I have decided to put a 4CX800 in the MLA2500 sitting on the bench. I don't have a copy othe old QST (96?) article on doing this, but I remember seeing that they used some sort of regulator board to
Hi Douglas this is a very bad idea. The IMD performance of any tetrode is dependant on good screen voltage regulation. The dynamic regulation of the plate supply is pretty bad and this obviously caus
OK Conrad - thanks for the feedback. I read what you just said, but I don't understand why the screen would have a problem. I vaguely remember seeing something like this on a web site. Was it the mea
Maybe this article on the SVETLANA web pages may be helpful. http://www.svetlana.com/docs/TechBulletins/TB.html Look up number 19, "New Life for MLA-2500" Mark N1MT@yahoo.com -- Douglas Snowden <Doug
Hi Doug, if you read the Tech notes on the G3SEK page there is a technical explanation but basically ANY variation in screen voltage will wreck the IMD performance of a tetrode and thus produce socia
It was not Rich's idea. Eimac recommends a shunt screen regulator for smaller tetrodes. I used the circuit in two amplifiers and dynamic screen V regulation was better than 1%. A caveat: Operate zen
I wouldn't use that system. It has too low a grid drive, and that's really bad news for modern exciters. The screen supply has crummy regulation, and the transformer is over-taxed by the supply. The
That 's true. Why? There is no reason it should cause problems if you wrap around the zeners with few transistors. The series resistance of a string of zeners might be too large compared to the dyna
With good quality zeners, the screen regulation is ok. Cheap zeners are not a bargain. Unsliced bologna. A string of 5w / 20v zeners can handle anything up to a pair of 4-400Cs (800v). - Rich..., 80
--Original Message-- From: measures <2@vc.net> To: Conrad Farlow <conrad.farlow@virgin.net>; Douglas Snowden <Douglas.R.Snowden@noaa.gov> Cc: AMPS <amps@contesting.com> To: <amps@contesting.com> Date
Regulation will be much better than 1% if you wrap around the zeners with a gain stage. The overall cost will be the same, since you can use cheap HV NPN or PNP transistors and smaller zeners. In th
I remember now why I first mentioned the zener diode string method. I used the idea from measures web page on a pair of 4CX250's on HF. It worked fine, although I never did any measurements for regul
To: <amps@contesting.com> How good does screen regulation have to be? The TS-830s has a not-regulated screen PS. This produces c. 5% regulation on SSB. . However, the resultant IMD is better than an
Smaller zeners have more dynamic R. true blarney - Rich..., 805.386.3734, www.vcnet.com/measures. end -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrativ
we My groups TS830 is, indeed, excellent. As far as I know, GW4FRX does not sell regulators, although he did publish some articles and designs on the subject. Steve -- FAQ on WWW: http://www.contesti
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Wed, 11 Apr 2001 16:10:41 +0100
John did the measurements and faxed me the screen dumps. I prepared the bar charts and the web page on my site. A few additional points: 1. The "need" for good screen regulation will depend on the ty
Possibly the mu g1-g2? Intuitively, one would suspect high gm tubes to be more critical. Again, intuitively, it could explain why some tubes are better in a G2DAF than others. 73 Peter G3RZP -- FAQ o
Message text written by measures not-regulated screen PS. This produces c. 5% regulation on SSB. < Try comparing like with like. The TS-830 does not use a small ceramic tetrode with an enormous prope
.....and all amplifiers need those kits according to who???? 73, Tom W8JI W8JI@contesting.com -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative reques