation looks like! Note that a 10 % increase in line voltage would increase that HV from 825 VDC to over 900 VDC. 10 % high line is not really unusual. Finally, you can check with your local PUC - there are regulatory limits to how much the AC line is permitted to vary - but I'd start with the power provider first. Maybe they need to drop your distribution feeder down a tap at the substation. Excessive voltage is hard on lots of things around your house besides DX-100s! The utility can cme out and put a recording voltmeter on your line for a while to see what's going on, if you complain about excessive line voltage. GL! 73, Charlie, K4OTV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Tom W8JI Sent: Wednesday, January 08, 2014 1:03 PM To: Bill Cromwell; 'topband' Subject: Re: Topband: DX-100 adventure contiunued > I had used four caps rated at 450 volts/100 uF. They were in two pairs > series parallel for 100 uF/900 volts. Some hams cautioned me against using > so much capacitance. So I removed one pair of the caps and ended with 50 > uF at 900 volts. The plate supply remained over 950 Volts until I keyed > the transmitter when it dropped below 900 volts as might be expected. There is actually very little difference in HV PS voltage between tubes and solid state when the supply is choke input. High vacuum rectifiers have about 10-40 volts anode-cathode potential, so there isn't much voltage to be gained. Is this still choke input, and do you have adequate bleeder current? _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
