From swanman at cfu.net  Sat Mar 21 10:38:23 2015
From: swanman at cfu.net (Jan C. Robbins)
Date: Sat, 21 Mar 2015 09:38:23 -0500
Subject: [ETO_Alpha] WTB: Mint Alpha 87A or 87A Omega
Message-ID: <550D825F.8050703@cfu.net>

After I sold my Alpha 87A an elderly (meaning older than me!) friend 
said he wished he'd spoken for it. I told him I'd try to find him one. 
So I am looking for a late Alpha 87A or 87A Omega, in excellent cosmetic 
and working condition, with full output, AlphaMax and AlphaRemote. If 
you have one for sale please email details, with photo. I do PayPal as 
well as other methods, and I'm good on QTH.COM. Many tks, es 73! Jan N0JR

From NZ3O at arrl.net  Sun Mar 22 16:23:58 2015
From: NZ3O at arrl.net (Byron Peebles)
Date: Sun, 22 Mar 2015 16:23:58 -0400
Subject: [ETO_Alpha] FORSALE: Alpha 9500 Amplifier
Message-ID: <550F24DE.1020602@arrl.net>

I am offering for sale a pristine Alpha 9500 amplifier.
Non-smoking, low mileage, casual operation.
In my situation I can rarely use the full output, so I'm moving down 
from full legal limit.

73, Byron

NZ3O over at ARRL's dot NET


From swanman at cfu.net  Mon Mar 23 09:32:10 2015
From: swanman at cfu.net (Jan C. Robbins)
Date: Mon, 23 Mar 2015 08:32:10 -0500
Subject: [ETO_Alpha] FS:  New unopened 3CPX800A7
Message-ID: <551015DA.4060600@cfu.net>

If you're running a 9500, here is your chance to get that extra tube at 
a REASONABLE price.

I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 
(8877), capable of handling much higher plate current than the standard 
Eimac or Penta 8877 you buy from, e.g., RF Concepts, Ameritron or RF 
Parts (all of which sell Pentas, which are superb tubes). I sold 3CPXs 
to hams for nearly 20 years, and they are THE BEST tubes for 
very-high-power amps.  The 3CPX1500 normally sell for $775 and up (way 
up), but I can ship this one anywhere lower 48, fully insured, for $595. 
PayPal preferred, other methods acceptable. Tks es 73 N0JR



From 4cx250b at miamioh.edu  Mon Mar 23 11:55:30 2015
From: 4cx250b at miamioh.edu (MU 4CX250B)
Date: Mon, 23 Mar 2015 09:55:30 -0600
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <551015DA.4060600@cfu.net>
References: <551015DA.4060600@cfu.net>
Message-ID: <-5234212768510755297@unknownmsgid>

I was under the impression that the pulse rated tubes were identical
internally to the non-pulse-rated  tubes, except for slightly longer
ceramic insulation that increased the peak voltage rating (and added
more inductance to the internal grid wires.) I know the tubes are
specified for high peak currents, but i thought that was just an
additional specification, not a change in tube construction. If I'm
mistaken, I would welcome being corrected.
73,
Jim w8zr

Sent from my iPhone

> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>
> If you're running a 9500, here is your chance to get that extra tube at a REASONABLE price.
>
> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 (8877), capable of handling much higher plate current than the standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, Ameritron or RF Parts (all of which sell Pentas, which are superb tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE BEST tubes for very-high-power amps.  The 3CPX1500 normally sell for $775 and up (way up), but I can ship this one anywhere lower 48, fully insured, for $595. PayPal preferred, other methods acceptable. Tks es 73 N0JR
>
>
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ETO_Alpha at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

From 4cx250b at miamioh.edu  Mon Mar 23 13:00:37 2015
From: 4cx250b at miamioh.edu (Jim Garland)
Date: Mon, 23 Mar 2015 11:00:37 -0600
Subject: [ETO_Alpha] FW:  FS: New unopened 3CPX800A7
In-Reply-To: <038501d0658a$a6dedce0$f49c96a0$@miamioh.edu>
References: <551015DA.4060600@cfu.net> <-5234212768510755297@unknownmsgid>
	<55103963.9060308@cfu.net>
	<038501d0658a$a6dedce0$f49c96a0$@miamioh.edu>
Message-ID: <039501d0658a$e362ce60$aa286b20$@miamioh.edu>

Jan,

Tnx for your info, but I'm curious where you found the data showing the d.c. plate current rating is 25-30%  than the 1A rating for a non-pulse tube. I realize the pulse-rated tubes are rated at 5.5V filament voltage, and while that might be a way to inrease cathode emission (and higher plate current), doing so significantly shortens tube life. The 3cpx1500a7 data sheet recommends backing off the filament voltage to 5.0V to inrease tube life. That suggests the filaments of the pulse-rated and non-pulse rated tubes are the same, with identical cathode construction..

 

BTW, an ordinary 8877 run at its maximum ratings of 4 kV plate and 1A plate current will routinely produce about 2500W of RF power. I have Eimac 8877s that are decades old in my homebrew amps that still show full power output. I've had some unfortunate experience in the past two years with Chinese made 8877s, however. Two of the ones I've used have died after a hundred hours or so because of internal arcing.

73,

Jim W8ZR

 

From: Jan C. Robbins [mailto:swanman at cfu.net] 
Sent: Monday, March 23, 2015 10:04 AM
To: MU 4CX250B
Subject: Re: [ETO_Alpha] FS: New unopened 3CPX800A7

 

The key difference is that the pulse-rated tubes are built to withstand plate current 25-30% higher than non-pulse--that's why they're used in medical amps, radar, and FM transmitters.  So if you are an avid contester, esp. on CW and rtty, the pulse tube is to be preferred, esp. also if you tend to run power in excess of about 1300w.  The physical difference in the tubes is about 1/4" in height, which doesn't matter, but the durability difference is substantial, and it does matter: pulse tubes last longer.  

When I was still selling tubes, many customers were international contesters, who really value the pulse difference.  For normal SSB operation or casual DXing, there is no meaningful difference, but a pulse 8877 at $595 is still a very good buy.  (Of course, the grid current requirements are just the same, pulse or no pulse.)

Tks inquiry!  73 Jan

On 3/23/2015 10:55 AM, MU 4CX250B wrote:

I was under the impression that the pulse rated tubes were identical
internally to the non-pulse-rated  tubes, except for slightly longer
ceramic insulation that increased the peak voltage rating (and added
more inductance to the internal grid wires.) I know the tubes are
specified for high peak currents, but i thought that was just an
additional specification, not a change in tube construction. If I'm
mistaken, I would welcome being corrected.
73,
Jim w8zr
 
Sent from my iPhone
 

On Mar 23, 2015, at 7:32 AM, Jan C. Robbins  <mailto:swanman at cfu.net> <swanman at cfu.net> wrote:
 
If you're running a 9500, here is your chance to get that extra tube at a REASONABLE price.
 
I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 (8877), capable of handling much higher plate current than the standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, Ameritron or RF Parts (all of which sell Pentas, which are superb tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE BEST tubes for very-high-power amps.  The 3CPX1500 normally sell for $775 and up (way up), but I can ship this one anywhere lower 48, fully insured, for $595. PayPal preferred, other methods acceptable. Tks es 73 N0JR
 
 
______________________________________________________________
ETO_Alpha mailing list
Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:ETO_Alpha at mailman.qth.net
 
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Please help support this email list: http://www.qsl.net/donate.html

 


From swanman at cfu.net  Mon Mar 23 14:50:10 2015
From: swanman at cfu.net (Jan C. Robbins)
Date: Mon, 23 Mar 2015 13:50:10 -0500
Subject: [ETO_Alpha] 3CPX1500A7 Sold - Thanks to all who replied!
Message-ID: <55106062.1000800@cfu.net>

Many tks to all seious buyers!  Gud DX es 73


From w5mc at austin.rr.com  Mon Mar 23 16:51:07 2015
From: w5mc at austin.rr.com (Mac McCullough)
Date: Mon, 23 Mar 2015 15:51:07 -0500
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <-5234212768510755297@unknownmsgid>
References: <551015DA.4060600@cfu.net> <-5234212768510755297@unknownmsgid>
Message-ID: <55107CBB.20005@austin.rr.com>

At the first reading I also noticed what Jan had said about higher 
CURRENT  values for the tube,  but i dismissed it as his push to get 
something listed and not to hopefully overstated the value or features 
of the CPX tube..

Beginning in May of last year I went on a  "update" of my Alpha 77Sx  
Soon like most things, the project went big or more. Followed by a new 
HV filter cap and a slight increase in capacitance as well operating 
voltage. Then came the main Xformer followed by a new HV rectifier board 
that has been totally redesigned and updated. All the while the moment 
of effort and truth was fast approaching.

I was yellow, and punted to Eimac for help.  In two separate calls with 
direct application engineers for the 8877/3CX1500A-7 tube they never 
budged on the HV top rating of 5000 vdc.. My amp was now making 4950 
idle plate voltage, yes sure they tested it higher, but would not move 
even for idle voltage. Finally we discussed real operating conditions 
and characteristics of the amp proper. This is a conversation in it's 
own self.

As an off hand comment it was proffered, had i considered the 3CPX 
version of the 3CX tube  I said no never heard of it.  Soon enough as 
much data as they would release was here on my computer for review. Yes 
the outward tube design for the CPX gives the white ceramic area about a 
3/16-1/4" taller profile than the 8877/3CX model.  Outwardly that is it. 
No more.
I was struggling within myself about and even though it was at idle the 
higher right at 5Kv voltage where before the amp had run like 3.8Kv at 
idle, looking at the Plate meter "pegged" or very damn near left me no 
room for comfort and seriously questioning my effort and how i had lost 
the original objective and was now lost in the forest of higher Plate 
Voltage..

I like the 77Sx  and was just not warming to the idea of the 8877 and 
5kv and operating right at or on the edge..

The operating and performance spec's for the CPX tube had immediate 
appeal and the 10kv plate voltage spec I was in love with and as Jim 
states it was only for the HIGHER plate VOLTAGE pulse and as it was 
explained to me indeed only the Ceramic body length was increased to 
allow for a slightly higher grid inductance and plate voltage.
I bought into the CPX version and went on the hunt for a pair of the 
damn things.  Soon enough that was accomplished and at what I thought 
was a decent enough price of $375 per tube and while not new did come 
from a medical application and checked almost identical to new tube 
testing numbers.
As for operation is was text book if not easier and quicker in the 
Loading and Tuning to get the amp up and performing, an absolute breeze, 
I had total confidence from the outset and that was not misplaced. I 
have had the 77 since it was new in 85' . It has always loaded and tuned 
well, but now the SWEET spots are or seem very sure and easy to walk 
into and rock back and forth between tune and load and just feel and 
know you are at the best efficiency of all the design parameters ...

Soon after I had the thought of spare tubes and that i wanted a set,  
none were showing up in the usual haunts, only ebay, United RF seems to 
have as I recall at the time 56 of the CPX tubes listed.  I wanted the 
personal attention and knowledge of the tube so i called and soon enough 
we had agreed on $380.00 per tube incl shipping and test results, so i 
have a set of spare tubes now as well..

closing notes:  my 77 had the original Eimac 8877 tubes as supplied when 
delivered new and had become weak and not holding the same numbers of 
recorded settings i have recorded for various band freq and antennas SWR 
points .. so that is what started the whole circus and $2,400 later not 
including the spare set of tubes.  If the amp last me the rest of my 
operating life, that i have over invested in the amp will be of small 
concern, reflecting back to 85'  i had to hock my ass to buy the thing 
in the first place.

Final thought:  I like using the CPX version tube and i don't drive the 
amp any more or harder than i previously did..

The fellow who is offering the replacement HV boards did a splendid job 
and that was the second 'goal' to replace or just assure the performance 
of the HV rectifier board. over time i had already replaced and upgraded 
the other smaller ckt boards.

HV board: John Stanford, email is wb8svn at gmail.com
Xformer:   Hammond using the Peter Dahl design  using DigiKey
HV Filter Cap:   Condenser Products
other small nuances and tricks i had to use upon request

Warm regards:  mac/mc  w5mc

On 3/23/2015 10:55 AM, MU 4CX250B wrote:
> I was under the impression that the pulse rated tubes were identical
> internally to the non-pulse-rated  tubes, except for slightly longer
> ceramic insulation that increased the peak voltage rating (and added
> more inductance to the internal grid wires.) I know the tubes are
> specified for high peak currents, but i thought that was just an
> additional specification, not a change in tube construction. If I'm
> mistaken, I would welcome being corrected.
> 73,
> Jim w8zr
>
> Sent from my iPhone
>
>> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>>
>> If you're running a 9500, here is your chance to get that extra tube at a REASONABLE price.
>>
>> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 (8877), capable of handling much higher plate current than the standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, Ameritron or RF Parts (all of which sell Pentas, which are superb tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE BEST tubes for very-high-power amps.  The 3CPX1500 normally sell for $775 and up (way up), but I can ship this one anywhere lower 48, fully insured, for $595. PayPal preferred, other methods acceptable. Tks es 73 N0JR
>>
>>
>> ______________________________________________________________
>> ETO_Alpha mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ETO_Alpha at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ETO_Alpha at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>


From w5mc at austin.rr.com  Mon Mar 23 16:55:35 2015
From: w5mc at austin.rr.com (Mac McCullough)
Date: Mon, 23 Mar 2015 15:55:35 -0500
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <55107CBB.20005@austin.rr.com>
References: <551015DA.4060600@cfu.net> <-5234212768510755297@unknownmsgid>
	<55107CBB.20005@austin.rr.com>
Message-ID: <55107DC7.9010601@austin.rr.com>

WE ARE talking here about the 3CPX1500A-7 tube  and NOT the 3cpx800a7  
.. sri didn't catch what tube number Jim had listed,  i was keying off 
what i had seen as Jan's listing for the 3CPX1500 tube

On 3/23/2015 3:51 PM, Mac McCullough wrote:
> At the first reading I also noticed what Jan had said about higher 
> CURRENT  values for the tube,  but i dismissed it as his push to get 
> something listed and not to hopefully overstated the value or features 
> of the CPX tube..
>
> Beginning in May of last year I went on a  "update" of my Alpha 77Sx  
> Soon like most things, the project went big or more. Followed by a new 
> HV filter cap and a slight increase in capacitance as well operating 
> voltage. Then came the main Xformer followed by a new HV rectifier 
> board that has been totally redesigned and updated. All the while the 
> moment of effort and truth was fast approaching.
>
> I was yellow, and punted to Eimac for help.  In two separate calls 
> with direct application engineers for the 8877/3CX1500A-7 tube they 
> never budged on the HV top rating of 5000 vdc.. My amp was now making 
> 4950 idle plate voltage, yes sure they tested it higher, but would not 
> move even for idle voltage. Finally we discussed real operating 
> conditions and characteristics of the amp proper. This is a 
> conversation in it's own self.
>
> As an off hand comment it was proffered, had i considered the 3CPX 
> version of the 3CX tube  I said no never heard of it.  Soon enough as 
> much data as they would release was here on my computer for review. 
> Yes the outward tube design for the CPX gives the white ceramic area 
> about a 3/16-1/4" taller profile than the 8877/3CX model.  Outwardly 
> that is it. No more.
> I was struggling within myself about and even though it was at idle 
> the higher right at 5Kv voltage where before the amp had run like 
> 3.8Kv at idle, looking at the Plate meter "pegged" or very damn near 
> left me no room for comfort and seriously questioning my effort and 
> how i had lost the original objective and was now lost in the forest 
> of higher Plate Voltage..
>
> I like the 77Sx  and was just not warming to the idea of the 8877 and 
> 5kv and operating right at or on the edge..
>
> The operating and performance spec's for the CPX tube had immediate 
> appeal and the 10kv plate voltage spec I was in love with and as Jim 
> states it was only for the HIGHER plate VOLTAGE pulse and as it was 
> explained to me indeed only the Ceramic body length was increased to 
> allow for a slightly higher grid inductance and plate voltage.
> I bought into the CPX version and went on the hunt for a pair of the 
> damn things.  Soon enough that was accomplished and at what I thought 
> was a decent enough price of $375 per tube and while not new did come 
> from a medical application and checked almost identical to new tube 
> testing numbers.
> As for operation is was text book if not easier and quicker in the 
> Loading and Tuning to get the amp up and performing, an absolute 
> breeze, I had total confidence from the outset and that was not 
> misplaced. I have had the 77 since it was new in 85' . It has always 
> loaded and tuned well, but now the SWEET spots are or seem very sure 
> and easy to walk into and rock back and forth between tune and load 
> and just feel and know you are at the best efficiency of all the 
> design parameters ...
>
> Soon after I had the thought of spare tubes and that i wanted a set,  
> none were showing up in the usual haunts, only ebay, United RF seems 
> to have as I recall at the time 56 of the CPX tubes listed.  I wanted 
> the personal attention and knowledge of the tube so i called and soon 
> enough we had agreed on $380.00 per tube incl shipping and test 
> results, so i have a set of spare tubes now as well..
>
> closing notes:  my 77 had the original Eimac 8877 tubes as supplied 
> when delivered new and had become weak and not holding the same 
> numbers of recorded settings i have recorded for various band freq and 
> antennas SWR points .. so that is what started the whole circus and 
> $2,400 later not including the spare set of tubes.  If the amp last me 
> the rest of my operating life, that i have over invested in the amp 
> will be of small concern, reflecting back to 85'  i had to hock my ass 
> to buy the thing in the first place.
>
> Final thought:  I like using the CPX version tube and i don't drive 
> the amp any more or harder than i previously did..
>
> The fellow who is offering the replacement HV boards did a splendid 
> job and that was the second 'goal' to replace or just assure the 
> performance of the HV rectifier board. over time i had already 
> replaced and upgraded the other smaller ckt boards.
>
> HV board: John Stanford, email is wb8svn at gmail.com
> Xformer:   Hammond using the Peter Dahl design  using DigiKey
> HV Filter Cap:   Condenser Products
> other small nuances and tricks i had to use upon request
>
> Warm regards:  mac/mc  w5mc
>
> On 3/23/2015 10:55 AM, MU 4CX250B wrote:
>> I was under the impression that the pulse rated tubes were identical
>> internally to the non-pulse-rated  tubes, except for slightly longer
>> ceramic insulation that increased the peak voltage rating (and added
>> more inductance to the internal grid wires.) I know the tubes are
>> specified for high peak currents, but i thought that was just an
>> additional specification, not a change in tube construction. If I'm
>> mistaken, I would welcome being corrected.
>> 73,
>> Jim w8zr
>>
>> Sent from my iPhone
>>
>>> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>>>
>>> If you're running a 9500, here is your chance to get that extra tube 
>>> at a REASONABLE price.
>>>
>>> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 
>>> (8877), capable of handling much higher plate current than the 
>>> standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, 
>>> Ameritron or RF Parts (all of which sell Pentas, which are superb 
>>> tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE 
>>> BEST tubes for very-high-power amps.  The 3CPX1500 normally sell for 
>>> $775 and up (way up), but I can ship this one anywhere lower 48, 
>>> fully insured, for $595. PayPal preferred, other methods acceptable. 
>>> Tks es 73 N0JR
>>>
>>>
>>> ______________________________________________________________
>>> ETO_Alpha mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>> ______________________________________________________________
>> ETO_Alpha mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ETO_Alpha at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ETO_Alpha at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>


From swanman at cfu.net  Mon Mar 23 16:59:54 2015
From: swanman at cfu.net (Jan C. Robbins)
Date: Mon, 23 Mar 2015 15:59:54 -0500
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <55107DC7.9010601@austin.rr.com>
References: <551015DA.4060600@cfu.net>
	<-5234212768510755297@unknownmsgid>	<55107CBB.20005@austin.rr.com>
	<55107DC7.9010601@austin.rr.com>
Message-ID: <55107ECA.2080702@cfu.net>

About 100 of the top contesters in the world bought 3CPX1500s from me, 
and a bunch more the 3CPX800s.   So far as I know, they're all still 
using those tubes, some of them 20 years later. Obviously, none of them 
knew what they were doing, eh Mac? Just why, I wonder, do some people 
think engineers designed DIFFERENT tubes for medical, pulse and radar 
use if the 3CX versions did the same thing. Interesting.

73 to all, and thanks again for the legitimate inquiries.  Jan

On 3/23/2015 3:55 PM, Mac McCullough wrote:
> WE ARE talking here about the 3CPX1500A-7 tube  and NOT the 3cpx800a7  
> .. sri didn't catch what tube number Jim had listed,  i was keying off 
> what i had seen as Jan's listing for the 3CPX1500 tube
>
> On 3/23/2015 3:51 PM, Mac McCullough wrote:
>> At the first reading I also noticed what Jan had said about higher 
>> CURRENT  values for the tube,  but i dismissed it as his push to get 
>> something listed and not to hopefully overstated the value or 
>> features of the CPX tube..
>>
>> Beginning in May of last year I went on a  "update" of my Alpha 77Sx  
>> Soon like most things, the project went big or more. Followed by a 
>> new HV filter cap and a slight increase in capacitance as well 
>> operating voltage. Then came the main Xformer followed by a new HV 
>> rectifier board that has been totally redesigned and updated. All the 
>> while the moment of effort and truth was fast approaching.
>>
>> I was yellow, and punted to Eimac for help.  In two separate calls 
>> with direct application engineers for the 8877/3CX1500A-7 tube they 
>> never budged on the HV top rating of 5000 vdc.. My amp was now making 
>> 4950 idle plate voltage, yes sure they tested it higher, but would 
>> not move even for idle voltage. Finally we discussed real operating 
>> conditions and characteristics of the amp proper. This is a 
>> conversation in it's own self.
>>
>> As an off hand comment it was proffered, had i considered the 3CPX 
>> version of the 3CX tube  I said no never heard of it.  Soon enough as 
>> much data as they would release was here on my computer for review. 
>> Yes the outward tube design for the CPX gives the white ceramic area 
>> about a 3/16-1/4" taller profile than the 8877/3CX model.  Outwardly 
>> that is it. No more.
>> I was struggling within myself about and even though it was at idle 
>> the higher right at 5Kv voltage where before the amp had run like 
>> 3.8Kv at idle, looking at the Plate meter "pegged" or very damn near 
>> left me no room for comfort and seriously questioning my effort and 
>> how i had lost the original objective and was now lost in the forest 
>> of higher Plate Voltage..
>>
>> I like the 77Sx  and was just not warming to the idea of the 8877 and 
>> 5kv and operating right at or on the edge..
>>
>> The operating and performance spec's for the CPX tube had immediate 
>> appeal and the 10kv plate voltage spec I was in love with and as Jim 
>> states it was only for the HIGHER plate VOLTAGE pulse and as it was 
>> explained to me indeed only the Ceramic body length was increased to 
>> allow for a slightly higher grid inductance and plate voltage.
>> I bought into the CPX version and went on the hunt for a pair of the 
>> damn things.  Soon enough that was accomplished and at what I thought 
>> was a decent enough price of $375 per tube and while not new did come 
>> from a medical application and checked almost identical to new tube 
>> testing numbers.
>> As for operation is was text book if not easier and quicker in the 
>> Loading and Tuning to get the amp up and performing, an absolute 
>> breeze, I had total confidence from the outset and that was not 
>> misplaced. I have had the 77 since it was new in 85' . It has always 
>> loaded and tuned well, but now the SWEET spots are or seem very sure 
>> and easy to walk into and rock back and forth between tune and load 
>> and just feel and know you are at the best efficiency of all the 
>> design parameters ...
>>
>> Soon after I had the thought of spare tubes and that i wanted a set,  
>> none were showing up in the usual haunts, only ebay, United RF seems 
>> to have as I recall at the time 56 of the CPX tubes listed.  I wanted 
>> the personal attention and knowledge of the tube so i called and soon 
>> enough we had agreed on $380.00 per tube incl shipping and test 
>> results, so i have a set of spare tubes now as well..
>>
>> closing notes:  my 77 had the original Eimac 8877 tubes as supplied 
>> when delivered new and had become weak and not holding the same 
>> numbers of recorded settings i have recorded for various band freq 
>> and antennas SWR points .. so that is what started the whole circus 
>> and $2,400 later not including the spare set of tubes.  If the amp 
>> last me the rest of my operating life, that i have over invested in 
>> the amp will be of small concern, reflecting back to 85'  i had to 
>> hock my ass to buy the thing in the first place.
>>
>> Final thought:  I like using the CPX version tube and i don't drive 
>> the amp any more or harder than i previously did..
>>
>> The fellow who is offering the replacement HV boards did a splendid 
>> job and that was the second 'goal' to replace or just assure the 
>> performance of the HV rectifier board. over time i had already 
>> replaced and upgraded the other smaller ckt boards.
>>
>> HV board: John Stanford, email is wb8svn at gmail.com
>> Xformer:   Hammond using the Peter Dahl design  using DigiKey
>> HV Filter Cap:   Condenser Products
>> other small nuances and tricks i had to use upon request
>>
>> Warm regards:  mac/mc  w5mc
>>
>> On 3/23/2015 10:55 AM, MU 4CX250B wrote:
>>> I was under the impression that the pulse rated tubes were identical
>>> internally to the non-pulse-rated  tubes, except for slightly longer
>>> ceramic insulation that increased the peak voltage rating (and added
>>> more inductance to the internal grid wires.) I know the tubes are
>>> specified for high peak currents, but i thought that was just an
>>> additional specification, not a change in tube construction. If I'm
>>> mistaken, I would welcome being corrected.
>>> 73,
>>> Jim w8zr
>>>
>>> Sent from my iPhone
>>>
>>>> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>>>>
>>>> If you're running a 9500, here is your chance to get that extra 
>>>> tube at a REASONABLE price.
>>>>
>>>> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 
>>>> (8877), capable of handling much higher plate current than the 
>>>> standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, 
>>>> Ameritron or RF Parts (all of which sell Pentas, which are superb 
>>>> tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE 
>>>> BEST tubes for very-high-power amps.  The 3CPX1500 normally sell 
>>>> for $775 and up (way up), but I can ship this one anywhere lower 
>>>> 48, fully insured, for $595. PayPal preferred, other methods 
>>>> acceptable. Tks es 73 N0JR
>>>>
>>>>
>>>> ______________________________________________________________
>>>> ETO_Alpha mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>> ______________________________________________________________
>>> ETO_Alpha mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>> ______________________________________________________________
>> ETO_Alpha mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ETO_Alpha at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
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From w5mc at austin.rr.com  Mon Mar 23 17:16:07 2015
From: w5mc at austin.rr.com (Mac McCullough)
Date: Mon, 23 Mar 2015 16:16:07 -0500
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <55107ECA.2080702@cfu.net>
References: <551015DA.4060600@cfu.net>	<-5234212768510755297@unknownmsgid>	<55107CBB.20005@austin.rr.com>	<55107DC7.9010601@austin.rr.com>
	<55107ECA.2080702@cfu.net>
Message-ID: <55108297.2000102@austin.rr.com>

Jan  my intention was not to slam or knock you in any respect.  what i 
offered was intended to cast the CPX tube in a more correct light, i 
truly while not defending you,  thought you were in a hurry and just 
confused Current and Volts with respect to the tube when you listed 
it..  oddly i was not intending or trying for some sort of pissing 
match, i see you list these type tubes and have for years..all i ever 
intended was support for the tube and a wake up information for guys who 
value the 8877's performance ...If you have construed or inferred 
something else, that is you,  but not intended from me..

mac/mc  w5mc

On 3/23/2015 3:59 PM, Jan C. Robbins wrote:
> About 100 of the top contesters in the world bought 3CPX1500s from me, 
> and a bunch more the 3CPX800s.   So far as I know, they're all still 
> using those tubes, some of them 20 years later. Obviously, none of 
> them knew what they were doing, eh Mac? Just why, I wonder, do some 
> people think engineers designed DIFFERENT tubes for medical, pulse and 
> radar use if the 3CX versions did the same thing. Interesting.
>
> 73 to all, and thanks again for the legitimate inquiries.  Jan
>
> On 3/23/2015 3:55 PM, Mac McCullough wrote:
>> WE ARE talking here about the 3CPX1500A-7 tube  and NOT the 
>> 3cpx800a7  .. sri didn't catch what tube number Jim had listed,  i 
>> was keying off what i had seen as Jan's listing for the 3CPX1500 tube
>>
>> On 3/23/2015 3:51 PM, Mac McCullough wrote:
>>> At the first reading I also noticed what Jan had said about higher 
>>> CURRENT  values for the tube,  but i dismissed it as his push to get 
>>> something listed and not to hopefully overstated the value or 
>>> features of the CPX tube..
>>>
>>> Beginning in May of last year I went on a  "update" of my Alpha 
>>> 77Sx  Soon like most things, the project went big or more. Followed 
>>> by a new HV filter cap and a slight increase in capacitance as well 
>>> operating voltage. Then came the main Xformer followed by a new HV 
>>> rectifier board that has been totally redesigned and updated. All 
>>> the while the moment of effort and truth was fast approaching.
>>>
>>> I was yellow, and punted to Eimac for help.  In two separate calls 
>>> with direct application engineers for the 8877/3CX1500A-7 tube they 
>>> never budged on the HV top rating of 5000 vdc.. My amp was now 
>>> making 4950 idle plate voltage, yes sure they tested it higher, but 
>>> would not move even for idle voltage. Finally we discussed real 
>>> operating conditions and characteristics of the amp proper. This is 
>>> a conversation in it's own self.
>>>
>>> As an off hand comment it was proffered, had i considered the 3CPX 
>>> version of the 3CX tube  I said no never heard of it. Soon enough as 
>>> much data as they would release was here on my computer for review. 
>>> Yes the outward tube design for the CPX gives the white ceramic area 
>>> about a 3/16-1/4" taller profile than the 8877/3CX model.  Outwardly 
>>> that is it. No more.
>>> I was struggling within myself about and even though it was at idle 
>>> the higher right at 5Kv voltage where before the amp had run like 
>>> 3.8Kv at idle, looking at the Plate meter "pegged" or very damn near 
>>> left me no room for comfort and seriously questioning my effort and 
>>> how i had lost the original objective and was now lost in the forest 
>>> of higher Plate Voltage..
>>>
>>> I like the 77Sx  and was just not warming to the idea of the 8877 
>>> and 5kv and operating right at or on the edge..
>>>
>>> The operating and performance spec's for the CPX tube had immediate 
>>> appeal and the 10kv plate voltage spec I was in love with and as Jim 
>>> states it was only for the HIGHER plate VOLTAGE pulse and as it was 
>>> explained to me indeed only the Ceramic body length was increased to 
>>> allow for a slightly higher grid inductance and plate voltage.
>>> I bought into the CPX version and went on the hunt for a pair of the 
>>> damn things.  Soon enough that was accomplished and at what I 
>>> thought was a decent enough price of $375 per tube and while not new 
>>> did come from a medical application and checked almost identical to 
>>> new tube testing numbers.
>>> As for operation is was text book if not easier and quicker in the 
>>> Loading and Tuning to get the amp up and performing, an absolute 
>>> breeze, I had total confidence from the outset and that was not 
>>> misplaced. I have had the 77 since it was new in 85' . It has always 
>>> loaded and tuned well, but now the SWEET spots are or seem very sure 
>>> and easy to walk into and rock back and forth between tune and load 
>>> and just feel and know you are at the best efficiency of all the 
>>> design parameters ...
>>>
>>> Soon after I had the thought of spare tubes and that i wanted a 
>>> set,  none were showing up in the usual haunts, only ebay, United RF 
>>> seems to have as I recall at the time 56 of the CPX tubes listed.  I 
>>> wanted the personal attention and knowledge of the tube so i called 
>>> and soon enough we had agreed on $380.00 per tube incl shipping and 
>>> test results, so i have a set of spare tubes now as well..
>>>
>>> closing notes:  my 77 had the original Eimac 8877 tubes as supplied 
>>> when delivered new and had become weak and not holding the same 
>>> numbers of recorded settings i have recorded for various band freq 
>>> and antennas SWR points .. so that is what started the whole circus 
>>> and $2,400 later not including the spare set of tubes.  If the amp 
>>> last me the rest of my operating life, that i have over invested in 
>>> the amp will be of small concern, reflecting back to 85'  i had to 
>>> hock my ass to buy the thing in the first place.
>>>
>>> Final thought:  I like using the CPX version tube and i don't drive 
>>> the amp any more or harder than i previously did..
>>>
>>> The fellow who is offering the replacement HV boards did a splendid 
>>> job and that was the second 'goal' to replace or just assure the 
>>> performance of the HV rectifier board. over time i had already 
>>> replaced and upgraded the other smaller ckt boards.
>>>
>>> HV board: John Stanford, email is wb8svn at gmail.com
>>> Xformer:   Hammond using the Peter Dahl design  using DigiKey
>>> HV Filter Cap:   Condenser Products
>>> other small nuances and tricks i had to use upon request
>>>
>>> Warm regards:  mac/mc  w5mc
>>>
>>> On 3/23/2015 10:55 AM, MU 4CX250B wrote:
>>>> I was under the impression that the pulse rated tubes were identical
>>>> internally to the non-pulse-rated  tubes, except for slightly longer
>>>> ceramic insulation that increased the peak voltage rating (and added
>>>> more inductance to the internal grid wires.) I know the tubes are
>>>> specified for high peak currents, but i thought that was just an
>>>> additional specification, not a change in tube construction. If I'm
>>>> mistaken, I would welcome being corrected.
>>>> 73,
>>>> Jim w8zr
>>>>
>>>> Sent from my iPhone
>>>>
>>>>> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>>>>>
>>>>> If you're running a 9500, here is your chance to get that extra 
>>>>> tube at a REASONABLE price.
>>>>>
>>>>> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 
>>>>> (8877), capable of handling much higher plate current than the 
>>>>> standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, 
>>>>> Ameritron or RF Parts (all of which sell Pentas, which are superb 
>>>>> tubes). I sold 3CPXs to hams for nearly 20 years, and they are THE 
>>>>> BEST tubes for very-high-power amps.  The 3CPX1500 normally sell 
>>>>> for $775 and up (way up), but I can ship this one anywhere lower 
>>>>> 48, fully insured, for $595. PayPal preferred, other methods 
>>>>> acceptable. Tks es 73 N0JR
>>>>>
>>>>>
>>>>> ______________________________________________________________
>>>>> ETO_Alpha mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>>
>>>>> This list hosted by: http://www.qsl.net
>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>> ______________________________________________________________
>>>> ETO_Alpha mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>
>>>
>>> ______________________________________________________________
>>> ETO_Alpha mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>> ______________________________________________________________
>> ETO_Alpha mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ETO_Alpha at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ETO_Alpha at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>


From swanman at cfu.net  Mon Mar 23 17:42:37 2015
From: swanman at cfu.net (Jan C. Robbins)
Date: Mon, 23 Mar 2015 16:42:37 -0500
Subject: [ETO_Alpha] FS: New unopened 3CPX800A7
In-Reply-To: <55108297.2000102@austin.rr.com>
References: <551015DA.4060600@cfu.net>	<-5234212768510755297@unknownmsgid>	<55107CBB.20005@austin.rr.com>	<55107DC7.9010601@austin.rr.com>	<55107ECA.2080702@cfu.net>
	<55108297.2000102@austin.rr.com>
Message-ID: <551088CD.10405@cfu.net>

I understood that entirely, Mac, and I agreed with what you said.  Sorry 
you thought otherwise; that's my fault.

Your tale reminded me of some others from the 90's and early 2000s.

Bil Edwards built his LK-800 mods to run 5000 watts.  He wanted my 3CPXs 
for them, so they wouldn't burn out tubes.

Pat Stein bought my 3CPXs for his exceptionally high-powered amps, also 
to prevent burn out.

Dick Byrd used only 3CPXs in his Alpha 76 conversions as long as I could 
get him tubes.

But my favorite story, from the 90s, was an international contester 
(i.e., from another country) who called me to ask if I could get him 6 or 8
3CPX tubes.  I asked him what he was running, and it turned out he had 
an Alpha 77SX and a couple of the monster Henrys--8K or whatever
they were.  He said he couldn't keep tubes in them.  It turns out that 
he ran them at 5kw,+ in contests, which was perfectly legal in his 
situation (and EVERYBODY in conesting knew his call!!).  He was forever 
grateful that ON4UN or one of his other DX friends put him on to pulse 
tubes.  He had lots of dough, but a healthy chunk of
it had been going to 3CX tubes!

Just backs up your point, Mac, and I appreciate your kind support.

vy 73 to all!  Jan

On 3/23/2015 4:16 PM, Mac McCullough wrote:
> Jan my intention was not to slam or knock you in any respect.  what i 
> offered was intended to cast the CPX tube in a more correct light, i 
> truly while not defending you,  thought you were in a hurry and just 
> confused Current and Volts with respect to the tube when you listed 
> it..  oddly i was not intending or trying for some sort of pissing 
> match, i see you list these type tubes and have for years..all i ever 
> intended was support for the tube and a wake up information for guys 
> who value the 8877's performance ...If you have construed or inferred 
> something else, that is you,  but not intended from me..
>
> mac/mc  w5mc
>
> On 3/23/2015 3:59 PM, Jan C. Robbins wrote:
>> About 100 of the top contesters in the world bought 3CPX1500s from 
>> me, and a bunch more the 3CPX800s. So far as I know, they're all 
>> still using those tubes, some of them 20 years later. Obviously, none 
>> of them knew what they were doing, eh Mac? Just why, I wonder, do 
>> some people think engineers designed DIFFERENT tubes for medical, 
>> pulse and radar use if the 3CX versions did the same thing. Interesting.
>>
>> 73 to all, and thanks again for the legitimate inquiries.  Jan
>>
>> On 3/23/2015 3:55 PM, Mac McCullough wrote:
>>> WE ARE talking here about the 3CPX1500A-7 tube  and NOT the 
>>> 3cpx800a7  .. sri didn't catch what tube number Jim had listed,  i 
>>> was keying off what i had seen as Jan's listing for the 3CPX1500 tube
>>>
>>> On 3/23/2015 3:51 PM, Mac McCullough wrote:
>>>> At the first reading I also noticed what Jan had said about higher 
>>>> CURRENT  values for the tube,  but i dismissed it as his push to 
>>>> get something listed and not to hopefully overstated the value or 
>>>> features of the CPX tube..
>>>>
>>>> Beginning in May of last year I went on a  "update" of my Alpha 
>>>> 77Sx  Soon like most things, the project went big or more. Followed 
>>>> by a new HV filter cap and a slight increase in capacitance as well 
>>>> operating voltage. Then came the main Xformer followed by a new HV 
>>>> rectifier board that has been totally redesigned and updated. All 
>>>> the while the moment of effort and truth was fast approaching.
>>>>
>>>> I was yellow, and punted to Eimac for help.  In two separate calls 
>>>> with direct application engineers for the 8877/3CX1500A-7 tube they 
>>>> never budged on the HV top rating of 5000 vdc.. My amp was now 
>>>> making 4950 idle plate voltage, yes sure they tested it higher, but 
>>>> would not move even for idle voltage. Finally we discussed real 
>>>> operating conditions and characteristics of the amp proper. This is 
>>>> a conversation in it's own self.
>>>>
>>>> As an off hand comment it was proffered, had i considered the 3CPX 
>>>> version of the 3CX tube  I said no never heard of it. Soon enough 
>>>> as much data as they would release was here on my computer for 
>>>> review. Yes the outward tube design for the CPX gives the white 
>>>> ceramic area about a 3/16-1/4" taller profile than the 8877/3CX 
>>>> model.  Outwardly that is it. No more.
>>>> I was struggling within myself about and even though it was at idle 
>>>> the higher right at 5Kv voltage where before the amp had run like 
>>>> 3.8Kv at idle, looking at the Plate meter "pegged" or very damn 
>>>> near left me no room for comfort and seriously questioning my 
>>>> effort and how i had lost the original objective and was now lost 
>>>> in the forest of higher Plate Voltage..
>>>>
>>>> I like the 77Sx  and was just not warming to the idea of the 8877 
>>>> and 5kv and operating right at or on the edge..
>>>>
>>>> The operating and performance spec's for the CPX tube had immediate 
>>>> appeal and the 10kv plate voltage spec I was in love with and as 
>>>> Jim states it was only for the HIGHER plate VOLTAGE pulse and as it 
>>>> was explained to me indeed only the Ceramic body length was 
>>>> increased to allow for a slightly higher grid inductance and plate 
>>>> voltage.
>>>> I bought into the CPX version and went on the hunt for a pair of 
>>>> the damn things.  Soon enough that was accomplished and at what I 
>>>> thought was a decent enough price of $375 per tube and while not 
>>>> new did come from a medical application and checked almost 
>>>> identical to new tube testing numbers.
>>>> As for operation is was text book if not easier and quicker in the 
>>>> Loading and Tuning to get the amp up and performing, an absolute 
>>>> breeze, I had total confidence from the outset and that was not 
>>>> misplaced. I have had the 77 since it was new in 85' . It has 
>>>> always loaded and tuned well, but now the SWEET spots are or seem 
>>>> very sure and easy to walk into and rock back and forth between 
>>>> tune and load and just feel and know you are at the best efficiency 
>>>> of all the design parameters ...
>>>>
>>>> Soon after I had the thought of spare tubes and that i wanted a 
>>>> set,  none were showing up in the usual haunts, only ebay, United 
>>>> RF seems to have as I recall at the time 56 of the CPX tubes 
>>>> listed.  I wanted the personal attention and knowledge of the tube 
>>>> so i called and soon enough we had agreed on $380.00 per tube incl 
>>>> shipping and test results, so i have a set of spare tubes now as 
>>>> well..
>>>>
>>>> closing notes:  my 77 had the original Eimac 8877 tubes as supplied 
>>>> when delivered new and had become weak and not holding the same 
>>>> numbers of recorded settings i have recorded for various band freq 
>>>> and antennas SWR points .. so that is what started the whole circus 
>>>> and $2,400 later not including the spare set of tubes.  If the amp 
>>>> last me the rest of my operating life, that i have over invested in 
>>>> the amp will be of small concern, reflecting back to 85'  i had to 
>>>> hock my ass to buy the thing in the first place.
>>>>
>>>> Final thought:  I like using the CPX version tube and i don't drive 
>>>> the amp any more or harder than i previously did..
>>>>
>>>> The fellow who is offering the replacement HV boards did a splendid 
>>>> job and that was the second 'goal' to replace or just assure the 
>>>> performance of the HV rectifier board. over time i had already 
>>>> replaced and upgraded the other smaller ckt boards.
>>>>
>>>> HV board: John Stanford, email is wb8svn at gmail.com
>>>> Xformer:   Hammond using the Peter Dahl design  using DigiKey
>>>> HV Filter Cap:   Condenser Products
>>>> other small nuances and tricks i had to use upon request
>>>>
>>>> Warm regards:  mac/mc  w5mc
>>>>
>>>> On 3/23/2015 10:55 AM, MU 4CX250B wrote:
>>>>> I was under the impression that the pulse rated tubes were identical
>>>>> internally to the non-pulse-rated  tubes, except for slightly longer
>>>>> ceramic insulation that increased the peak voltage rating (and added
>>>>> more inductance to the internal grid wires.) I know the tubes are
>>>>> specified for high peak currents, but i thought that was just an
>>>>> additional specification, not a change in tube construction. If I'm
>>>>> mistaken, I would welcome being corrected.
>>>>> 73,
>>>>> Jim w8zr
>>>>>
>>>>> Sent from my iPhone
>>>>>
>>>>>> On Mar 23, 2015, at 7:32 AM, Jan C. Robbins <swanman at cfu.net> wrote:
>>>>>>
>>>>>> If you're running a 9500, here is your chance to get that extra 
>>>>>> tube at a REASONABLE price.
>>>>>>
>>>>>> I have one brand new purchased 2015) Penta pulse-rated 3CPX1500A7 
>>>>>> (8877), capable of handling much higher plate current than the 
>>>>>> standard Eimac or Penta 8877 you buy from, e.g., RF Concepts, 
>>>>>> Ameritron or RF Parts (all of which sell Pentas, which are superb 
>>>>>> tubes). I sold 3CPXs to hams for nearly 20 years, and they are 
>>>>>> THE BEST tubes for very-high-power amps.  The 3CPX1500 normally 
>>>>>> sell for $775 and up (way up), but I can ship this one anywhere 
>>>>>> lower 48, fully insured, for $595. PayPal preferred, other 
>>>>>> methods acceptable. Tks es 73 N0JR
>>>>>>
>>>>>>
>>>>>> ______________________________________________________________
>>>>>> ETO_Alpha mailing list
>>>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>>>
>>>>>> This list hosted by: http://www.qsl.net
>>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>> ______________________________________________________________
>>>>> ETO_Alpha mailing list
>>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>>
>>>>> This list hosted by: http://www.qsl.net
>>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>>
>>>>
>>>> ______________________________________________________________
>>>> ETO_Alpha mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>>
>>>
>>> ______________________________________________________________
>>> ETO_Alpha mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:ETO_Alpha at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>
>> ______________________________________________________________
>> ETO_Alpha mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ETO_Alpha at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> ETO_Alpha mailing list
> Home: http://mailman.qth.net/mailman/listinfo/eto_alpha
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ETO_Alpha at mailman.qth.net
>
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> Please help support this email list: http://www.qsl.net/donate.html