Carl,
Thanks. Good data points.
Do you have a publication date on that Drake manual? (approx OK)
Can you approximate the date/year you observed the comparative operation
in the SB-220?
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! OTOH, I have quite a few different Amperex TX
tube types that were definitely made in Holland during that period.
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" <larry@w7iuv.com>
> To: "AMPS" <amps@contesting.com>
> 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
>> _______________________________________________
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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
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