[R-390] replacement tubes

[Roger L Ruszkowski]

Alex,

A lot of the problem is an alloy, purity quality control in manufacturing
issue.
Some one said use a made over there tube if its the last one on the planet.

The 3TF7 and 26Z5 are not large use items.

Before production begins a minimum number must be planed for production to
cover
cost per unit ( up front engineering setup) then cost of materiel is
considered.
then cost to produce and test. Some big lot needs to be "manufactured"
to make the cost per unit reasonable.

Now you need a "Factor"

The manufacture is not in the charity, loan and investment business.

Who pays engineering set up cost?
Who buys the raw materiel?
Who will acquire the tube we make?
 The "Factor"

Who stores tubes until sold to wholesaler?
Who wholesales tubes today?

Between gee I wish I could get one and here is one
is a whole middle man industry to deal with the logistics
of making it so.

Behind Picrad on the bridge is whole damn star ship to make it so
at his whim.

Back to the Factors. There are lots of them out there.
There are still NOS parts out there lost in old dusty building.
We still see 1946 6C4's popping up today.
The trick is to get these things found and offered on the market.
There are tube brokers out there ask in adds every day for NOS.

Once you get over the logistics, there is still the topic of quality parts
inside the tube.

The folks make an OK audio tube, I have some 6BA6's that are
hot on the tester. And so noisy you can not use them in a R390/A
IF deck at all.
No dough the tube is as offered, but >>> <<< and }}}}
As 26Z5's maybe OK noise is not a factor.
Lets guess about likely to short and tube life.
Lets use your R390/A as a life time test bed for
the first batch of a new model tube off the assemble line.

Hell, Ford has been making cars since 19 ought.
Surly they can get out a new 2002 model this year with out a
major recall. God knows the tires they buy for parts would be up
to speed. Do we not think Ford wants to make a good product.

Same problem with manufacturing tubes.
Would we get lucky with 26Z5's.

The stuff just is not available on planet Earth today to make
good tubes.

US producers are hard pressed to get enough good part stuff
(filament oxide, pure metal that is low noise) to meet their
demands for Military and Broadcast needs. Tons of the
"did not make the grade" stuff run off the assembly lines here
 makes it way over seas to get fabricated into their parts over there.
The demand is not there to keep a quality plant process flowing.
The batch lots churn out so much almost good enough "scrap" in
the start up of materiel flow processes, there is a whole second
world market "recycling the scrap" into almost mill spec product that
is good enough commercial product.

Can you imagine a commercial broadcast station buying a
100KW transmitter tube from the Russian tube factory?

The 3TF7 filament wire is a game of its own.
I am sure the folks could stuff a wire in a glass bottle and
get most of the air out.

Would that wire have the behavior we want?
every tube every time for a life time?

I do not know how we would establish a world demand number
and life period to plug into an engineering guess to help
show the bean counters the return on investment.

Would you like to invest part of your retirement account into an inventory.
That will get sold two at a time over the next 20 years to make a
profit over time on your initial investment.


Alex, the questions are good. The answer is cost to make, store,
distribute, market,
advertize, deliver and sell the items. There is an investment of time and
money in
each of those steps. Each investor wants a fair return on that investment.
The forecast
market does not show a return. The Russian know about 26Z5 and 3FT7 tubes
just like they know about 6L6 and 6BA6 tubes. they make what they make
because
they forecast they can make money on what they make.

You will not see Mc Donald's or Burger King introducing a new product on
the menu
unless studies show there is a bigger return on the new menu item than what
is already
on the menu. You do not introduce some thing new to make less money than
what you
do now. Only X dollars will walk in the door. (Earth is a closed system)
You do not plan
to let more dollars escape out the door to suppliers than is currently
escaping. (less
profit) Same thing with tubes. You have to show the bean counters at the
tube factory that
more dollars can be make from a 26Z5 than from the 6L6 currently being
made. The product mix
is the maximum profit that uses all the parts and all the plant and all the
warehouse that can be
planned. Our pet parts just do not make the cut.

If we hang in and prepare to pay the price some day maybe.
But a 3FT7 is optional
An 26Z5 competes with a 4 cent diode.

Us gee I am a purest who wants a classic are not a large enough crowd to
convert our
fantasies into facts.

Roger.

---------------------------
I recently replaced some tubes in my guitar amp with some of the Russian
made tubes and was surprised to receive excellent results. This gave me
an idea, why hasn't someone approached these tube companies to make a
batch of 3TF7s or 26Z5Ws. This might be a dumb question, but seems
reasonable to me, since the cost is rising to unreasonable levels and
availability of some of our badly needed tubes are getting rarer and
rarer. I suppose that some may raise quality questions but cannot the
companies in question make a "better" quality tube? Just a thought.
Alex