[AMPS] Help building mono band amp
steve
w5set@alltel.net
Thu, 11 Oct 2001 22:01:39 -0500
the 813 amp idea is sound----working anywhere with one hand is just like
working with several of the "fermented products that i won't mention before
starting your project"---damn stupid advise!!
please use BOTH hands WITH BRAIN engaged FIRST!!!! I have been a
construction electrician for years and years and have heard this crap as
long----
and have fought the spreading of this really stupid advise as long too!! i
really suppose all you electronic sages solder stuff together with one hand
or route wiring with one hand---- if i ever catch an electrician trying to
land a wire in a panel with one hand (hot panel by the way---don't tell me
you can TURN all of them off, either, cuz some times you just can't--i.e.
hospital work) i raise hob with them!!!!! this crap has been spread WAY
too long and remember there AIN"T no such thing as an OLD STUPID electrician
(or high voltage tinkerer) they won't grow old!!!
ENGAGE BRAIN---THINK ABOUT IT TWICE---CHECK THAT HIGH VOLTAGE HAS BLED
OFF---THEN AND ONLY THEN USE BOTH HANDS
steve w5set@alltel.net
-----Original Message-----
From: Barry Kirkwood <bjk@ihug.co.nz>
To: Mike Baker <k7dd@qwest.net>; AMPS REFLECTOR <amps@contesting.com>;
Jean-Michel Bombar <jmbombar@graphnet.fr>
Date: Wednesday, October 10, 2001 4:21 PM
Subject: Re: [AMPS] Help building mono band amp
>
>Yep,
>similar 2x813 amp in older "Radio Handbook" by Bill Orr. A proven
performer.
>73 es gl.
>end
>Barry Kirkwood PhD ZL1DD
>Signal Hill Homestay
>66 Cory Road
>Palm Beach
>Waiheke Island 1240
>NEW ZEALAND
>www.waiheke.co.nz/signal.htm
>----- Original Message -----
>From: Mike Baker <k7dd@qwest.net>
>To: AMPS REFLECTOR <amps@contesting.com>; Jean-Michel Bombar
><jmbombar@graphnet.fr>
>Sent: Thursday, 11 October, 2001 6:36 AM
>Subject: Re: [AMPS] Help building mono band amp
>
>
>>
>> Hello,
>> Get an ARRL handbook from say, 1965. For several years there was an
>> article on building monoband KW amps using a pair of 813's. I used these
>> articles as the basis for my very first amp in 1969. 813's are still
>> available via various sources including the internet and are quite
>> inexpensive. I scrounged around for a year or so on e-bay and made a
deal
>> with a fellow to buy 9 tubes and 4 sockets for $80 including the
shipping.
>> 7 tubes were carbon plates (the best ones IMHO) and 2 were the metal
>plates.
>> One broke in shipping (not carbon,no loss). For any band up to 20 meters
>> they kick butt and love high voltage. The book specs say 2500VDC max for
>> the plates but up to 3500VDC is commonly used in GG linear service. 4
>tubes
>> will give you a comfortable KW out at 2.5 to 3KV. For up to say 750 out
>you
>> could use two tubes and have an easier time finding the filament
>> transformer. (10VAC at 10Amps for two tubes) Used a surplus 150pf cap
>for
>> my tuning on 40M and made the coil out of copper tubing. The power xfmr
>was
>> a surplus unit that ran 900VAC at 1A as a voltage doubler.
>> Total cost back then (1969) was maybe $30 but you could still build
>one
>> today for less than a $100 with a little patience and scrounging. The
best
>> part of building is you get to test and refine a bunch of talents. Sheet
>> metal fabrication, wiring or harness making, parts recognition and
>purchase,
>> electronic design, metal finishing/painting, etc. just to name a few.
>> A few caveat come to mind. I mention these to anyone who is
>> contemplating building their first amp.
>> 1. HIGH VOLTAGE is not just a sticker on the side of a cabinet.
It
>> is a seductive lover that will KILL you and bring you to room temperature
>if
>> not respected and the rules of working around it obeyed to the letter.
>You
>> seldom get a second chance let alone a third to violate the rules. I
have
>> been blessed with having survived lethal shocks twice and figure that a
>> third is not likely so be aware.
>> DO NOT put your hands inside a cabinet that has High Voltage
(anything
>> above 24Volts AC or DC) present. The AC power mains kill more people
>every
>> year than any other type of electrocution.
>> Work with one hand in your pocket. NOT leaning on a grounded metal
>> cabinet or desk.
>> Always disconnect the mains power and flag or wrap up the plug end so
>it
>> isn't accidentally reconnected by someone else. (The old story about two
>> guys working on a transmitter together and as one guy has his hands
inside
>> the cabinet, the other finds the plug pulled from the mains and plugs it
>> back in without thinking, saying something like, "OH, I found the
problem,
>> it isn't plugged in; try it NOW!" Room temperature.
>> Use a "shorting" stick or discharge stick. In days of old a large
>metal
>> loop shaped like a large fish hook with a wooden handle and a piece of
>braid
>> with and alligator clip on one end clipped to ground. Today I would
>modify
>> that to be a probe type of stick with a non-conductive handle hooked to a
>> long string of 2 watt metal film resistors with a total value of about
>100K
>> Ohms or so. Use it to check the discharged state of the HV caps before
you
>> start working on the amp.
>> Use a shorting clip across the HV to GND and remove it when you are
>> done. IF, IF someone accidentally turns on the power while you are
inside
>> the cabinet, it will/should blow the FUSE or Circuit Breakers and keep
you
>> from being a dead fish.
>> NEVER, NEVER build an amp without proper fusing of the mains.
>> NEVER, NEVER bridge the safety devices (fuses or breakers). They
have
>a
>> purpose.
>> NEVER, NEVER work on a project involving High Voltage while you are
>> exhausted or overly tired. Falling asleep into your work can be deadly.
>> Too tired and you do stupid things you might never recover from.
>> NEVER, NEVER work on a project involving High Voltage if you are
>> intoxicated. Same result as the previous warning. Save the 807's for
the
>> celebration of a successful days work.
>> All of these previous warnings are old hat and inevitable truths to
>> staying alive while working around High Voltage as I am sure most would
>> agree. Let me add a couple of my own.
>> Realizing that the Human nature of things is to do something as long
>as
>> you can so long as it doesn't hurt you, all of us at some time or another
>> have violated one of the rules listed above. Some of us have survived
the
>> experience. Some of us had Help surviving the experience.
>> If you don't know CPR go and learn it. Once you do you will posses a
>> skill that you may never have to use (hopefully). But the alternative to
>> not knowing it may cost someone their life and it just might be someone
>you
>> love. My personal feeling is that it should be taught in junior high
>school
>> and a requirement for a drivers license. It could greatly reduce the risk
>of
>> death to thousands. Remember, electrocution causes the heart to stop and
>> CPR applied immediately after the victim is clear of the danger can make
>the
>> difference in being back to normal or a "gomer".
>> If you must work on a piece of equipment that involves high voltage
do
>> NOT do it alone. Be sure someone knows where you are and what you are
>> doing. Have a buddy give you a hand. (It can be more fun doing these
>things
>> as a "buddy" project.) There is nothing more unnerving than to have your
>> wife come home and find you "well done" and at room temperature out in
>your
>> garage or in your shack. It ruins their day and yours!
>>
>> OK, I know this all seems like I am describing the obvious, but it is
>> worth repeating.
>> It is sort of like meeting a beautiful woman in a club. YOU ONLY GET
>> ONE CHANCE TO MAKE A GOOD FIRST IMPRESSION! You will seldom get a second
>> chance.
>>
>> Good luck with your amp project. READ, READ, READ, and if you still
>> have questions, at least you know where to ask. In spite of all of the
>> banter and sniping at each other on occasion, this is still one of the
>best
>> resources for information on AMPS. You could never say this group isn't
>> passionate about what they are doing.
>> Again, good luck.
>> Mike Baker K7DD
>> k7dd@qwest.net
>> ----- Original Message -----
>> From: "Jean-Michel Bombar" <jmbombar@graphnet.fr>
>> To: <amps@contesting.com>
>> Sent: Wednesday, October 10, 2001 12:57 AM
>> Subject: [AMPS] Help building mono band amp
>>
>>
>> >
>> > Hello,
>> >
>> > I would like to built my first HF amp, I am thinking of a 1Kw mono band
>> amp
>> > for the 40M band.
>> > Does any of you have any idea of where I could gather informations to
>> start
>> > this project?
>> >
>> > Thanks.
>> >
>> > Jean-Michel, F5MMX
>> >
>> >
>> > --
>> > FAQ on WWW: http://www.contesting.com/FAQ/amps
>> > Submissions: amps@contesting.com
>> > Administrative requests: amps-REQUEST@contesting.com
>> > Problems: owner-amps@contesting.com
>> >
>> >
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> Submissions: amps@contesting.com
>> Administrative requests: amps-REQUEST@contesting.com
>> Problems: owner-amps@contesting.com
>>
>>
>
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
--
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Problems: owner-amps@contesting.com