[Amps] Why 2 3CX800s instead of one 8877?

[Roger (K8RI)]

Why not just punch another hole?

73, Roger (K8RI)

On 4/26/2019 6:36 PM, Alek Petkovic wrote:
> Ha. That's what ya call "thinkin' outside the anode."
>
> Cheers, Alek.
> VK6APK
>
> On 26/04/2019 5:40 AM, Carl wrote:
>> Since a pair of 3CX800's wont even come close to running hard in a 2 
>> or 3 hole 76A series amp then a little careful surgery will do the 
>> trick.
>> Remove enough of the anode cooler from both tubes so that they will 
>> fit with about 1/4" spacing.
>>
>> Dont laugh, it is just a part of hams doing what works when needed.
>> I modified several 8874's decades ago to replace the 8873 in Heath 
>> SB-230 amps. At that time they were cheap as full power medical and 
>> other pulls.
>> My own SB-230 modified for 6M and used for portable and roving has 
>> been fine since 1985.
>>
>> Carl
>>
>>
>>
>> ----- Original Message ----- From: "Colin Lamb" <k7fm at teleport.com>
>> To: "Mike McCarthy,W1NR" <lists at w1nr.net>; "Roger (K8RI)" 
>> <k8ri at rogerhalstead.com>; <amps at contesting.com>
>> Sent: Tuesday, April 23, 2019 8:19 PM
>> Subject: Re: [Amps] Why 2 3CX800s instead of one 8877?
>>
>>
>>> I am somewhat mystified by the messages.  The Alpha 76A has 2 or 3 
>>> tubes 3CX400.  But there is a difference.  The 3 tube version you 
>>> can plug one socket and then use 2 3CX800A7 tubes.  They fit fine.  
>>> I changed one and mounted the transformer inside the unit.  It works 
>>> fine.
>>>
>>> There is a problem with the two tube version.  If you change to 
>>> tubes to 2 3CX800 tubes - the sockets are too close together so they 
>>> do not fit. That would require more work because the holes and all 
>>> the chimenys are too close together.  I have a 2 hole amp and used 
>>> the 3CX400 tubes.  I run that amp at 1200 watts and it has run 
>>> flawlessly for years.
>>>
>>> I did a couple of other things to my amp.  I installed a vertical 
>>> array inside between two meters for grid response. Because these 
>>> LEDs are much quicker that the meter it is much faster and that lets 
>>> me monitor forward output with the meter.  Then, I converted the 
>>> output meter to read peak reading with a meter used for the Bird 
>>> Wattmeter.  I have about 6 amplifiers and with those two changes 
>>> this amp is the one I use day after day.
>>>
>>> 73,  Colin  K7FM
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps 
>>
>>
>> ---
>> This email has been checked for viruses by AVG.
>> https://www.avg.com
>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>

-- 
Roger (K8RI)