[Amps] Carl's and Jim's Words

[Jim]

Speaking of re-reading....


Thanks
73
Jim W7RY

On 3/25/2019 2:09 PM, Carl wrote:
> I hate to break the news to you but I have a few decades more 
> experience building, using, and servicing amps than you can claim so 
> back off on the snotty comments. That includes a couple of commercial 
> ISM products.
>
> Getting back to the 2 holer AL-1500, it will handle ~ 3dB over 1500W 
> and survive if only done for short periods such as in a pileup and a 
> bit of extra air. A stiff 240-250V line is a given as well as using a 
> better PS board if the HV exceeds the cap ratings. In normal use the 
> tubes are loafing.
>
> The tuning networks are up to the users but are easily tweaked if 
> wanted as is an external transformer.
>
> Carl
>
>
> ----- Original Message ----- From: "Jim" <jimw7ry at gmail.com>
> To: <amps at contesting.com>
> Sent: Sunday, March 24, 2019 8:40 PM
> Subject: Re: [Amps] Replacing padder caps on an Alpha 77DX / SX
>
>
>> If you think that adding a second tube double the plate load 
>> impedance....
>>
>> then you don't understand how linear amplifiers work.
>>
>> Now if you double the plate current, (1.8 amps, which a stock AL1500 
>> wont do) then the plate load is half.
>>
>> But the best you could hope for is 1.1 amps or perhaps a little bit 
>> higher on CW or SSB... Then it would certaly increase.
>>
>> Last time I checked, plate load is a function of plate voltage and 
>> plate current. Nothing more... Nothing less.
>>
>> Good luck getting 3600 to 4000 watts output from an AL1500.
>>
>> 73
>> Jim W7RY
>>
>>
>> On 3/23/2019 1:58 PM, Jim Thomson wrote:
>>> From: "Carl" <km1h at jeremy.qozzy.com>
>>> To: "Paul Christensen" <w9ac at arrl.net>, <amps at contesting.com>
>>> Subject: Re: [Amps] Amps Digest, Vol 195, Issue 10--Replacing padder
>>> caps on an Alpha 77DX/SX
>>>
>>>
>>> <And also 2 holer AL-1500's which was as simple as using the AL-82 tube
>>> <chassis and a filament transformer. W8JI pioneered that swap for 
>>> his own use.
>>>
>>> <Never had a report of any failures.
>>>
>>> <Carl
>>>
>>> ##  Very slick !   Is the oem PI net  retained ?   The resulting 
>>> plate load Z  with
>>> a pair of 8877s  would only be one half of a single tube. The 2 
>>> holer would require
>>> double the  tune and load C..and  one half the UH  on each band.
>>>
>>> ##  Was an out board  B+  supply used ?
>>>
>>> Jim   VE7RF
>>>
>>> _______________________________________________
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>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
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