Good point George. The question was specifically about the 813 and it's a "nostalgia bottle" for many of us. It was popular after WWII because you could get them for as little as 50 cents each in the USA. Even in the 60's they were still available 'surplus' for a few dollars. Typically the socket cost far more than the tube.
The biggest cost in a tube amp is in the power supply (including high voltage hardware) and in the input/output network components that can handle the voltages involved. You can avoid those costs by buying a used amp, even if it's not functional (but hopefully has a good power transformer). Other than learning to work around thousands of volts (only one mistake allowed per lifetime) tube amps are extremely simple things compared to most high power solid state amps. And tubes tend to be much more tolerant of abuse than solid state. But that comment about only one mistake allowed per lifetime around the typical tube amp power supply was serious. I'm always very cautious about encouraging today's typical ham to mess around with even moderate or low power tube gear if he/she has "grown up" around solid state running from a few tens of volts at the most. One needs a wholly different set of procedures, concerns and attitudes to work around even a few hundred volts safely. Over the years we've lost a number of wonderful, bright, prolific designers and builders in the Ham community to one momentary mis-step around a high voltage power supply. Ron AC7AC -----Original Message----- Just some simple questions. Why use an 813 for an amp. 125 watt plate dissipation, 50 watts of heater power, and a large physical size. The "modern" 572b uses 25 watts for heater power has 225 watts dissipation and is cheap. I have two SB200s they put out 800 watts PEP and they can be bought real inexpensive. Every couple of years I stick new tubes in them for kicks and use the pulls as spares or "presents". I love building, but I am practical too. But have fun guys and please be careful. George, W6GF ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
