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Author Topic: ALS-1306 vs Al-1500 down to a decision  (Read 31960 times)
G3RZP
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« Reply #15 on: December 30, 2015, 11:46:03 AM »

How much 'serious demand' would be needed? By that time, it is likely that there won't be many - if any - 12 inch wafer plants around, just as 4 and 6 inch wafers have been superseded. You would pay a LOT of money to have whatever the then processes are tweaked and you would be unlikely to have to buy less than 4 or 5 wafers which are maybe by then 15 or 18 inch. So unless the demand was phenomenal, it may well not be economically viable.

Plus we have seen a lot of semiconductors appear from China with obsolete part numbers on them that bear no relationship to the real thing.

I don't say it will get like that, but personally, I wouldn't risk it.
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KK4YDR
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« Reply #16 on: December 30, 2015, 12:26:16 PM »

I wished I had the technical expertise to build my own amplifier. However, I don't but that doesn't mean in five years of studies etc... I won't be able too by then.
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KM4AH
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« Reply #17 on: December 30, 2015, 12:55:55 PM »

If I was going to buy any of that series of Ameritron it would be the AL-82 , simply because of the price of the tubes. Plus they are comparatively hard to hurt.

I have lost a few 8877's and it gives me indigestion.
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KD8MJR
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« Reply #18 on: December 30, 2015, 01:15:00 PM »

How much 'serious demand' would be needed? By that time, it is likely that there won't be many - if any - 12 inch wafer plants around, just as 4 and 6 inch wafers have been superseded. You would pay a LOT of money to have whatever the then processes are tweaked and you would be unlikely to have to buy less than 4 or 5 wafers which are maybe by then 15 or 18 inch. So unless the demand was phenomenal, it may well not be economically viable.

Plus we have seen a lot of semiconductors appear from China with obsolete part numbers on them that bear no relationship to the real thing.

I don't say it will get like that, but personally, I wouldn't risk it.

I doubt there would be any demand!  The amount of MRF-150's floating around will most likely outlive all the equipment that uses them.  I was just saying that I thought Carl's statement that 8877 would be available long after you could find an MRF-150 is completely unrealistic.   As for the plants and wafer size, even if it's 40" wafers in the future, all that would mean is one wafer would have a huge yield, if there is a lot of demand then that's not a problem.  Although I think a much more likely scenario would be one that is just like how most Ham radio tubes are made today.  If there is a market for older semiconductors most likely some foreign third world company will buy out old plant equipment and keep on making them in limited quantities and retool after enough is made and move onto another in demand antique product.

I never even got into the area of parts substitution because I think you will still be able to find a genuine Motorola MRF-150 still in the wrapper for a reasonable price even 40 years from now.

73s
Rob


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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
G3RZP
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« Reply #19 on: December 30, 2015, 02:10:38 PM »

Rob,

I'm not so sure. Back in August 1963, the UK Ministry of Defence - Admiralty gave Plessey Research Caswell Ltd a contact for £15000 (about $36,000 then) to develop a logarithmic amplifier integrated circuit, the Plessey SL521. £15,000 was around five and half senior engineers salary for a year at that time. The SL521 was a roaring success, copied by the French, RCA, Analog Devices, Raytheon and we believe, the Russians. The UK MoD collected over £4million in royalties before it was taken out of production in 1997: a Japanese firm offered £4 million for the design rights and the production line - and the stupid management at the time turned them down because they said 'it would divert too much production engineering effort'. The company no longer exists and the plant is heap of rubble now.....

So by 2005 or so, there were a number of companies world wide scouring the planet for SL521s. Or even the SL1613, the same chip in a 8 lead mini DIP. At that time, enough for someone who could have reproduced the bipolar process enough to have probably sold two or three 40 batches of six inch slices. A South African firm were offered 500 at $100 each from Hong Kong: the devices had the correct marking and the correct number of leads, but most of them were way out of spec 741 op-amps if they did anything at all........and the Chinese company disappeared and the bank account closed before the South Africans could stop it. If the parts had been good, the South Africans would have taken at least 5,000 at $100 a pop....The economics at even 120 slices wasn't apparently even enough for Analog Devices to resurrect their copy...........

So are there enough MRF - 150 devices currently out there that are genuine meet-spec-parts? Who knows?

BTW, I was the Applications Engineer at Plessey Semiconductors who had to explain to the customer that he had been well and truly swindled........not one of my happiest days of customer interaction!
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KD8MJR
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« Reply #20 on: December 30, 2015, 02:53:59 PM »

Peter I completely understand, sorry to hear that you guys got swindled, it seems to be the norm today to do this kind of thing in China.  I do not think that the MRF-150 is in a similar class to the SL521's.  The Sl521 sounds like it was for a niche market as opposed to a very popular RF market that adopted the MRF-150 as one of the most popular amplifier transistors made. It has certainly found it's way into a lot of products.

On the far end of the popularity scale you have the 8080 processor, in all these years it never ceases to amaze me that you can go on eBay and still buy a NOS for a few bucks.  Unlike the MRF-150 I cannot see any practical use for it except for restoring vintage equipment just for looks, but it does show the stock pile of these things that are lying around.
Unlike tubes you can store a heap of semiconductors in boxes and not have to worry about breakage or leaks etc.   IC's can be stock piled from 1974 and they still work fine today.  Heck if worst comes to worst and it's the Zombie apocalypse time  Grin maybe future electronic engineers trying to restore vintage equipment may become dumpster divers, scouring through layers of  land fill looking for thrown out vintage gear and then scraping them for parts.  Good thing is that most of the semiconductors will probably still work just fine.

BTW if you guys had only needed a few, the SL521 are on eBay, so somebody must have had a stock back in 63.

http://www.ebay.com/itm/Qty-1-Plessey-SL521C-Wideband-Log-Amplifier-IC-Metal-Can-NOS-/141684018411?hash=item20fd068ceb:g:df8AAOSw7ThUgMYN



73s
Rob
« Last Edit: December 30, 2015, 03:14:09 PM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
G3RZP
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« Reply #21 on: December 30, 2015, 03:21:31 PM »

Rob,

We didn't need them - we made them. Around an average of 75,000 a year for 34 years.....without the ones the others made. Used in various versions of the Sparrow AAM, one version of the Sidewinder AAM, some of the standard AAM, various IFFs.......and a load of marine radars. I still have one of the original 1.75 inch slices of them.....And they weren't cheap, either.

Quote
BTW if you guys had only needed a few, the SL521 are on eBay.

I don't doubt that one can buy devices marked as Plessey SL521 on eBay. What I do doubt is that they actually are contain a chip that is Plessey chip number AZ001......

I do have affair number of the genuine plastic SL1613C devices though, if anyone wants to make an offer.....

One of the interesting semiconductor obsolescent devices is the tunnel diode: they fail because even at room temperature, because of the very high level of doping, the doping profile and thus characteristics change over time.

We did make some transistor arrays, guaranteed for a life of 30 minutes - at 260 degrees C. They were used in oil drilling heads and, if I remember correctly, were about $120 a pop back in the late 1980s.
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KE4XJ
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« Reply #22 on: December 31, 2015, 03:02:26 AM »

I would advise you to do what I did - get the Ameritron  AL-82.  Full  1500 watts out, rugged and instant on 3-500Z tubes. Less expensive than AL 1500 or AL 1200. Tubes should be easily available  for the near future - 15 years or so.  The AL-82 is easily driven to 1500 watts out, but does require more drive as frequency increases. Relatively broad banded. Relatively cheap beast.

I have had very good experience with MFJ/Ameritron products.

If I were to go Solid State, then I would consider SPE Expert amp 2K-FA.
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KK4YDR
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Posts: 673




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« Reply #23 on: December 31, 2015, 09:36:30 AM »

I would advise you to do what I did - get the Ameritron  AL-82.  Full  1500 watts out, rugged and instant on 3-500Z tubes. Less expensive than AL 1500 or AL 1200. Tubes should be easily available  for the near future - 15 years or so.  The AL-82 is easily driven to 1500 watts out, but does require more drive as frequency increases. Relatively broad banded. Relatively cheap beast.

I have had very good experience with MFJ/Ameritron products.

If I were to go Solid State, then I would consider SPE Expert amp 2K-FA.

There are so many amplifier options out there but man some are exotically expensive i.e. Alpha and ACOM. I think the more I look at it I am going to buy used. I have actually been heavily eyeballing the AL-82 the last few days now and find it funny you and another or two have recommended that amplifier.
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W8JX
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« Reply #24 on: January 03, 2016, 04:46:33 AM »

I would advise you to do what I did - get the Ameritron  AL-82.  Full  1500 watts out, rugged and instant on 3-500Z tubes. Less expensive than AL 1500 or AL 1200. Tubes should be easily available  for the near future - 15 years or so.  The AL-82 is easily driven to 1500 watts out, but does require more drive as frequency increases. Relatively broad banded. Relatively cheap beast.

I have had very good experience with MFJ/Ameritron products.

If I were to go Solid State, then I would consider SPE Expert amp 2K-FA.

There are so many amplifier options out there but man some are exotically expensive i.e. Alpha and ACOM. I think the more I look at it I am going to buy used. I have actually been heavily eyeballing the AL-82 the last few days now and find it funny you and another or two have recommended that amplifier.

The AL82 is one of the very few 3-500z amps out there that use PROPER cooling for the tubes in the form of envelopes around tubes with cooling air force through socket first to cool pins and then over tube evenly. It is arguably Amertrons sturdiest/best built amp and hard to damage too. The AL1200 is very rugged too but costs a good bit more. 
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--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
WA2VUY
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Posts: 469




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« Reply #25 on: January 03, 2016, 06:57:31 AM »

Other important factors: what kind of operating do you intend on doing (changing frequencies in a contest constantly? ), are all your antennas resonant? , will you require an automatic tuner also? ), di you intend to operate rtty full power?
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KB4MNG
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« Reply #26 on: January 03, 2016, 07:56:22 AM »

The AL82 is the way to go. The tubes are still available and the originals will more than likely outlast you. I would not buy anything with a $1400 tube.

If the other solid state amp has good reviews that is what I would pull the trigger on. Solid state no tune is so nice if you band hop.
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KK4YDR
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Posts: 673




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« Reply #27 on: January 03, 2016, 01:53:19 PM »

Thanks so far.

Not a contester. Have a legal limit bt1500a Palstar.

Im a rag chewer. And I dont qsy much. I tend to float on one or a close set of frequencies all the time.
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NK7Z
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Posts: 2525


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« Reply #28 on: January 03, 2016, 03:59:55 PM »

The AL82 is the way to go. The tubes are still available and the originals will more than likely outlast you. I would not buy anything with a $1400 tube.

If the other solid state amp has good reviews that is what I would pull the trigger on. Solid state no tune is so nice if you band hop.
I went from an AL-82 to a ALS-1306, yes instant tune is wonderful, just be sure either have a fast tuner, (Palstar AT2KD, or autotuner), or resonant antenna...  I have a review of both amps at:
AL-82:
http://nk7z.net/review-ameritrons-al-82-amplifier/

ALS-1306
http://nk7z.net/review-of-ameritrons-als-1306-amplifier/
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Thanks,
Dave
Amateur Radio: RFI help, Reviews, Setup information, and more...
https://www.nk7z.net
KM1H
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Posts: 5550




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« Reply #29 on: January 03, 2016, 04:15:04 PM »

Quote
Well it is a Eimac tube and VERY rugged. It is likely to last you a lifetime unless you are very very young. A pair of 3cx800's cost more and are a lot more fragile. While a Chinese 8877 is about 700 today I would not bank on that in future and they are easier to damage too. It will be a long time before all FM stations using 3cx1200 stop using them as it is a very rugged tube and cheaper than switching to SS and which can cost a lot to fix in broadcast down time and funds while you can swap a 3cx1200 out in minutes and be back on air if a lighting strike takes it out.  And when that day comes years from now, there will be a lot of surplus tubes around from them for a while.

When was the last time you saw a low power AM or FM station with an on site engineer? I do some on call service for some low power AM stations in this area that still use tubes as I have a fairly decent stash and can be on site in an hour or less and charge a hell of a lot less than the contract engineers who may ignore you for days while you limp along on a 100W SS backup or less. Thats how I got this gig after getting a Bauer 707 up after 2 days after phoning the station and complaining about the very weak signal hours via an out of the blue phone call. After a chat with the owner and listing my creds I arrived with a full tube complement and replaced a 4-400A, 6AG7, and 6SJ7; the station never sounded better. BTW, they were running their 10W after dark TX. Word of mouth got me other biz as these local independents stick together.
Ive even brought my Viking II CDC as a loaner and with their crystal and my D-104 they are on the air in minutes for their in town coverage when I have to order parts, have a transformer rewound, etc. Not exactly FCC Kosher but at about 75W, the cover off and a fan on the iron it works CCS and keeps their main advertisers happy. Nobody notices that the day/night power hasnt changed to the usual 2.5 to 25W level as switching over is a PITA.
I modified the audio chain years ago to near BC quality and near the East Coast sound required on 75 so listeners are happy.

Carl
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