Eimac specs say 60 ma per tube absolute max. I see no meaningful increase
over 20-25 ma.
What is the reading into a known 50 Ohm RESISTIVE load?
Id be concerned about the Alpha itself if it allows such a high current.
The 3CPX if anything would want to load to a higher current in a manual
tuned amp but the grid ratings are the same as the regular version..
http://www.g8wrb.org/data/Eimac/3CX800A7.pdf
http://www.g8wrb.org/data/Svetlana/pdf/3CPX800A7.pdf
A soft tube would generally be unable to load to rated grid current and
would tune to maximum output at some nnn level below a full output one.
Carl
KM1H
----- Original Message -----
From: "jsternmd" <jsternmd@earthlink.net>
To: <amps@contesting.com>
Sent: Monday, December 31, 2007 11:26 AM
Subject: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7
>
> What would typical grid current be for an Alpha 87A running 1500w on 20
> or 40m? My 87A gets up to 105 ma (Yellow LED) at times (into a very low
> SWR antenna or dummy load). Is this normal? WOuld the 3CPX800A run
> 1500w at a lower grid current?
>
> 73 de K1JOS (Jerry)
> CCA #11906
> CRA #1777
>
>
>
>
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of amps-request@contesting.com
> Sent: Monday, December 31, 2007 8:37 AM
> To: amps@contesting.com
> Subject: Amps Digest, Vol 60, Issue 45
>
>
> Send Amps mailing list submissions to
> amps@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/amps
> or, via email, send a message with subject or body 'help' to
> amps-request@contesting.com
>
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>
> When replying, please edit your Subject line so it is more specific than
> "Re: Contents of Amps digest..."
>
>
> Today's Topics:
>
> 1. Re: Alpha 87A Tubes (Gary Smith)
> 2. Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ? (DC)
> 3. Re: Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ? (jeremy-ca)
> 4. Re: Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ? (Paul Hewitt)
> 5. Re: [TenTec] Corsair II & Titan 425 (Gary Smith)
> 6. Re: [TenTec] Corsair II & Titan 425 (Gary Smith)
> 7. Re: [TenTec] Corsair II & Titan 425 (Gary Smith)
> 8. Looking for David Kechkaylo (TS711A@aol.com)
> 9. 2x813 or 2x3-500zg ? (Mike Bondarev)
> 10. Re: 2x813 or 2x3-500zg ? (Roger)
> 11. Re: 2x813 or 2x3-500zg ? (jeremy-ca)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 30 Dec 2007 14:08:56 -0800
> From: "Gary Smith" <wa6fgi@sbcglobal.net>
> Subject: Re: [Amps] Alpha 87A Tubes
> To: "Larry P. Greenberg" <wa9mag@ameritech.net>,
> <amps@contesting.com>
> Message-ID: <007e01c84b30$997c1b20$4001a8c0@garys>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> 3CX800A7's are standard (from the factory) in my/their Ameritron
> AL-800H. Never had a minute's problem with them. Runs "legal" all bands
> easily, but I
> do pay attention to the grid current.
> There is a tube the 3CX P 800A7, only diff is they are rated for pulse
> service.
> My .02 on this thread,
> 73's,
> Gary...wa6fgi
>
>
> ------ Original Message -----
> From: "Larry P. Greenberg" <wa9mag@ameritech.net>
> To: <amps@contesting.com>
> Sent: Saturday, December 29, 2007 10:31 AM
> Subject: [Amps] Alpha 87A Tubes
>
>
>>I copied the following from the Alpha website.
>>
>> The Alpha 87A, 89 and 86 were designed to use the YC-238 tube which
>
>> is
>> an Eimac 3CX800A7 that has been screened for low grid current.
> Replacing
>> one or both of the tubes in your amplifier with a regular 3CX800 or
> with a
>> 3CPX800 could lead to unintended problems and consequences which again
> we
>> are not able to cover under warranty.
>>
>> I don't find YC-238 tubes on the Eimac website. While I understand
>> that
>> we may not want to use non Eimac tubes in our amplifiers, I don't
>> understand why replacements cannot be non-matched Eimac 3CX800A7 tubes
>
>> that can be purchased from known wholesale dealers or reputable
> hamfest
>> dealers. I would like to keep spare finals on the shelf but $1,500 a
> pair
>> is really steep.
>>
>> Has anybody used regular 3CX800A7's in their amplifier? Is the YC-238
>> nomenclature an Eimac name or an Alpha name? Does anybody have a
>> specification sheet that they can send me?
>>
>> Larry, WA9MAG
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 30 Dec 2007 17:41:08 -0500
> From: "DC" <daclark56@hotmail.com>
> Subject: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ?
> To: <amps@contesting.com>
> Message-ID: <BLU126-DAV13D200DCC88E663CA32FB9BE570@phx.gbl>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Is the 3CX P 800A7 interchangable with the 3CX800A7?
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 30 Dec 2007 19:20:12 -0500
> From: "jeremy-ca" <km1h@jeremy.mv.com>
> Subject: Re: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ?
> To: "DC" <daclark56@hotmail.com>, <amps@contesting.com>
> Message-ID: <014101c84b42$eaaa8e70$6500a8c0@KITTYMA123>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> All varieties can be considered the same tube for ham use.
> Also any Eimac tube beginning with a Y is automatically 40-100% more
> expensive than its regular production brethren.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "DC" <daclark56@hotmail.com>
> To: <amps@contesting.com>
> Sent: Sunday, December 30, 2007 5:41 PM
> Subject: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ?
>
>
>> Is the 3CX P 800A7 interchangable with the 3CX800A7?
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 30 Dec 2007 16:44:53 -0800
> From: "Paul Hewitt" <wd7s@earthlink.net>
> Subject: Re: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ?
> To: "DC" <daclark56@hotmail.com>, <amps@contesting.com>
> Message-ID: <002801c84b46$5d0e95d0$9539f604@qroproductions>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Yes and no. The CPX version is rated for a higher plate voltage than
> the CX
> version with the Eimac tube. The CPX tube has a taller ceramic
> insulating
> portion at the base. The Svetlana CPX and CX versions had the same
> ceramic
> height and both will take the higher plate voltage.
> 73, Paul
>
> PAUL HEWITT
> WD7S PRODUCTIONS
> QRO HOMEBREW COMPONENTS
> http://home.earthlink.net/~wd7s
>
>
>
> ----- Original Message -----
> From: "DC" <daclark56@hotmail.com>
> To: <amps@contesting.com>
> Sent: Sunday, December 30, 2007 2:41 PM
> Subject: [Amps] Alpha 87A Tubes 3CX800A7 and the 3CX P 800A7 ?
>
>
>> Is the 3CX P 800A7 interchangable with the 3CX800A7?
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sun, 30 Dec 2007 20:51:28 -0500
> From: "Gary Smith" <Gary@doctorgary.net>
> Subject: Re: [Amps] [TenTec] Corsair II & Titan 425
> To: Amps@contesting.com
> Message-ID: <477804D0.5692.12D1044@Gary.doctorgary.net>
> Content-Type: text/plain; charset=US-ASCII
>
> Hi Carl,
>
> I've tried that and the amp keys but it does not seem to key the
> Corsair. I can see where there's a slight dip in voltage and a show
> of some grid current to the 425 when I key but the key out from the
> 425 into the key in of the corsair does not trigger the corsair.
>
> If I run the key in to the corsair via the same RCA jack, the corsair
> transmits just fine.
>
> So key the amp? yes but the amp key the corsair? No.
>
> Ideas?
>
> Thanks!
>
> Gary
>
>> No. QSK and Ext T/R are very different. The corsair never had the
>> TXOut and TXEn lines on it, which are required for a QSK amp. What
>> you are supposed to do is connect Ext T/R to the amplifier keying
>> line. This will not give you QSK but it will work with the amp that
>> way.
>>
>> Another completely different approach is to connect your keyer output
>> directly to where TXOut would have been connected to the amp. Then
>> connect the output keying line of the amp to key the corsair. This
>> will give you QSK and guarantee that the amp keys before the corsair
>> transmits.
>>
>> Carl Moreschi N4PY
>> 121 Little Bell Drive
>> Bell Mountain
>> Hays, NC 28635
>> ----- Original Message -----
>> From: "Gary Smith" <Gary@doctorgary.net>
>> To: <tentec@contesting.com>
>> Sent: Sunday, December 30, 2007 7:37 PM
>> Subject: [TenTec] Corsair II & Titan 425
>>
>>
>> > Am sending the Omni V to TenTec for allignment. Not sure of the best
>
>> > way to connect my back up rig (Corsair II) to the amp for QSK.
>> >
>> > With the Omni V I connected the TX out & TX en to their counterparts
>
>> > on the 425. I see no TX out or TX en on the Corsair but there exists
>
>> > QSK and EXT T/R connectors on the Corsair. Are these the same
>> > function but different names? I do want to use QSK.
>> >
>> > Thanks,
>> >
>> > Gary
>> > KA1J
>> > _______________________________________________
>> > TenTec mailing list
>> > TenTec@contesting.com
>> > http://lists.contesting.com/mailman/listinfo/tentec
>>
>>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sun, 30 Dec 2007 21:01:52 -0500
> From: "Gary Smith" <Gary@doctorgary.net>
> Subject: Re: [Amps] [TenTec] Corsair II & Titan 425
> To: Amps@contesting.com
> Message-ID: <47780740.29591.13692D6@Gary.doctorgary.net>
> Content-Type: text/plain; charset=US-ASCII
>
> Carl, somehow related to the keyer & the 425...
>
> If I run a straight key into the 425 as you suggested, it works fine
> and the amp & Corsair both fire.
>
> By the keyer alone it triggers the 425 but the 425 does not trigger
> the Corsair.
>
> Interesting.
>
> Gary
>
>> Hi Carl,
>>
>> I've tried that and the amp keys but it does not seem to key the
>> Corsair. I can see where there's a slight dip in voltage and a show of
>
>> some grid current to the 425 when I key but the key out from the 425
>> into the key in of the corsair does not trigger the corsair.
>>
>> If I run the key in to the corsair via the same RCA jack, the corsair
>> transmits just fine.
>>
>> So key the amp? yes but the amp key the corsair? No.
>>
>> Ideas?
>>
>> Thanks!
>>
>> Gary
>>
>> > No. QSK and Ext T/R are very different. The corsair never had the
>>
>> > TXOut and TXEn lines on it, which are required for a QSK amp. What
>>
>> > you are supposed to do is connect Ext T/R to the amplifier keying
>> > line. This will not give you QSK but it will work with the amp
>> that
>> > way.
>> >
>> > Another completely different approach is to connect your keyer
>> output
>> > directly to where TXOut would have been connected to the amp. Then
>>
>> > connect the output keying line of the amp to key the corsair. This
>>
>> > will give you QSK and guarantee that the amp keys before the
>> corsair
>> > transmits.
>> >
>> > Carl Moreschi N4PY
>> > 121 Little Bell Drive
>> > Bell Mountain
>> > Hays, NC 28635
>> > ----- Original Message -----
>> > From: "Gary Smith" <Gary@doctorgary.net>
>> > To: <tentec@contesting.com>
>> > Sent: Sunday, December 30, 2007 7:37 PM
>> > Subject: [TenTec] Corsair II & Titan 425
>> >
>> >
>> > > Am sending the Omni V to TenTec for allignment. Not sure of the
>> best
>> > > way to connect my back up rig (Corsair II) to the amp for QSK.
>> > >
>> > > With the Omni V I connected the TX out & TX en to their
>> counterparts
>> > > on the 425. I see no TX out or TX en on the Corsair but there
>> exists
>> > > QSK and EXT T/R connectors on the Corsair. Are these the same
>> > > function but different names? I do want to use QSK.
>> > >
>> > > Thanks,
>> > >
>> > > Gary
>> > > KA1J
>> > > _______________________________________________
>> > > TenTec mailing list
>> > > TenTec@contesting.com
>> > > http://lists.contesting.com/mailman/listinfo/tentec
>> >
>> >
>>
>>
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sun, 30 Dec 2007 21:11:51 -0500
> From: "Gary Smith" <Gary@doctorgary.net>
> Subject: Re: [Amps] [TenTec] Corsair II & Titan 425
> To: Amps@contesting.com
> Message-ID: <47780997.4618.13FB825@Gary.doctorgary.net>
> Content-Type: text/plain; charset=US-ASCII
>
> Ah rats,
>
> Cross post. Sorry
>
> Gary
> KA1J
>
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 31 Dec 2007 01:07:47 EST
> From: TS711A@aol.com
> Subject: [Amps] Looking for David Kechkaylo
> To: Amps@contesting.com
> Message-ID: <d01.205cf240.34a9e133@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Hello, does anyone have an email for David Kechkaylo? He worked at
> Heathkit
> at one time and has lots of good info. I only find old posts from him
> online.
> Thanks !!
>
>
>
> **************************************See AOL's top rated recipes
> (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)
>
>
> ------------------------------
>
> Message: 9
> Date: Mon, 31 Dec 2007 10:42:34 +0300
> From: Mike Bondarev <mikebond@mosfirm.ru>
> Subject: [Amps] 2x813 or 2x3-500zg ?
> To: Amps@contesting.com
> Message-ID: <1494475189.20071231104234@mosfirm.ru>
> Content-Type: text/plain; charset=us-ascii
>
> Hello to everybody! Happy New Year 2008!
> In the coming year I would like to build an amplifier for "everyday
> use". For the contesting I already made the amplifier with GU-84B and
> GM3SEK's tetrode boards and it work fantastic! The second amp I would
> like to make with glass tubes. What you guys can recommend me? I was
> thinking about two 813 in grounded grid configurations but now I'm
> thinking why not the pair of 3-500zg from RF-parts? I newer used 3-500zg
> before so I can't compare it to 813. I understand the difference in
> pricing but I also know it's easy to buy matched set of 3-500zg but it's
> just impossible to find matched pair of 813.
>
> Regards, Mike RL3BM
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> ------------------------------
>
> Message: 10
> Date: Mon, 31 Dec 2007 03:32:29 -0500
> From: "Roger" <sub1@rogerhalstead.com>
> Subject: Re: [Amps] 2x813 or 2x3-500zg ?
> To: <Amps@contesting.com>
> Message-ID: <000401c84b87$aea7cd80$6600a8c0@shop32>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> My personal opinions:
>
> The 813 is a nice tube and I have built amps using them. However the
> 3-500Z is a current tube, in production, and not outlandishly
> priced.
> As far as as a matched pair, I've never worried about that with 3-500s
> unless they are way off and I've not found any that were. The 3-500s
> are
> not a higain tube, but if you have an honest 100 watts and enough plate
> voltage they'll run the legal limit.
>
> Roger (K8RI)
>
>
>
>
>> Hello to everybody! Happy New Year 2008!
>> In the coming year I would like to build an amplifier for "everyday
>> use". For the contesting I already made the amplifier with GU-84B and
>> GM3SEK's tetrode boards and it work fantastic! The second amp I would
>
>> like to make with glass tubes. What you guys can recommend me? I was
>> thinking about two 813 in grounded grid configurations but now I'm
>> thinking why not the pair of 3-500zg from RF-parts? I newer used
>> 3-500zg before so I can't compare it to 813. I understand the
>> difference in pricing but I also know it's easy to buy matched set of
>> 3-500zg but it's just impossible to find matched pair of 813.
>>
>> Regards, Mike RL3BM
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 11
> Date: Mon, 31 Dec 2007 08:36:44 -0500
> From: "jeremy-ca" <km1h@jeremy.mv.com>
> Subject: Re: [Amps] 2x813 or 2x3-500zg ?
> To: "Mike Bondarev" <mikebond@mosfirm.ru>, <Amps@contesting.com>
> Message-ID: <002501c84bb2$313e7da0$6500a8c0@KITTYMA123>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> The 813 is almost a 70 year old design yet it is still one of the best
> tubes
> ever made.
>
> Brand new US military surplus ones are on Ebay on a regular basis and at
>
> very low prices. No matching is required. I recently bought 4 813's and
> sockets off Ebay for around $80 for all. These are for an AM amplifier.
>
> In GG service the 813 IMD is in the -33dB range according to published
> info
> making it a very clean performer.
>
> My regular SSB/CW HF amp uses 3-500Z's and they are also an excellent
> tube.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Mike Bondarev" <mikebond@mosfirm.ru>
> To: <Amps@contesting.com>
> Sent: Monday, December 31, 2007 2:42 AM
> Subject: [Amps] 2x813 or 2x3-500zg ?
>
>
>> Hello to everybody! Happy New Year 2008!
>> In the coming year I would like to build an amplifier for "everyday
>> use". For the contesting I already made the amplifier with GU-84B and
>> GM3SEK's tetrode boards and it work fantastic! The second amp I would
>
>> like to make with glass tubes. What you guys can recommend me? I was
>> thinking about two 813 in grounded grid configurations but now I'm
>> thinking why not the pair of 3-500zg from RF-parts? I newer used
>> 3-500zg before so I can't compare it to 813. I understand the
>> difference in pricing but I also know it's easy to buy matched set of
>> 3-500zg but it's just impossible to find matched pair of 813.
>>
>> Regards, Mike RL3BM
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>>
>
>
>
> ------------------------------
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>
>
> End of Amps Digest, Vol 60, Issue 45
> ************************************
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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