[Amps] Re-wiring Alpha 77 to use a 4-wire 240 vac cord and plug

Fri Mar 2 10:39:40 PST 2012

I am modifying the shack and would like to bring in a new run of 240 vac Romex. 
The Alpha 77 I own presently uses a 3-wire plug and wall outlet, with neutral 
grounded and the power Xfmr primary center tap also grounded. I recall this 
subject being discussed years ago here but my archive search did not locate the 
answer. I seem to recall the solution was to install a 4-wire plug and wall 
socket set rated for the proper current level and either using the original ac 
power cable which supposedly has 4 wires already or fitting the amp with a new 
4-wire cable and then connecting the neutral wire in the cord to the power Xfmr 
center tap and making sure to remove any shorting strap to chassis ground from 
that point. In addition, connecting the ground wire from the power cord to the 
amplifier chassis. Lastly, wiring the plug and wall socket correctly; two 240 
vac "hots" to their appropriate lugs, plus the 240 vac neutral line to its 
corresponding socket lug and finally the safety ground wire in the cord to the 
safety ground lug in the receptacle. Does this sound correct? I also remember a 
caveat about the safety ground wire is not suppose to carry any normal load 
current. This makes sense since most Romex cable, like "6-3, with ground" have 
in their product description text "3 conductors" and then a smaller gauge 
(larger # ) for the ground lead, in this case 10 AWG. I believe the problem with 
the way this amp was wired from the factory has the 120 vac blower motor wired 
across one half of the 240 vac to chassis ground, thereby requiring the ground 
wire to share the blower motor current with the parallel connected neutral line. 
So short of replacing the 120 vac blower motor (good luck finding one) with a 
240 vac unit wired across the two phase lines, what can be done to meet the new 
wiring code?
Thanks, John

----- Original Message ----
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To: amps at contesting.com
Sent: Fri, March 2, 2012 4:10:33 PM
Subject: Amps Digest, Vol 111, Issue 4

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Today's Topics:

   1. What contry customs drilled the holes? (Charles Harpole)
   2. 432 Cavity Amps;  Thomson TH 331 (John Lyles)
   3. 8877 Amplifier Photos (Jim W7RY)
   4. Re: 8877 Amplifier Photos (Hsu)
   5. Re: I always learn something new on eBay (Alex Eban)
   6. Re: 432 Cavity Amps;  Thomson TH 331 (Mike Andrews)
   7. Re: What contry customs drilled the holes? (Pete Smith N4ZR)
   8. Re: 8877 Amplifier Photos (Jim W7RY)
   9. Amp Supply ATI-6 Tuned Input Boards for sale (Doug Renwick)
  10. Re: 432 Cavity Amps;  Thomson TH 331 (Carl)

----------------------------------------------------------------------

Message: 1
Date: Fri, 2 Mar 2012 05:35:23 +0000
From: Charles Harpole <k4vud at hotmail.com>
Subject: [Amps] What contry customs drilled the holes?
To: <tobias.wellnitz at googlemail.com>, <amps at contesting.com>
Message-ID: <COL107-W17CE03C79436C0BE8913D8F76D0 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"

which nation?

Charles Harpole
k4vud at hotmail.com  
> From: tobias.wellnitz at googlemail.com
> Date: Thu, 1 Mar 2012 17:48:48 +0100
> To: amps at contesting.com
> Subject: [Amps] Customs drilled a hole in my GU74b / 4CX800s
> 
> Hi,
> 
> a friend of mine recently was very generous and sent me four used 4CX800 /
> GU74b which he didn?t need anymore.
> 
> The tubes where traveling a while and through several non-EU countries.
> Today the parcel finally arrived.
> 
> I have already heard wild stories about customs, but I didn?t expect this:
> 
> *Customs drilled holes in two tubes and later opened them with a saw.
> 
> I compiled a couple of pictures on my website:
> 
> http://www.dh1tw.de/customs-break-my-tubes-4cx800-gu74b
> 
> Anyone else had already similar experiences?
> 
> *Btw: Is it true that these tubes contain Beryliumoxid and thoriated
> thungsten?
> 
> What is the health risk going out from an opened tube?
> *
> 73 Tobias
> EA4/DH1TW
> *
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps

------------------------------

Message: 2
Date: Thu, 01 Mar 2012 23:02:23 -0700
From: John Lyles <jtml at losalamos.com>
Subject: [Amps] 432 Cavity Amps;  Thomson TH 331
To: amps at contesting.com, Carl <km1h at jeremy.mv.com>
Message-ID: <4F50626F.8010700 at losalamos.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

That sounds like it would be a potent amplifier. What was the looking 
glass program?
Or would you have to shoot me after telling?

Never heard of that tetrode, but I do have a GE industrial catalog of 
loose leaf datasheets. I will check tomorrow. as I'm curious.

If it is a coaxial line circuit, and at 350 MHz, then moving it 80 MHz 
up isn't as bad as the other way. That would kick butt on 432, bounce 
off Mars, etc. and needs big air blowers for certain.
73
John
K5PRO

> Date: Thu, 1 Mar 2012 20:23:28 -0500
> From: "Carl"<km1h at jeremy.mv.com>
> Subject: Re: [Amps] 432 Cavity Amps;  Thomson TH 331
> To:<jtml at vla.com>,    <amps at contesting.com>

> GE made a big tetrode for the USAF Looking Glass program. It was the
> GL-51064, with 2750W PD and rated at 4000W CW output at 400MHz. Its capable
> of 4.2KW input at 1GHz
>
> They were used in a 1000W output AM linear at around 350MHz in a Collins
> 648B-1 which is in a standard airborn slide in rack configuration.
>
> I have 2 of the amps, refurbishd with new tubes, stored and then surplused.
> No power supplies of course.
>
> Id love to get some helping on getting one on 432.
> Tube spec sheets, and Collins schematics are on hand.
>
> The amps date to around 1987 and the tube sheet is dated 11/69 so there must
> be some out there. There is also an ET-T2009 designation on the sheets which
> may be an alternate ID or an internal code. Maybe its an European tube thats
> been rebranded for GE ??
>
> Carl
> KM1H

------------------------------

Message: 3
Date: Thu, 1 Mar 2012 22:40:38 -0800
From: "Jim W7RY" <jimw7ry at gmail.com>
Subject: [Amps] 8877 Amplifier Photos
To: "AMPS" <amps at contesting.com>
Message-ID: <B9CFE85420914E2196D8196C62B3F5DB at Laptop>
Content-Type: text/plain;    charset="iso-8859-1"

I have just posted many more pictures of my homebrew 8877 amplifier on 
Photobucket:

http://s900.photobucket.com/albums/ac206/w7ry/8877%20Amplifier/?start=all

The amp is patterned after the K8RA design that has been in the handbook for a 
number of years. I used a switched tuned input board by WD7S. I also used his 
amplifier control board and his high voltage board as well.

Let me know if you have any comments or questions.  1500 watts + on all bands 
with about 30-40 watts of drive with 4000 volts on the plate.

73
Jim W7RY

------------------------------

Message: 4
Date: Fri, 2 Mar 2012 16:14:54 +0800
From: "Hsu" <hsu4qro at gmail.com>
Subject: Re: [Amps] 8877 Amplifier Photos
To: "Jim W7RY" <jimw7ry at gmail.com>,    "AMPS" <amps at contesting.com>
Message-ID: <0FB49E45E50543DE91B5504B27FD9327 at MICROSOMOFR197>
Content-Type: text/plain; format=flowed; charset="utf-8";
    reply-type=original

It seems use a pot  anda  digtal pannel meter as  counter is that right?
What POT do you use?I 'm designing my big amp what used a 4CX5000R, I
use a long life Plastic Pot( 30 million times) and LCD pannel meter.
   73!Hsu

-----????----- 
From: Jim W7RY
Sent: Friday, March 02, 2012 2:40 PM
To: AMPS
Subject: [Amps] 8877 Amplifier Photos

I have just posted many more pictures of my homebrew 8877 amplifier on 
Photobucket:

http://s900.photobucket.com/albums/ac206/w7ry/8877%20Amplifier/?start=all

The amp is patterned after the K8RA design that has been in the handbook for 
a number of years. I used a switched tuned input board by WD7S. I also used 
his amplifier control board and his high voltage board as well.

Let me know if you have any comments or questions.  1500 watts + on all 
bands with about 30-40 watts of drive with 4000 volts on the plate.

73
Jim W7RY
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps 

------------------------------

Message: 5
Date: Fri, 2 Mar 2012 13:32:34 +0200
From: "Alex Eban" <alexeban at gmail.com>
Subject: Re: [Amps] I always learn something new on eBay
To: <n8de at thepoint.net>,    "'k7fm'" <k7fm at teleport.com>
Cc: amps at contesting.com
Message-ID: <030701ccf868$2fbfadc0$8f3f0940$@com>
Content-Type: text/plain;    charset="us-ascii"

Did you try to breathe them?
Alex    4Z5KS

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of n8de at thepoint.net
Sent: Thursday, March 01, 2012 6:20 PM
To: k7fm
Cc: amps at contesting.com
Subject: Re: [Amps] I always learn something new on eBay

I'd love to see a definition of 'oxygen-free terminals' ...

73
Don
N8DE

Quoting k7fm <k7fm at teleport.com>:

> While shopping on ePay for a pair of spare 805 modulators for my classic
> WWII plate modulated transmitter, I noted a fellow selling teflon sockets,
> complete with oxygen free terminals.  It is claimed that this will improve
> the audio better than a new set of tubes.  I wonder if this improvement
will
> transfer to rf amplifier tube sockets?  Perhaps we can run our linear
> amplfiers Class C and simply buy new sockets.
>
> 73,  Colin  K7FM
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>

_______________________________________________
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Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps

------------------------------

Message: 6
Date: Fri, 2 Mar 2012 06:46:30 -0600
From: Mike Andrews <mikea at mikea.ath.cx>
Subject: Re: [Amps] 432 Cavity Amps;  Thomson TH 331
To: amps at contesting.com
Message-ID: <20120302124630.GF12106 at mikea.ath.cx>
Content-Type: text/plain; charset=us-ascii

On Thu, Mar 01, 2012 at 11:02:23PM -0700, John Lyles wrote:
> That sounds like it would be a potent amplifier. What was the looking 
> glass program?
> Or would you have to shoot me after telling?

"Looking Glass" is an airborne SAC-operated command post to mirror (hence
"Looking Glass") the ground-based SAC command post at Offut AFB. Current
Looking Glass aircraft are Navy E-6B TACAMO ("TAke Command And Move Out")
birds based at Tinker AFB, about 10 miles from me. I see them every day,
and the Lowfer mailing list frequently has reports of TACAMO transmissions
in the 15-30 KHz range.

The TACAMO transmitter is an enormously powerful beast, up in the power
range of your new TH-628 amp, driving a trailing long-wire. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin 

------------------------------

Message: 7
Date: Fri, 02 Mar 2012 07:57:13 -0500
From: Pete Smith N4ZR <n4zr at contesting.com>
Subject: Re: [Amps] What contry customs drilled the holes?
To: amps at contesting.com
Message-ID: <4F50C3A9.70602 at contesting.com>
Content-Type: text/plain; charset=windows-1252; format=flowed

Don't you suppose it probably went like this, wherever it was?

X-ray
"What the heck is that?"
box open
"What the heck are those?"
"Better get inside"
hacksaw and drill
"oops - better box it back up and pretend we never did this."

Could be postal service darn near anywhere.

73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000

On 3/2/2012 12:35 AM, Charles Harpole wrote:
> which nation?
>
> Charles Harpole
> k4vud at hotmail.com
>   >  From: tobias.wellnitz at googlemail.com
>> Date: Thu, 1 Mar 2012 17:48:48 +0100
>> To: amps at contesting.com
>> Subject: [Amps] Customs drilled a hole in my GU74b / 4CX800s
>>
>> Hi,
>>
>> a friend of mine recently was very generous and sent me four used 4CX800 /
>> GU74b which he didn?t need anymore.
>>
>> The tubes where traveling a while and through several non-EU countries.
>> Today the parcel finally arrived.
>>
>> I have already heard wild stories about customs, but I didn?t expect this:
>>
>> *Customs drilled holes in two tubes and later opened them with a saw.
>>
>> I compiled a couple of pictures on my website:
>>
>> http://www.dh1tw.de/customs-break-my-tubes-4cx800-gu74b
>>
>> Anyone else had already similar experiences?
>>
>> *Btw: Is it true that these tubes contain Beryliumoxid and thoriated
>> thungsten?
>>
>> What is the health risk going out from an opened tube?
>> *
>> 73 Tobias
>> EA4/DH1TW
>> *
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>                           
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>

------------------------------

Message: 8
Date: Fri, 2 Mar 2012 06:51:05 -0800
From: "Jim W7RY" <jimw7ry at gmail.com>
Subject: Re: [Amps] 8877 Amplifier Photos
To: "Hsu" <hsu4qro at gmail.com>,    "AMPS" <amps at contesting.com>
Message-ID: <67402A37F1ED4D51BEBDDF07F6332CF3 at Laptop>
Content-Type: text/plain; format=flowed; charset="utf-8";
    reply-type=response

It's just a standard 10 turn 10K ohm linear taper pot. The gears are sized 
is so I have 30 turns available on the vacuum caps.

73
Jim W7RY

--------------------------------------------------
From: "Hsu" <hsu4qro at gmail.com>
Sent: Friday, March 02, 2012 12:14 AM
To: "Jim W7RY" <jimw7ry at gmail.com>; "AMPS" <amps at contesting.com>
Subject: Re: [Amps] 8877 Amplifier Photos

> It seems use a pot  anda  digtal pannel meter as  counter is that right?
> What POT do you use?I 'm designing my big amp what used a 4CX5000R, I
> use a long life Plastic Pot( 30 million times) and LCD pannel meter.
>   73!Hsu
>
> -----????----- 
> From: Jim W7RY
> Sent: Friday, March 02, 2012 2:40 PM
> To: AMPS
> Subject: [Amps] 8877 Amplifier Photos
>
> I have just posted many more pictures of my homebrew 8877 amplifier on 
> Photobucket:
>
> http://s900.photobucket.com/albums/ac206/w7ry/8877%20Amplifier/?start=all
>
> The amp is patterned after the K8RA design that has been in the handbook 
> for a number of years. I used a switched tuned input board by WD7S. I also 
> used his amplifier control board and his high voltage board as well.
>
> Let me know if you have any comments or questions.  1500 watts + on all 
> bands with about 30-40 watts of drive with 4000 volts on the plate.
>
> 73
> Jim W7RY
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps 

------------------------------

Message: 9
Date: Fri, 2 Mar 2012 10:05:20 -0600
From: "Doug Renwick" <ve5ra at sasktel.net>
Subject: [Amps] Amp Supply ATI-6 Tuned Input Boards for sale
To: <amps at contesting.com>, <ham_amplifiers at yahoogroups.com>,
    <rfamplifiers at yahoogroups.com>
Message-ID: <5B6D7A224B0943789554735A76187827 at DOUG5HP>
Content-Type: text/plain;    charset="us-ascii"

I have two Amp Supply ATI 6 Tuned input boards, one new and the other used.

>From the Amp Supply parts list:

Stock # 1235  ATI-6 complete PC board w/6 toroidal coils, 12 trimmer caps, 6
DPDT relays, fully assembled, tuneable 1.8 - 30 MHz, matches any amplifier 6
1/4 x 3 1/4, 12VDC.  89.50

Email me if interested.

Doug

I wasn't born in Saskatchewan, but I got here as soon as I could.

------------------------------

Message: 10
Date: Fri, 2 Mar 2012 11:10:14 -0500
From: "Carl" <km1h at jeremy.mv.com>
Subject: Re: [Amps] 432 Cavity Amps;  Thomson TH 331
To: <jtml at vla.com>,    <amps at contesting.com>
Message-ID: <3D96D7C02C714F1792A5B4825E7F419D at computer1>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
    reply-type=response

Looking Glass was a Boeing EC-135 (modified C-135)developed as a wartime 
command post last resort if all ground based command centers were destroyed.

It mirrored the ground station capability including generating ICBM launch 
commands.The capability also included air to air links with others in the 
fleet.

Many versions were flown for 37 years 24/7 without an accident.
The program was then transferred to the Navy in 1998 using modified 707's as 
the E-6B and is still operational.

There are also 4 USAF E-4B's, converted 747's, which serve as onboard 
command posts for the politicians.

The amps I have were for multi MHz broadband data, video and voice thus the 
low distortion linear mode. At full bore 140cfm of air at 1.9" water are the 
minimum requirement. Not something to be in the same room with.

Filament is a modest 5.7V at 24A and the HV can run up to 7500V for 
"typical" operation. In GG for 2000W at 420 its 5500V at 450ma, and 7500V at 
650ma for 4000W. Drive is 90 and 150W respectively.

Carl
KM1H

----- Original Message ----- 
From: "John Lyles" <jtml at losalamos.com>
To: <amps at contesting.com>; "Carl" <km1h at jeremy.mv.com>
Sent: Friday, March 02, 2012 1:02 AM
Subject: 432 Cavity Amps; Thomson TH 331

> That sounds like it would be a potent amplifier. What was the looking 
> glass program?
> Or would you have to shoot me after telling?
>
> Never heard of that tetrode, but I do have a GE industrial catalog of 
> loose leaf datasheets. I will check tomorrow. as I'm curious.
>
> If it is a coaxial line circuit, and at 350 MHz, then moving it 80 MHz up 
> isn't as bad as the other way. That would kick butt on 432, bounce off 
> Mars, etc. and needs big air blowers for certain.
> 73
> John
> K5PRO
>
>> Date: Thu, 1 Mar 2012 20:23:28 -0500
>> From: "Carl"<km1h at jeremy.mv.com>
>> Subject: Re: [Amps] 432 Cavity Amps;  Thomson TH 331
>> To:<jtml at vla.com>, <amps at contesting.com>
>
>> GE made a big tetrode for the USAF Looking Glass program. It was the
>> GL-51064, with 2750W PD and rated at 4000W CW output at 400MHz. Its 
>> capable
>> of 4.2KW input at 1GHz
>>
>> They were used in a 1000W output AM linear at around 350MHz in a Collins
>> 648B-1 which is in a standard airborn slide in rack configuration.
>>
>> I have 2 of the amps, refurbishd with new tubes, stored and then 
>> surplused.
>> No power supplies of course.
>>
>> Id love to get some helping on getting one on 432.
>> Tube spec sheets, and Collins schematics are on hand.
>>
>> The amps date to around 1987 and the tube sheet is dated 11/69 so there 
>> must
>> be some out there. There is also an ET-T2009 designation on the sheets 
>> which
>> may be an alternate ID or an internal code. Maybe its an European tube 
>> thats
>> been rebranded for GE ??
>>
>> Carl
>> KM1H
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1424 / Virus Database: 2113/4845 - Release Date: 03/01/12
> 

------------------------------

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End of Amps Digest, Vol 111, Issue 4
************************************