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RE: OLD Tube Pleasures



Subject: 
            RE: OLD Tube Pleasures
       Date: 
            Fri, 14 Mar 1997 22:26:38 GMT
       From: 
            robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: 
            Society of Manufacturing Engineers
         To: 
            tesla-at-pupman-dot-com



The =Esteemed= John Freau responds to Robert Michaels:

T>Robert, All,

T>Yes, truly there is another wonderful world of coiling in the tube
coil
T>realm, and you post many good reasons why this is so.

T>Having built a number of tube and spark gap coils, I'd like to make
one
T>comment:

T>Regarding constuction, set up and tuning, I always find tube projects
more
T>difficult and time consuming than disruptive coils.  I'm speaking here
about
T>new designs, not replicating other's designs.  In a spark-gap coil,
assuming

        I stand partially corrected.  Thank you.  In the case of
        =original= tube designs, the neophyte (especially) may find
        them more difficult.

        As a working (and long practicing) electrical engineer - born
        and bred in the vacuum tube era - such is not so for me.
        And nowadays, computer programs exist which make the process
        duck soup:  plug in the tube characteristics (or just the type
        no.!) answer a few questions, and out pops a design.

T>an experienced builder and "normal" coil parameters, there are only a
T>few main things to adjust; gap, ballasting, tune point, and coupling.
T>And these adjustments do not tend to interact too much, at least not
T>to a "overly sensitive" degree.

        Your point is accepted.  I recall the posting of (I believe)
        one Richard Quick on how he cobbled up a crude coil one
        morning just to be able to have the ozone from it to
        deodorize an old refrigerator.

                BTW -  Whatever happened to Mr. Quick?  Was a
                frequent poster.  Usually more literate and
                knowledgeable than most.

                He used a .sig of "...throw another megavolt across
                it".  Did he throw one too many megavolts across
                something?  He is missed.

T>In the tube coil on the other hand, especially large (26" to 36"
sparks)
T>ones, adjustment and set up is super-critical.  Yes, a quickly cobbled
system
T>may produce some sort of spark, but optimal performance requires a

 [ ... ]

        Agree.  To an extent.  Tube coils are by definition, sedate.
        "26 - 36-inch sparks" are almost a contradiction in terms
        in the realm of tube coils.   =If= a person were intent upon
        achieving such,

                1) - I'd admire his ambition.

                2) - Yes, it would be difficultly attainable


T>time-consuming, trial and error balance of; coupling, tuning, grid
T>feedback grid leak resistance, and also calculated or trial and
T>error matching of the tube to the power level, matching of tube to
T>tank impedance, etc.  If just one element of this synergistic dance is
                                                    ^^^^^^^^^^^^^^^^^
        OOooo! I like that.  You write with as much verve as I
        do (almost).

T>out of step, the results can be disasterous -- one eye must be kept on
T>the spark while the other is observing the tube plates, and all the
T>while the ear is listening for the proper full-throated "power-roar"
T>which often heralds tube coil synergism and kick-butt output.

        I think "disastrous" is a tad bit overstated.  There are
        things to watch out for in tube =and in= spark-gap coiling.
        (But as said, I've never played in the "36-inch league"
        with tube coils).

T>which often heralds tube coil synergism and kick-butt output.
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

        Yeh! You do write with verve.  (personally, I use OLX -
        "Off-Line Express")
                                        Regards,

                                        Robert Michaels - Tough
                                        Enough to Coil in - Detroit, USA