>From what I've seen on eBay over the last year or so, you will be lucky to get
>$100 each of the Amprex tubes. Eimac's go for about $150 -- but folks seem
>reluctant to buy the French fire bottle.
Probably a "Freedon Frys" thing...
-S
---- John Lyles <jtml@losalamos.com> wrote:
> Larry
> Have to tried emailing Covimag and asking them this question about mu? It
> appears (?) that they are no longer owned by Richardson, but still supply
> tubes to them. Covimag is one of the few manufacturers of quality 3-500Z
> remaining, the Amperex variant - since Triton was unable to make/sell the
> Eimac design. However, they cannot be paired with Eimac versions for the
> obvious reason you have pointed out.
> 73
> John
> K5PRO
>
> > Message: 9
> > Date: Thu, 31 Jan 2008 08:36:47 -0800
> > From: Larry <larry@w7iuv.com>
> > Subject: [Amps] More Amperex 3-500Z
> > To: AMPS <amps@contesting.com>
> > Message-ID: <47A1F91F.1020700@w7iuv.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > 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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