Rob,
You're welcome!
The way I'm now interpreting your question(s) is less about the Alpha 9500, and more like many of the questions here regarding amp selection....
These are the typical:
"what amp should I buy?" ....
"Solid-State or Vacuum-Tube?" ....
"how good IMD do I need?" ....
"do I need 1500 watts out?" ....
"do I need 100% duty-cycle, no time-limit, 'brick-on-the-key'?" ....
"if I desire a 'tube amp', which tubes should I avoid / which ones to look for?" ....
"if I desire a SS Amp, which devices should I avoid / which ones to look for?" ....
"are there 'no-time-limit' SS Amps?" ....
"what is the 'best' amp?" ....
etc etc.
etc....
And, to be blunt, all of these questions have been asked, answered, and beaten-to-death...over-and-over again....many times here....so, no need to go through all of this again.
A few
brief clarifications...Thank you for turning this into an excellent thread. I will be the first to admit that I don't know everything an extra class is supposed to know. But I do know about IMD distortion and things like that. I also know old technology with tubes is questionable.
Huh?
Actually, "tube" amps almost always provide much better IMD than SS amps!
They are also much more forgiving of operator mistakes.
And, they will generally never need a "tuner", as most will cleanly run full-output into 3:1 VSWR, and reduced power, but still clean, into even higher VSWR's without issue!
And, if you buy an amp with "the right tubes", they will last you many decades!
(not sure how old you are, nor if you need to bequeath your ham gear to decedents, but I have 8877's, 8874's, and 3-500z's that are still CLEANLY putting out full power, and they are all over 40 years old!)
In my business, web hosting and dedicated server leasing, we rely on solid state these days rather than the old Hardware versions. So I'm with you all on that. I was actually leaning towards solid state but always kept coming back to the 9500 as the one to beat. It uses what I have read a single tube, not an 811 if I have read that correctly, but still a single tube that's readily available according to advertisements.
Yes, the '9500 uses a single 8877....which is as far from an 811, as a Ferrari is away from a Yugo!
I'll have to look at that a little bit closer because that will be a deciding factor for me. I like the fact that an instant tune solid state is probably in my future.
If you require "instant-on", there are SS amps, yes....but also tube amps using the 3-500z tubes or the 3CX1200 tube (or the big 3CX3000 tube) are all also "instant-on"!
Smaller,
Some SS amps are smaller, yes...
quieter,
NONE are quieter!
Allow me to repeat that more clearly....almost all SS amps are "noisey" / "loud"!
And, except for the OM Power tube amps, almost all tube amps are quieter!
but can it be a brick on 100% key down and never scream ouch? That remains to be seen.
If your asking this in regards to amateur SS amps? The answer is no....they are none that will do this....sorry. 
I urge you all to keep this thread going because as you do I learn even more. That's one more thing I will readily admit - that I am always open to learning something new. Although I might write a post it seems to lean in a certain direction, I can also be moved in the opposite direction by those that have already invented the wheel so to speak.
I have no desire to "move you in any direction"....just wish to get you some facts....problem is, there is a lot of "generality", but only when you start to define YOUR application / YOUR desire, can anyone start dealing in specifics! 
2) Just to get you started, here are some very brief generalities:
a) I compared many modern amateur HF amps...have a look.
https://www.eham.net/community/smf/index.php/topic,100600.msg809639.html#msg809639b) In general, SS amps cost more $$$ per watt....as well as usually needing a tuner (either built-in or external), unless all antennas present a VSWR of 1.5:1 or less.
c)
General rules-of-thumb of modern Solid-State amateur HF amps:
---- Most SS amps are "instant-on", and require no "tuning" per se....just band-switching....(many can be controlled by the transceiver, providing totally smooth / seamless operations.....and many can also be run remotely, via IP controls)
---- In general, amateur SS amps are not "no-time-limit" / "brick-on-the-key" at 1500 watts / legal-limit out, but rather use some weird / quasi-deceptive marketing (such as "no-mode-limit", or "reduced output after xx seconds", etc.) to imply high-duty-cycle operations. (in actual fact, they are all limited by their cooling capacity / ability to cool the device itself....and, most have temp sensors that fault-out the amp into "standby", once temps rise to their limits....some have "timers" that only allow constant carrier operations for 7 - 8 seconds, before faulting to low-power or standby....
---- Ironically, most modern SS ham amps will run "continuous carrier" at approx 50% - 70% of their rated/advertised outputs....and, this point (50% - 70% of advertised output) is also usually close to the amp's 1-db compression, which generally means that you can figure a linear output at approx the same power, or a bit lower....
{yes, if comparing to legal-limit tube amps, this means that most SS ham amps that are advertised as "1500 watt amps" are really 750 to 900 watt amps....and those that are advertised as "1500+ watts" / "2000 watt max", etc. are actually 1000 - 1200 - 1300 watt amps... }
---- Solid-State amps have worse IMD products than tube amps, many times significantly worse. (although, when looking at the better SS Amps, it is usually the transceiver's IMD that is worse)
---- Most modern amateur Solid-State amps (not their internal device specs, but the whole amp itself) have a 1-db compression point at approx 60% to 75% of their "advertised output" ---- yes, meaning that at their "advertised output", they are not running linearly!
---- The only way to use most modern SS HF ham amps with good linearly, is to run them significantly below their rated/advertised outputs. (although, still not as good as most tube amps)
---- All SS amps will need to be run into a matched load, with VSWR's of 2:1 or less....most will need VSWR's of 1.5:1 or less to produce full output, and anywhere close to clean linearity!
---- Due to the need to cool the device, most SS amps have rather loud (and annoying?) cooling fans.
d)
General rules-of-thumb of modern vacuum-tube amateur amps:
---- In general, tube amps are much cleaner / much more linear than SS amps.
---- In general, only the bigger tube amps (like Alpha) will be 100% duty-cycle, no-time-limit, "brick-on-the-key" at 1500 watts / legal-limit output.
---- In general, tube amps are much more forgiving than solid-state amps in regards to "oppss" moments!
---- In general, most tube amps will run their rated power into VSWR's of 3:1, and many will do into much higher VSWR's.....most will run VSWR's up-to or beyond 5:1 at reduced power, with good linearity and no damage.
---- Some tube amps have almost silent cooling (legacy Alpha's)....but, unfortunately, some are loud, like a jet engine (OM Power).
---- Eimac 8877 / 3CX1500a7 tubes are very linear, very rugged, and will last decades and decades....but if purchased new from Eimac/Richardson are wicked expensive (~ $1800)! NOS (New Old Stock) Eimac 8877's are available for ~ $400 - $500 each, and will also last decades (in storage or in an amateur amp)...
{fyi, I have four Eimac 8877's that are over 40 years old, and still running full-output, and wicked-clean and linear! And, many, many other hams have the same experiences! } ---- Other ceramic-metal power-grid tubes (transmitting tubes), such as the 4CX1500b, 3CX3000, 8874's, etc. are also still made by Eimac, and some are decently priced and some are pricey!
---- 8877/3CX1500a7 tubes made in China (with various "brand names" like Penta, Machet, etc.) are good, and many folks use them without issue for years....although some report slightly worse linearity and longevity, they sell for ~ $800 - $900, new, with warranty....
---- 3-500z tubes (and all glass transmitting tubes these days, and for > 10 years) are all made in China....the "good ones" are sold in the US by RF Parts, for ~ $300 - $350 each, and come with warranty and should last you years of service....
---- other glass transmitting tubes, like the 811a, 572b, etc. are only made-in-China, and have sporadic reliability.....i.e.
ya' pays ya' money ---- and ya' takes ya' chances!As for what amp to buy?
That's a great question....may I suggest you read thru the pages and pages of discussions here....AND make sure you are making a decision for you and for your application / desire, not mine, not others..
As example, if all you want to do is rag-chew on SSB, then you do not need a "brick-on-the-key" amp, as well as not needing "instant-on", or "no-tuning", etc....and, if you're good at repair / circuitry, etc, then you do not need a "new" amp...however, if you're into contesting, or RTTY, etc., then a heavy-duty amp is called for, such as a "brick-on-the-key" Alpha...and, if you need instant-on and/or instant band-change with no "tune-up", then either an Alpha 9500 or a good solid-state amp (Expert 2K, or Flex Power Genius, or Elecraft 1500), might be good choices for you....
But, again, it should be
your choice, based on
your application /
your desire, not mine or others....(the above are just random examples)
I do hope this helps. (please read the many threads here discussing these matters, and assess them with your own application/desire in mind)
73,
John, KA4WJA
Author
Topic: Alpha 9500 (Read 1512 times)