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Title: HV capacitor woes Post by: KI4THX on September 08, 2017, 01:03:15 PM Hey guys, Im currently changing over a Henry 3K Classic (3cx1500) to a capacitor input power supply and have hit a snag. The current oil filled caps will be to small to use once I get rid of the choke filtered supply (16MF) and not meet the voltage requirement i will be putting on the tube (3500VAC X 1.4 =around 5200VDC unloaded). Where in blue blazes can someone find another oil cap to replace the old one ?
Any ideas or help is much appreciated ! Title: Re: HV capacitor woes Post by: KF7WWW on September 08, 2017, 02:17:20 PM Contact W7TFO.. Probably has what you need..
Or I'll see what I have in the shed if he cant help you. Title: Re: HV capacitor woes Post by: KD6VXI on September 08, 2017, 08:27:35 PM Good God, that's gonna be a screaming amp for gain. Better have a good parasitic suppressor in it.
Even the CB crowd limits the 8877 to 4.5 kv or so.... FWIW, I've run 6.4 kv unloaded on a 5 kv oil filled. Sat on a Teflon sheet. --Shane KD6VXI Title: Re: HV capacitor woes Post by: KI4THX on September 09, 2017, 11:52:56 AM I agree Shane, It will be running on (past actually) the ragged edge of the recommended voltage but I got a killer deal on a 1.5A CCS Hypersil from Dahl that I couldn't pass up. I did purchase a 0-280V @ 30A Powerstat to run it down...just a hair. Holy moly, the pictures of it didn't do it justice until it landed on my doorstep at 78lbs ! So much for mounting it in the original pedestal, going to have to put it in its own box with casters. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
The original power supply in this particular Henry was a customer ordered special build, 5K power supply, the unit was actually built a two piece unit with a separate RF deck factory. Kind of neat, I've not seen another example like this anywhere. The voltage was already around 4800VDC unloaded, so a few extra hundred volts shouldn't make much difference (I hope). Originally it had a 3cx1200 also, but I swapped that out with a 3CPX1500A7 last year. The CPX version should handle the slightly higher voltage it will be given. Ive owned another Classic MKII X with the 8877 in the past, and at 4500-4600VDC legal limit tone was attained with about 40 watts drive. I actually had pretty good luck running a little DX-40 straight into it, Ha ha ! A couple days ago I added Gigavac HC-1 vacuum relays (four total- one for bias, one for input and a double set for output) and ordered a QSK sequencer board from harbauch (sp?) Electronics. I really hate to string a ton of electrolytics around in the cabinet, but I might if I cant find what I need to give me proper C in an oil variant. Any and all advice is welcome and appreciated ! |