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'[AD] Fine old Vacuume tube volt meter - the REAL t'
2005\08\10@150942 by James Newton, Host

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WESTON HEATHKIT VACUUM TUBE VOLTMETER Model V-7 A
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7537575882

Lets see if this generates some discussion: Vacuum tube voltmeters offer a degree of isolation and hardiness that is
unsurpassed in the transistor / FET models.

Agree? No? Why?

As per Heathkit advertisements:

This exceptionally fine vacuum tube voltmeter will rapidly and conveniently
measure AC volts (RMS), AC volts (peak-to-peak), DC volts, resistance, and
db.
One switch controls the function selection, while the other determines the
range to be used. Convenient front panel zero adjust and ohms adjust
controls. Zero center operation within the range of front panel controls. A
low voltage scale on the V-7A provides well over 2¼" of scale length per
volt measured.
High input impedance in a vacuum tube voltmeter is valuable in that the
loading effect of the instrument is negligible, and the circuit under test
is not disturbed nor "loaded" by the test instrument. This, along with the
other advantages of a vacuum tube voltmeter, and especially of the Heathkit
V-7A, were formerly reserved for laboratories because of price. Since the
introduction of the brilliant Heathkit VTVM, however, these advantages have
been made available to all.
It is especially valuable in all electronic applications. Use it to measure
all operating voltages and potentials such as B+ voltage in AC-DC, or
straight AC power supplies; filament voltage; bias voltage; AVC voltage;
line voltage, etc. Ideal for measurements in all types of AM, FM and TV
circuits.
To check discriminator or detector operation - AVC or AGC performance - use
the ohmmeter to measure circuit continuity, circuit resistances, to test out
individual components with resistance measurements, or to trace out circuit
wiring through cables or chassis openings. Adapted for printed circuit board
operation, the model V-7A is now better than ever.
Gradual modification of our time-proven VTVM circuit over the years has
resulted in a trouble-free "polished" circuit which can be depended upon for
maximum accuracy and stability. A 6AL5 tube operated as a full wave AC input
rectifier permits 7 peak-to-peak voltage ranges with upper limits to 4,000
volts. Just the ticket for TV servicemen. A voltage divider in the 6AL5
input circuits limits applied AC input to a safe level. This circuitry, and
isolation of the meter in the cathode of the 12AU7 bridge circuit, affords a
high degree of protection for the sensitive 200 microampere meter. Extensive
operational coverage is afforded by 7 AC (RMS) and DC voltages of 1.5, 5,
15, 50, 150, 500, 1500, 7 peak-to-peak AC voltage ranges of 4, 14, 40, 140,
400, 1400, 4000, 7 ohmmeter ranges of x 1, x 10, x 100, x 1000, x 10 k, x
100 k, x 1 megohm, and a zero-center db scale.
Separate AC and DC test leads and probes (NOT INCLUDED IN THIS LISTING) are
provided for circuit efficiency, and polarity reversing switch is employed
for DC operation. Most of the V-7A circuit is etched in copper foil and
bonded to high-grade rigid 3/32" XXXP phenolic sheet. This board provides
the circuit, and the components are mounted and soldered to it.

---
James Newton: PICList webmaster/Admin
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2005\08\11@091724 by John Ferrell

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I have the "Allied Radio" version of this instrument. I built in 1955. Somewhere along the way (1970's?) I replaced the electronics board (vacuum tubes) with a circuit from a datasheet using a linear op amp. It has worked flawlessly ever since the mod. No power line requirement, no warm up time, no zero drift. I find the analog display easier to read from a few feet away.

Mine uses three connections, I think they are common, DC volts and AC + Resistance.
The DC probe has a 10 megohm resistor  in the probe handle.

The internal construction is very open. The switches are open frame should they ever need attention.
The precision resistors are easy to access since they are on those switches.

It is a lot more rugged than a Simpson 260, the standard of the era.

John Ferrell
http://DixieNC.US

{Original Message removed}

2005\08\11@100522 by Russell McMahon

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Not *THE* trains I hope.

       http://russell.servepics.com/temp/train1.jpg
       http://russell.servepics.com/temp/train2.jpg
       http://russell.servepics.com/temp/train3.jpg
       http://russell.servepics.com/temp/train4.jpg
       http://russell.servepics.com/temp/train5.jpg

The ones shown on ebay you are allowed to sell.

> WESTON HEATHKIT VACUUM TUBE VOLTMETER Model V-7 A
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7537575882
>
> Lets see if this generates some discussion:
> Vacuum tube voltmeters offer a degree of isolation and hardiness
> that is
> unsurpassed in the transistor / FET models.

VT may be more resistant to destruction than semiconductor devices.
FET and VT arguably easier to make a very high input impedance with a
simple design.
Suitably protected FET probably more than a match for most VT's.
FET transconductances can be far higher than tubes.
For some purposes, such as receiver front ends, tubes have been argued
to provide far better intermodulation performance. (7360? . 6360
drifts out of the recesses of my mind but that may well be spurious.
Grey fog - I think that's a dual transmitting tetrode. Some keen types
may have used it as an Rx front end.

           RM



2005\08\11@105204 by James Newton, Host

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On Behalf Of Russell McMahon
>
> Not *THE* trains I hope.
>
>         http://russell.servepics.com/temp/train1.jpg
>         http://russell.servepics.com/temp/train2.jpg
>         http://russell.servepics.com/temp/train3.jpg
>         http://russell.servepics.com/temp/train4.jpg
>         http://russell.servepics.com/temp/train5.jpg
>
> The ones shown on ebay you are allowed to sell.

*sigh* now I get to explain what Russell is on about...

...he must have clicked on the link below from the VTVM and send that the
same seller is selling other things from the "Newton Estate" which is my
family home. We have retained a professional eBay seller who lives in that
area (Oregon) to clear out the place. Lots of old stuff is being auctioned
off. Included in that are a batch of old trains of one sort or another.
Russell knows from his visit to me here in California that I have two LIVE
STEAM, working, train engines (O scale and standard gauge) which my father
build over a number of years. As the pictures above (touché Russell) will
show, they are irreplaceable works of art if only because they represent the
best of my father. They will not be sold. One of these days, I will fire
them up and make a movie of them under their own power just so I can brag
about them.

And Russell, nice job on that first picture... You didn't have one of me
that was less flattering?


{Quote hidden}

My dad swore by them.

---
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2005\08\11@114928 by Tim N9PUZ

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James Newton, Host wrote:

> *sigh* now I get to explain what Russell is on about...
>
> Russell knows from his visit to me here in California that I have two LIVE
> STEAM, working, train engines (O scale and standard gauge) which my father
> build over a number of years.

Those trains are *very* cool. I have a lot of respect for anyone who
can do mechanical work like that.

Tim

2005\08\11@131008 by David Minkler

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James,

Those are beautiful!  Thanks to Russell for sharing them.

Dave

James Newton, Host wrote:

{Quote hidden}

2005\08\11@133005 by James Newton, Host

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On Behalf Of Tim N9PUZ
> James Newton, Host wrote:
>
> > *sigh* now I get to explain what Russell is on about...
> >
> > Russell knows from his visit to me here in California that
> I have two
> > LIVE STEAM, working, train engines (O scale and standard
> gauge) which
> > my father build over a number of years.
>
> Those trains are *very* cool. I have a lot of respect for
> anyone who can do mechanical work like that.

Thanks Tim, and I agree! I'm very proud of him and them. They are what is
left of him now that he is gone.
http://www.massmind.org is what will be left of me (I hope) but I can't help
but feel like the trains, being physical objects, are better to remember him
by.

Anyway, one of these days, I have to learn enough about them to fire the
little suckers up. I'm scared to death to damage them so I will probably try
to run them on compressed air first (I know he did that) and not actually
fire them until I really understand small steam engines very completely.

Anyone in SoCal with experience in that sort of thing?

---
James Newton: PICList webmaster/Admin
jamesnewtonspamKILLspampiclist.com  1-619-652-0593 phone
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2005\08\11@144245 by PicDude

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On Thursday 11 August 2005 12:29 pm, James Newton, Host scribbled:
> Anyway, one of these days, I have to learn enough about them to fire the
> little suckers up. I'm scared to death to damage them so I will probably
> try to run them on compressed air first (I know he did that) and not
> actually fire them until I really understand small steam engines very
> completely.
>
> Anyone in SoCal with experience in that sort of thing?


I'm on a few machining lists (mills, lathes, CNC, etc) on yahoogroups, and I
have seen many discussions on engines.  Perhaps you might get some good
info/leads there.

Cheers,
-Neil.


2005\08\11@170438 by Spehro Pefhany

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>Anyway, one of these days, I have to learn enough about them to fire the
>little suckers up. I'm scared to death to damage them so I will probably try
>to run them on compressed air first (I know he did that) and not actually
>fire them until I really understand small steam engines very completely.

I often go to NAMES (North American Model Engineering Show) in Michigan
(next year it's supposed to be in Bowling Green, OH). They run the steam
engines off of compressed air there, I think for safety/insurance reasons.

http://www.modelengineeringsoc.com/

>Anyone in SoCal with experience in that sort of thing?

There are some HSM/Model Engineer groups.

Eg. the Chula Vista Live Steamers:

http://www.trainweb.org/cvls/main.html

There's also the SCHSM, but that's up in Orange County.

http://scrap.50megs.com/


>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam.....interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




2005\08\11@192212 by Russell McMahon

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> And Russell, nice job on that first picture... You didn't have one
> of me
> that was less flattering?

Oh - Many! :-)
Beauty is in the eye of the beholder.
I think you looked fine fwiw :-)


       RM


2005\08\16@033419 by Vasile Surducan

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On 8/11/05, Russell McMahon <EraseMEapptechspam_OUTspamTakeThisOuTparadise.net.nz> wrote:
> Not *THE* trains I hope.
>
>        http://russell.servepics.com/temp/train1.jpg

And Russell is the guy from the left side of this picture ?

thx,
Vasile



{Quote hidden}

> -

2005\08\16@042955 by Russell McMahon

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>>        http://russell.servepics.com/temp/train1.jpg
>
> And Russell is the guy from the left side of this picture ?

No - I'm the guy behind the camera.
Man with beard is James.
Man with bright shirt is Rod - went round the world with me and my
wife.

This is me and my longsuffering wife :-)

       http://russell.servepics.com/temp/ruval01.jpg



       RM



2005\08\16@043910 by Russell McMahon

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>> And Russell is the guy from the left side of this picture ?

> This is me and my longsuffering wife :-)
>
>        http://russell.servepics.com/temp/ruval01.jpg
>

also fwiw

    http://russell.servepics.com/temp/ruval02.jpg

    http://russell.servepics.com/temp/ruval03.jpg

    http://russell.servepics.com/temp/ruval04.jpg

    http://russell.servepics.com/temp/ruval05.jpg


A certain pattern emerges ;-)


       RM

2005\08\16@045142 by Alan B. Pearce

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>A certain pattern emerges ;-)

It takes you a long time to turn around ?????

2005\08\16@050058 by Jan-Erik Soderholm

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Russell McMahon wrote :

> > This is me and my longsuffering wife :-)
>
>
> >        http://russell.servepics.com/temp/ruval01.jpg

You *do*
know that a lot of
"interesting" stuff is available at

   http:
//russell.servepics.com/temp/

right ?

Jan-Erik.



2005\08\16@051131 by Vasile Surducan

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On 8/16/05, Jan-Erik Soderholm <jan-erik.soderholmspamspam_OUTtelia.com> wrote:
> Russell McMahon wrote :
>
> > > This is me and my longsuffering wife :-)
> >
> >
> > >        http://russell.servepics.com/temp/ruval01.jpg
>
> You *do*
> know that a lot of
> "interesting" stuff is available at
>
>    http:
> //russell.servepics.com/temp/
>
> right ?
>
http://russell.servepics.com/temp/hh01.jpg

this is very good, I shut some on Les Ramblas.

Vasile

2005\08\16@053945 by Russell McMahon

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> You *do*
> know that a lot of
> "interesting" stuff is available at
>
>    http:
> //russell.servepics.com/temp/

Yep.
I put it there.
Some would embarrass me less if I took it off.
But I won't.
Not to mention the rest of the site :-)

fwiw - the "dress" is a lavalava, usually worn by VERY large Samoan
gentlemen who might not take kindly to anyone casting aspersions
thereon. It was borrowed from a Samoan friend for a special occasion.
Anyone makes rude comments and I'll send him and some friends to visit
:-). (They're generally very nice and gentle people actually, but they
look impressive.)

DL2 is me also - but only as my driving licence shows me.
Unrecognisable as me in real life :-)



       RM


2005\08\16@054508 by Russell McMahon

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> http://russell.servepics.com/temp/hh01.jpg
>
> this is very good, I shut some on Les Ramblas.
>
> Vasile

It's a bronze of (of course) Christ and Simon of Cyrene, outside the
Catholic Church next to the heart achingly beautiful San Juan
Capistrano olde Spanish Mission , which we visited on the way from LAX
to James and Maria's place.

The photo I have taken in the last few years which I arguably (with
myself?) like most is

       http://russell.servepics.com/temp/sotc_.jpg

Also happens to have a religious theme, but it's the photo as a whole
including its context and meaning that I like. It's a portion of a
modern interpretation of the Stations of the Cross. This is from
"Jesus meets his mother" (station 7?). My wife sees a strangely lit
polystyrene dressmakers dummy. I see a picture which touches me
immensely for all sorts of reasons.


       RM


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