[AMPS] ?? on 3-500Zs

[W6NQ]

I felt it necessary to clarify comments on this subject, thus offering MY
opinion on 3-500Z series tubes currently available.

For the period 1992-1998, 3-500Z & ZG tubes returned to RF PARTS (RFP) for
warranty during the first year of usage was approximately:

           Amperex         2%        3-Z500Z /8802
           Eimac          2-3%        3-500Z & 3-500ZG
           RFP                2%         3-500ZG
           Taylor          2-3%         3-500ZG

Except for Eimac 3-500Z, all tubes are graphite anode.
RFP & Taylor are copies of the Eimac 3-500ZG and are carefully checked for
quality at factory before shipment  to RFP.   RFP then inspects each tube
before boxing to assure low failure rate.    (Rejects are returned and sold
to someone else.)    RFP 3-500ZG  come with an Extended Limited Warranty of
2 years.
Taylor is 1 year.    Eimac & Amperex, being NOS, carry a lesser warranty.
RFP & Taylor are available as matched pairs.

Regarding comments by an RFP salesman, I have to believe he was not that
familiar with differences between the brands, and have difficulty in
believing he meant to say "don't buy our brand".

In any event, he should have commented that Amperex does have an edge in
quality over other tubes currently available.  Also, he should  have pointed
out that the RFP tube is advertised as the "best value" in 3-500Zs.

As a sidenote, there are some Chinese tubes of questionable quality and
after sale warranty(?).   Also, counterfeit 3-500Z (or G, ZG, etc.) having
Eimac and RCA silkscreened names.  You can  identify them easily, at they
have a s/n stamped on the grid shroud.  The number starts with 98xxxxxxxxx
(=1998), etc.   I think these are being sold mainly to South America.
Buyer Beware--when you buy transmittimg tubes, know the reputation of the
seller and obtain a written warranty you can trust.

There were some bogus Amperex, also.  The real Amperex tube is the only one
which actually fused the glass to the anode connection terminal.   All
others use a detachable anode terminal.    Late issue Amperex used flat
anode ribs/fins.  All other graphite anodes taper to a point.

If anyone has one of these counterfeits, I would like to learn as to where
purchased, etc.

--------Merit   W6NQ


-----Original Message-----
From: zeitler@ibm.net <zeitler@ibm.net>
Date: Friday, June 11, 1999 7:56 AM
Subject: [AMPS] ?? on 3-500Zs


>>    I have a question on using a Eimac 3-500Z  with a 3-500
>>from China. I am going to put them into a Kenwood TL-922.
>>Would I run into any problems doing this?
>
>
>Hi Boyd,
>I just made a visit to RF Parts in San Marcos this past wednesday. I will
be
>procuring a new 3-500Z but I am still not sure which brand. The chinese
>tubes labeled "RF Parts Co." have an unconditional warantee for the first
>year and pro-rated the next year. New price is $120 each.
>
>They also have Amperex which are made in France. They sell for $190 per
>bottle and have a 90 day unconditional warantee.
>
>They also carry NOS Eimac 3-500s for $220 each. I do not remember what the
>warantee was.
>
>I asked the salesman which brand had the lowest return rate and he said by
a
>wide margin the Amperex. He strongly recommended if I was to buy new then
do
>NOT buy their own brand or the Eimac--go with the Amperex. Keep in mind the
>return rate for the "RF Parts" chinese tubes is very low, much less than
5%.
>Interesting enough he said the company sees more returns on the Eimac than
>the other two.
>Lane Zeitler
>Ku7i



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