the 3-400 tube was inspired by Art Collins
An engineer in the collins co. designed a GG amp with the famous zero bias 4
811s. Art liked the designed but had a loyalty to Eimac, so he asked Eimac to
develop a zero bias tube that ran a lower anode voltage (1500- 2000 volts).
Eimac never could develop a suitable tube on time, so he went with the 30L1
as is.
A similar amp was made later, the Hallicrafters HT-45 loudenboomer featuring
the new 3-400z
I got this info from a QST article on the 811A
Steven Grant W4IIV
jeremy-ca <km1h@jeremy.mv.com> wrote:
----- Original Message -----
From: "Larry"
To: "jeremy-ca"
Cc: "AMPS"
Sent: Thursday, January 31, 2008 12:53 PM
Subject: Re: [Amps] More Amperex 3-500Z
> Carl,
>
> Thanks. Good data points.
>
> Do you have a publication date on that Drake manual? (approx OK)
April 1980. However further looking finds the exact same info in a 1970 L-4B
manual.
Both manuals state that EIMAC or Amperex 3-400Z's or 3-500Z's are installed
at the factory.
>
> Can you approximate the date/year you observed the comparative operation
> in the SB-220?
Many years thru the 60's to present. I repair amps as well as convert to 6M.
Even these days I will occassionaly get an amp with 60's date codes from
either mfg. Tantalum and graphite.
>
> My 1969 short form catalog also shows the filament current as 14.1 amps.
> It makes no mention as to where they were manufactured but from the
> photos, etc., they would have you believe the manufacturing facility was
> located in Long Island!
Hicksville was a R&D facility with limited tube production capability; I
have a few different TX tubes in my collection. Besides Europe was much
cheaper in those days. They were primarily for SS, varactors, microwave
components, etc. I visited it around the late 60's when a highschool ham
friend ( Im from LI ) was in R&D. Got varactor samples when they were the in
thing for building UHF triplers.
OTOH, I have quite a few different Amperex TX
> tube types that were definitely made in Holland during that period.
I forget who developed the frame grid tubes, Amperex or Phillips or even
Mullard who built Amperex also. All of a sudden they were everywhere and
Drake jumped right on them in the 4 line. I used the Amperex gold pin 6922
in 6 and 2M converters for a short time.
Good luck on your quest, the trail is certainly muddied by now!
Carl
KM1H
National Radio 1963-69
>
> Thanks & 73, Larry
>
> Larry - W7IUV
> DN07dg
> http://w7iuv.com
>
>
>
> jeremy-ca wrote:
>> The Drake L-7 manual lists both brands and expected idling currents.
>>
>> CW and SSB respectively:
>>
>> Amperex 100/160 ma
>> Eimac 170/220
>>
>> As bias is not adjustable in most 3-500 amps it then holds that the
>> Amperex would require more drive to match the Eimac output.
>>
>> OTOH the old graphite Amperex, AND graphite Eimacs, were easier to drive
>> in SB-220's even tho the mu was listed at the same 160 as the tantalums.
>> This has led to endless discussions over the decades!
>>
>> My 1973 Amperex short form catalog does not list the mu but does show a
>> 14.1A filament. That is vs 14.5 for Eimac. It also claims Holland
>> production.
>>
>> Carl
>> KM1H
>>
>> ----- Original Message ----- From: "Larry"
>> To: "AMPS"
>> Sent: Thursday, January 31, 2008 11:36 AM
>> Subject: [Amps] More Amperex 3-500Z
>>
>>
>>> Thanks to all that replied with info. I had hoped there would be more
>>> definitive data, but the mystery still remains.
>>>
>>> Here's what I know for sure:
>>>
>>> In 1969 Amperex was owned by North American Phillips. The 3-500Z *MAY*
>>> have been manufactured in Holland. It may have been inspired by the
>>> 3-400Z but according to the short form catalog I have, it was NOT just a
>>> 3-400 with a bigger anode. There are other differences listed. The Mu at
>>> this time was 200 or more depending on which set of data you are
>>> inclined to believe.
>>>
>>> At some point between 1969 and 1980, manufacturing was moved to France.
>>> Amperex was still owned by Phillips in 1980. It is not known if the Mu
>>> spec was changed coincidently with the move or not. My tubes are date
>>> coded 1980.
>>>
>>> In 1985 or 1986, Amperex was purchased by Richardson Electronics as part
>>> of their world wide takeover of tube manufacturers. It is not clear if
>>> only the name was purchased or if the production facility was included
>>> in the deal.
>>>
>>> Today, The Amperex name is still owned by Richardson. The tube is
>>> manufactured in Brive, France by COVIMAG. It is not clear if COVIMAG is
>>> a subsidiary of Richardson or just under contract for production. If you
>>> go to the Amperex/COVIMAG/Richardson web page (which is not easy to find
>>> by the way) and click on the 3-500Z data sheet, a PDF of the Eimac 1980
>>> 3-500Z data sheet pops up!!
>>>
>>> What is clear is that at least once during the long production life of
>>> the Amperex branded tube that the Mu spec changed. Possibly more than
>>> once. What is very unclear is when these changes actually took place.
>>>
>>> If current production tubes are built to the Eimac spec, then the RF
>>> Parts statement that they take more drive is false. If the tubes were
>>> built to the old Amperex spec, then the statement must also be false.
>>> Some folks claim more drive, some say the same drive, but nobody offers
>>> date codes for the tubes they used. The only way they could require more
>>> drive is if the Mu were to be drastically lower or the user failed to
>>> adjust the bias voltage for the proper idle current.
>>>
>>> This matters to me for two reasons. First is that I'd simply like to
>>> know the answer. Secondly I need to know to meet the design goals I have
>>> arbitrarily established for my latest project. Yes, I know, there is no
>>> on-the-air difference to be seen. But I already have a 1200 watt drive
>>> limited amp. The whole object of this particular project was to meet the
>>> 1500 watt limit EVEN THOUGH I DON'T NEED IT!
>>>
>>> It would be easy to plug them in a test but doing so even for a couple
>>> minutes will drastically reduce the sell price if I do wind up selling
>>> them. RF Parts currently lists Amperex 3-500Z's at $269 bux. Ebay prices
>>> on tubes the are NIB with the seals intact will surely approach that.
>>>
>>> Anybody interested at $500 for the pair postpaid USA?
>>>
>>> 73, Larry
>>> --
>>> Larry - W7IUV
>>> DN07dg
>>> http://w7iuv.com
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>>
>
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