The designer of those amps for the one in mention was an engineer with the last
name of Waldrup. He worked at the airport if I recall. The owner started with
audio amps and got into the communications business. I think Majestic is still
the Motorola boys there in Memphis for business radio, etc.. They were about
the only manufacturer who used sweep tubes grid driven. This came from the
audio amp business IMO. The only others I've seen made this way used smaller
receiving tubes or audio tubes like the 8417 and a few 6550's. They were done
in Indiana though. Really, being beam tetrodes or power pentodes, which ever
you want to call them, grid driven was the correct way to run them. Most all
the others ran them G-G with all 2-3 grids to ground. Some used a small screen
voltage and some with a controlled bias. The grid driven ones using the tubes
in mention ran about a 900-1000 VDC on the plate, about 400-450 VDC on the
screen and a variable -120 to -150 on the control grid. (4)
M-2057's or 8908's would do about 1100-1200 watts PEP. That aint too shaby for
4 glass tubes. There was one amateur amp, wont mention the name, that tried to
use (4) 6LQ6-6JE6's in it but ran them at 1200 VDC and thought they would last,
not hardly. I think it was rated for 1 KW input, I cant remember. There was one
amateur amp that did use I think 10 sweep tubes in it that ran grid driven and
was the Galaxy. I think it ran 6HF5's or something, and was for legal limit.
Some say it worked pretty good, but I've never ran one. There was actually a
design for a 4 tube 6LF6 or 6KD6 amp in the ARRL handbooks in the 70's. I think
it was a G-G amp and ran about 900 VDC on the plate. That era is pretty much
over except for the Italians and money being funneled back to Midland. Or I
heard that Midland owned them, actually two companies there doing it.
Best,
Will
*********** REPLY SEPARATOR ***********
On 4/15/05 at 7:59 PM mike wrote:
>When I was going to Memphis State University I met my mentor/elmer W4GD
>now deceased and somebody else has his callsign now...he taught me
>radio, had a southbend lathe and wound transformers for guys all over
>the world and built 4-1000 amps some what we call doubler bloopers with
>two of of the 4-1000's ...ran one and it would kick a$$ and take names.
>No $hit, back in the late 70's/early 80's we had a severals guys on top
>of the of the honor roll in Memphis...a couple are still there now...but
>our prioritys change...good to here from you again, my old 53y old a$$
>will still try to keep up, but then I"m in a cootke cutter
>subdivision...$ucks....................
>> See Below,
>>
>> *********** REPLY SEPARATOR ***********
>>
>> On 4/14/05 at 8:41 PM mike wrote:
>>
>>
>>>I think it was more the FCC clamping down on the construction of MaCo
>>>amps here... The Lamar Ave. factory was basicaly shut down when the heat
>>>was on...
>>
>>
>> Well, when that happened, I think it was just moved again. That was a
>good bit before the tubes ran out.
>>
>> OBTW and there was a guy in West Memphis,AR
>>
>>>that built 3-1000Z amps for the 27Mhz guys of course they did not have a
>>>clue about the power supply requierments.
>>
>>
>> Heh, yup I know who ya talkin about (Pete?) ! Some time back, we seen a
>12 tube 3-500Z on eBay and discussed it here. I wouldn't doubt it might
>have come from there.
>>
>> I wouldn't have got in that business except for one thing. At the time,
>there was absolutely NO work around. It was either do this or bootleg. I
>had to stay because of my fathers ill health at the time or I'd of moved
>up to Chicago or Detroit where my Sis was. After I went to work at ACF, I
>pretty much gave up on this work for good until I became handicapped and
>tried it again. I quickly found to get completely out as you cant compete
>with work out of Italy. Even thought the stuff is cheaply built, that
>group dont seem to care about quality over price. I vowed after that to
>never do anymore work for that group again, and wont. Thing is, it's a
>shame how you might have to stoop low just to make a living. But, things
>changed so I wont be looking back at the latter. Anymore, if they dont
>have a license, I wont talk to them, it's not worth it by any means.
>>
>>
>>
>>>Regards, Mike
>>>Will Matney wrote:
>>>
>>>>John,
>>>>
>>>>When that happened, it shut me down and another business in Memphis,
>>>
>>>Ten.. Not only us two, but several other builders in the US. At the time,
>>>there was import restrictions against Yugoslavia where the EI plant was
>so
>>>we couldn't get any from there. Actually, EI is a Phillips company and
>>>still in business making tubes. It also hurt several guitar amp
>>>manufacturers who still use tubes. In GE's line the 8908 was the most
>>>powerful, and the M-2057 was an 8908 with a 12 pin compactron base. Plus
>>>the M-2057 had a 12 volt heater like the 8950. The M-2057 and the 8950
>>>were called RF amp tubes by GE. I think the 8908 was called an audio amp.
>>>The 8950 was a 6LF6 or similar with a 12 volt heater. Right now, the
>>>larger guitar amps use 6550's which are really a souped up 6V6-GT or
>>>similar. The 6550 has a larger anode and the dissapation is greater. The
>>>guitar amp industry is really all that's keeping tubes alive in the
>>>receiving tube business. However, there are those very expensive tu
>>>be
>>>
>>>> audio amps for the home which I highly doubt move much. Actually,
>>>
>>>that's a business I'm looking at getting into but sell at a reasonable
>>>price. Where I can wind my own transformers helps a great deal.
>>>
>>>>See, when Richardson bought GE, or now MPD, they closed all the line up
>>>
>>>except for microwave. The guy I knew told me they were finishing up some
>>>glass tubes for the military and would be the last. Now that the
>employees
>>>own MPD, it would be nice to see them fire back up and make at least some
>>>of the saleable ones. If they would, I'd sure fire back up in a heart
>>>beat. Especially if they made the 8908 again! The 8950 or the 6LF6 would
>>>be a gem dandy too! All could be used for audio amps and, cough, other
>>>stuff.....
>>>
>>>>My gripe with Richardson was what money they made me eat I had invested.
>>>
>>>I bought enough M-2057's to build up what chassis I had left and quit.
>>>However, I was stuck with a bunch of other parts, especially transformers
>>>which cost a pretty penny! On top of it, I had to go job hunting and get
>a
>>>job at ACF instead of running my electronics shop. They also closed up
>>>CeCo when they did the buy-out where they were the salesman who sold to
>>>all of us in that business. My friend at CeCo (Bernie Guss) had to go job
>>>hunting too.
>>>
>>>>Best,
>>>>
>>>>Will
>>>>
>>>>
>>>>*********** REPLY SEPARATOR ***********
>>>>
>>>>On 4/14/05 at 10:29 AM John T. M. Lyles wrote:
>>>>
>>>>
>>>>
>>>>>Will's story sounds familiar, I have heard similar things about when
>>>>>GE Owensboro closed up. BTW, one engineer from there, works here at
>>>>>Los Alamos now, and I used to love hearing stories of the old days of
>>>>>glass tubes there.
>>>>>
>>>>>Whatever dealings Richardson Electronics has done in the past, they
>>>>>have held out as one of the last big tube distributors along with
>>>>>lots of other parts. They had the vision to do this, while so many
>>>>>small players couldn't foot the bill. I wonder if your venture whould
>>>>>have continued to this day, with NOS tubes from Ge or RCA or whoever.
>>>>>
>>>>>I don't always buy Richardsons tubes because they tend to be more
>>>>>expensive. Like a convenience grocery store here in the states, the
>>>>>can demand the price because of their inventory and quick delivery.
>>>>>If I can wait, I buy many tubes direct from companies like E2V,
>>>>>CPI/Eimac, Thales. But if i am off the air and the OEMs cannot
>>>>>deliver in 2 months, then Eddie R gets my business. It costs us $10K
>>>>>per hour of lost accelerator time.
>>>>>
>>>>>As for engineering, Richardson doesn't have a lot in house now, but
>>>>>they do have some capabilities, through some of their subsidiaries,
>>>>>like RF Gain. Just yesterday, we tested a 200 MHz VHF high band TV
>>>>>pallet, rated 450 watts PEP, with Semelab MOSFETS. We got the board
>>>>
>>>>>from them for <$1K, which is a little over $2 a watt. That is quite a
>>>>
>>>>
>>>>>good deal for linear RF power at that frequency.
>>>>>73
>>>>>John
>>>>>K5PRO
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Thing is, I know the following as a fact because I was directly
>>>>>>involved in it. Back some years ago, I manufactured some "products"
>>>>>>that used the following tubes; 8908, M-2057, 8950, and 6LB6. GE in
>>>>>>Owensboro, Kentucky was the manufacturer of these and the last
>>>>>>receiving tube manufacturer. They were still getting plenty of
>>>>>>orders on a bunch of different tubes. GE though decided to put the
>>>>>>tube plant up for sale and old Eddie slipped in and bought up the
>>>>>>majority of the stock. At this time, receiving tube prices were low
>>>>>>and normal. I was going to place an order for 1200-1500 M-2057's and
>>>>>>called CeCo which was a company owned by Richardson. There, they
>>>>>>told me point blank that since Richardson bought the plant, all
>>>>>>receiving tube manufacturing would cease and desist. Also that if I
>>>>>>bought, they would be no more after this. I had a friend who was a
>>>>>>manager and engineer at the GE plant. I gave him a call and offered
>>>>>>to buy the tube lines for the above tubes. I was told, they cou
>>>>>>ld not sell them, by Richardsons order and the equipment would be
>>>>>>put in mothballs and most likely rust away! Now what did this do?
>>>>>>The price of receiving tubes almost doubled overnight and have gone
>>>>>>up sharply ever since. GE's, now MPD, employees just bought back the
>>>>>>company not too long back. If you ever read their info about it,
>>>>>>they name Richardson as an un-disclosed buyer when this all
>>>>>>happened. Anyhow, I think it was done to monopolize the receiving
>>>>>>tube industry somewhat plus raise the prices very quickly on their
>>>>>>stock tubes. By the way, when Richardson bought the GE plant, they
>>>>>>went around to every other manufacturer who used to make them or who
>>>>>>GE private labeled for like Westinghouse and even RCA and bought any
>>>>>>remaining stocks. I got into a bidding war with Richardson and RCA
>>>>>>over a bunch of 6LB6's still NOS at RCA. Sylvania/Phillips sold out
>>>>>>their remaining inventories along with about all the others.
>>>>>>Westinghouse ceased entirely because they had GE make every t
>>>>>>ube. Westinghouses primary distributor was Elmira Electronics and
>>>>>>they told me what was happening at the same time. Now if there
>>>>>>wasn't some crooked dealings going on here, I dont know what else
>>>>>>you would call them. I think that's called manipulating the market.
>>>>>>
>>>>>>Best,
>>>>>>
>>>>>>Will
>>>>>
>>>>>_______________________________________________
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>>>>
>>>>
>>>>
>>>>
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>>>>
>>
>>
>> Best,
>>
>> Will
>>
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