I totally agree with your assessment here Hsu...the manufacturer's marketing folk have seriously misjudged their pricing point! The marketplace is still awash with dirt-cheap excellent quality Russia
All good points you make here Alek. Apart from the el-cheapo design and construction economies made in the entry level Ameritron AL-811 series amps, the 811A was indeed a good tube, as was the 572B/1
Personally I wholeheartedly concur with your sentiments here Bill; most of my shack amps are of the ceramic tube variety and indeed do seem to last forever. My only exception amp is the venerable Ken
G'Day Jim, In answer to your question my amplifier running the Russian GU-74B tetrode / so-called 4CX800 tube is now in its 12th year of faultless service and still makes full rated power. Similarly
No Carl, I just have a stingy reading Bird 43 PEP power meter with needle stiction and dicky peak-hold time constants...what's a few dB between friends anyhow? :-) Australia's archaic and anachronist
Steve, Whilst the GU-84B has become harder to source and relatively expensive nowadays, it is in my opinion one of the finest linear SSB AB1 tetrodes in the 2500 Watt plate dissipation class ever mad
All good valid points that you make here Kevin. There is also an equal fascination / obsession in some ham radio quarters with IM3 and levels! We are talking here of HF amateur / ham band transmitter
Hi Jim, I largely agree with your good points raised here. In respect of times when there's a crammed ham band chock full of brain dead contesters, I simply turn the rig off and come back to the oper
Yes same here in Adelaide South Australia Alek; rarely do I hear or see on the Rx bandscope anybody's spurious IMD crud. We are indeed fortunate to be living in relatively uncrowded geographic region
No, do not use woven / braided conductor for this purpose; it is lossy at the upper HF bands and will run noticeably hot in QRO amps. The best interconnection is made with thin flexible copper strap,
Hi Jim, I fully concur with all of your points below. Someone would have to have lost all of their good sense to even consider buying an amplifier without a complete set of detailed schematic diagram
Well Dick that backorder scenario is merely an indication that folk like SS amps and because there's currently not many well designed high-performance rugged and bullet-proof SS amps in the market to
That sensible criteria Joe just about excludes all solid-sate commercial amps that are currently in the ham-market...rather sadly :-( Leigh VK5KLT Given SPE's own IMD test results at 1 KW PEP - not e
Charly, sadly there's an over-hyped obsession out there about Tx purity and associated IMD specs for ham rigs.... Having said that many current SS amp offerings are poor performers in this regard whe
Yes indeed Joe. The VRF-2933 FETS are good / arguably best of breed in today's generation and offerings of modern RF Power semiconductors. The key to success here is de-rating the combined module's P
Yes indeed Jim; I concur with all you say here. Folk should well be disappointed with this mediocre SS amp. See my earlier post today on my design philosophy for clean SS MOSFET amps. Leigh VK5KLT Ch
Absolutely correct Joe...that's why when I design a VRF-2933 based MOSFET amp for 1500W PEP it's built for circa 2.4 kW saturated Po. This is no mean feat; and makes the practical implementation of t
Sounds fine John. The principal requirement here for Tx tube longevity with indirectly-heated cathode is not to draw any plate current during the 3 minute heater warm-up and emission stabilization ph
Sounds like the tank matching is not optimised for realizing a higher power output Clark. The tube probably wants to see a lower plate impedance transformation or a plate load value presently outside
I agree with the spot-on-the-mark sentiment summary expressed below. A very fine QRO legal-limit S.S. amp with decent IMD specs can be homebrewed by the savvy hands-on experimentally inclined (not ma