Hello Jim and group,
I respectfully disagree. Tube amps are not a thing of the past nor will they be
for a long time to come. I would like to point out that I own and use both
Solid state and Tube amps and love them both. Each has its advantage. You did a
great job pointing out the advantages of solid state, I would like balance the
issue by point out the advantages of Tubes.
Obsolescence is been very poor for solid State transistors for both high and
medium power amplifiers. AS a person that repairs amplifiers (both solid state
and tube) for others has (since 1972) been forced to deal with issues like
that. A solid state device that is in vogue today is likely to be “History” in
short 2-4 years or so. Replacement transistors are another disappointment. As
an example Icom 706 MK2g was still selling the radio when the final transistor
became unavailable. A replacement transistor involved modifying the printed
circuit board and to do that required transplanting components to another
place. Tubes on the other hand like 8877 and 3-500 and others, enjoy a long
history of 40 + years and have no end in site. so that makes the Tube amplifier
easer to get repaired.
Another disadvantage of LDMOS is the input side of the LDMOS has a “Glass Jaw”.
If you over drive them it can be a quick death, while a tube will take an
occasional over drive.
Amplifier Life and longevity is strongly on the side of the tube amplifier. If
you want it to last 25 to 40 Years. Do not put all of you eggs into a solid
state amplifier because in 3-5 years you may be faced with owing a “door
stopper” and looking to buy another amplifier. I consider this a very serious
issue. In fact I consider the ability to repair to be the most important issue
for hams that can not buy multiple amplifiers.
Thanks, Bruce, W8HW
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