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On Apr 18, 10:22 pm, JIMMIE wrote:
I have an HF amp that uses a single 811A in grounded grid. The power transformer smoked. The transformer was from an old TV set I think it was rated at 540VAC on the sec and I ran it into a voltage doubler for about 1300 VDC . Any info on something I could use as a replacement would be appreciated. Jimmie HEY OM: My choice is a MOT, with zero crossing phase controlled primary with lots of snubbers and filters. Put the MOT in a box with a fan. A zero crossing traic opto coupler regulated by a TL431 with an inverter pass transistor. Power the TL431 seperately and make sure your voltage divider resistors can handle the voltage, I use 1 meg 1/4 watt. they can handle about 200 volts a piece. An MOT can put out up to 2400 VDC no load depending on the type. You going to need a 25amp traic at 600prv or more. You can figure the TL431 to regulate that puppy at 1300VDC easy. And the zero crossing traic opto coupler gives you tonnes of isolation. Been there done that. 73 OM n8zu |
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