Joe, If you are going to cathode modulate that 4X1... Consider PDM Digital. You will need twice the plate voltage +20% if you want 120% positive peak audio capability. The 4-125 is the only tube in your list that can possibly hold off the voltage and it's close at that.
FYI: I am finishing up a Class-D 4-1000 PDM modulator for my 4-1000 Class C stage. It's a series modulator that will feed the 4-1000 class C plate and is unique, with a floating cathode pulsed at 110KHz at 7KV. I call it "high-side-PDM". This way a conventional RF deck can be PLATE MODULATED. The grid switcher uses FETS, and the screen supply also floats at the 7KV level. Optical coupling is used to get the PDM stream to the grid fets. If you are interested in such a crazy project, let me know. It will be nice to have digital audio from the class C 4X1 on 80-10 Meters... If it works and I survive the testing process (scared). The rig will be called "4X1X4X1" George AB2KC. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Crawfish Sent: Tuesday, September 28, 2004 11:19 PM To: Discussion of AM Radio Subject: Re: [AMRadio] Home Brew I am trying to figure out how to cathode modulate the 4-1000 I have. I have a pair of 813's and have a 4-125. Have a bunch of 807's and 1625's as well. Joe W4AAB ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, September 28, 2004 6:47 PM Subject: Re: [AMRadio] Home Brew > There are all kinds of good designs in the 50's handbooks. The most > fun you > will have is trying to find all the parts. > > 73, > > John, W4AWM > > << I'd like to build my own AM transmitter. Tube style; more than 200 watts. > > > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected]
