Isn't "conventional wisdom" that tube-based amplifiers are inherently more rugged and forgiving that transistor amplifiers, easier to work on or repair in the field, and that tube amps are the "way to go?" Has that changed, and other than price alone, why should I consider the new Elecraft amp over a tube design featuring auto tuning such as the Acom or the Alpha (older 87A or the new 9500)? Lou, W0FK
"Vic, K2VCO wrote: Tube amplifiers are expensive because high power components (HV variable capacitors, high power bandswitches, power transformers, tubes, sockets, etc.) are expensive. In addition, although the basic circuit is quite simple, ancillary circuits to protect the expensive parts and provide functionality like QSK and automatic tuning are needed. Finally, the enclosure is large and must be well-constructed to be RF tight. A homebrewer can build an amplifier relatively cheaply by using surplus Russian tubes and scrounging parts. But you need to know what you're doing, since mistakes can be fatal. Transistor amplifiers are expensive because they are more complex. A KW amplifier may have 8 power transistors, and the protective circuitry may be more complicated than that for a tube amplifier. If you know that you will be driving a 50 ohm load, automatic tuning is simple; just switch in the appropriate lowpass filter for each band. However, transistor amps are unhappy with even a low-to-moderate SWR, so a built-in antenna tuner is really needed. -- 73, Vic, K2VCO Fresno CA" _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
