John, I've corresponded with Richard a few times over the years since the great "War of the Nearly Perfect Amplifier" was waged in the pages of QST, as well as the parasitics articles. His ideas made sense to me, from an engineering perspective, and gave me a lot to think about in the years after I had read them. Nowadays, thinking through the intricacies of amplifier design makes me shudder to think how many really bad amplifiers are out there (both homebrew and commercial).
I used to own a Henry 2K-4 linear amplifier. Said amplifier was quite a handful from a tuning / loading perspective; you'd look at it ever so slightly the wrong way and it would "spit" at you (arc over). Examining the plates & rotors of the plate tuning capacitors indicated that this unfriendly behavior had been going on for quite some time. After rebuilding the capacitors with parts from Henry, I corresponded with Richard on the subject & purchased & installed his parasitic surpressors, negative feedback, and one or two other things; after this, the amplifier was forever after unconditionally stable & cound never be over-driven by a 100 watt exciter (e.g. ALC was no longer needed). I was the third owner of that amplifier; it is now running up hours on its fifth owner somewhere in Alabama. Needless to say, that experience made a believer our of me. I have AG6K kits in hand for installation in my B&W PT-2500A and Alpha 91b amplifiers, when the day comes. IMHO, Richard was treated extremely shabbily by the ARRL in the QST "War of the Nearly Perfect Amplifier". The act of the League trotting out four (I think it was four) very public rebuttals of Richard's articles without any opportunity for review & comment by Richard violates every principle of the peer review process that I can think of; certainly I'll never take the professional risk of writing anything for that magazine. Unfortunately, Richard chose to take the low road instead of the high road, and nowadays attacks his detractors in the newsgroup and mailing list forums. As a result, he now comes across more like a blowhard than the thoughtful engineer that he really is. This attitude doesn't get him any brownie points with the trade publications or commercial amplifier designers. Maybe he doesn't care any more; I don't know. BTW: I'd LOVE to get my hands on a Collins 30S-1. It's design is unique: a cathode-driven class AB1 amplifier using a low-IMD external anode tube with a DC-grounded screen. regards, Mahlon - K4OQ > Message: 2 > From: "John E. Coleman" <[EMAIL PROTECTED]> > To: "AMRadio" <[email protected]> > Cc: <[EMAIL PROTECTED]> > Date: Fri, 27 Dec 2002 18:56:54 -0600 > Subject: [AMRadio] AG6K > Reply-To: [email protected] > > How many of you know of Rich Measures AG6K whose web page is at > http://www.vcnet.com/measures/ > > I don't know the fellow but he has some really interesting stuff on home > brewing and amplifier design. At lot of the stuff is for linear > amplifiers but it could be class C as well. I especial liked the > articles on VHF/UHF parasitic prevention. Care of tubes by proper > regulation and control of parameters and the all too often overlooked > control of filament current inrush and filament voltage regulation also > caught my eye. > > There seemed to have been a disagreement a few years ago between > him and the QST/ARRL people. Not to uncommon, I suppose, when knowledge > meets political corruption.
