[TenTec] Care and Feeding of Centurions

[Bob McGraw - K4TAX]

You mean some folks actually read the manual?  I thought they were just told 
the right way to do it by some other non knowing ham that had the info 
passed down from generation to generation.

73
Bob, K4TAX


----- Original Message ----- 
From: "Bry Carling" <bcarling at cfl.rr.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Sunday, February 02, 2014 4:15 PM
Subject: Re: [TenTec] Care and Feeding of Centurions


> Ten Tec has some very good detailed instructions on tuning in their 
> manuals. It is quite clear.
>
> I apologize for any duplicate messages today. My iPhone was misbehaving 
> again !
>
> Best regards - Bry Carling
>
>
>
>> On Feb 2, 2014, at 5:01 PM, "Bob McGraw - K4TAX" <RMcGraw at Blomand.net> 
>> wrote:
>>
>> I fully agree with Jim on the point that grid current is the most 
>> critical value to watch and adhere to in terms of extending tube life.
>>
>> For a pair of 3-500's the total grid current should NEVER exceed some 230 
>> to 260 mA MAX!    This is in tune mode with carrier.  Operationally, with 
>> SSB the grid current meter would typically display 100 to 130 mA on voice 
>> peaks. Plate current in tune with carrier, should be between 700 mA and 
>> 800 mA MAX and with SSB, the plate current meter would typically display 
>> 300 to 350 mA on voice peaks.  If ones amp while in SSB operation is 
>> exceeding these values, likely the tuning is not correct or the amp is 
>> being overdriven.  In either case, it is bad for the amp and worst for 
>> the stations on either side of your frequency.
>>
>> If you wish to operate at less than rated or maximum power, always tune 
>> the amp for maximum rated power using the correct values for grid 
>> current, plate current and power output.  Then simply reduce the drive to 
>> attain the desired operating power.  NEVER retune the amp for the lower 
>> power value.
>>
>> I'll say this and likely get in a bit of hot water with some folks 
>> but..........for those that profess to "dip the plate",  this is correct 
>> for a Class C amplifier, but NOT SO for a linear amp in Class AB1 or 
>> Class AB2 service.  Always tune for maximum output.
>>
>> We'll not discuss "tuning to the right side of resonance" as it applies 
>> to the tuning a Class C amplifier.  However, you old BC folks will 
>> certainly understand this term.
>>
>> 73
>> Bob, K4TAX
>>
>>
>>
>>
>>
>>
>>
>>
>> ----- Original Message ----- From: "Jim Brown" 
>> <k9yc at audiosystemsgroup.com>
>> To: <tentec at contesting.com>
>> Sent: Sunday, February 02, 2014 2:31 PM
>> Subject: Re: [TenTec] Care and Feeding of Centurions
>>
>>
>>>> On 2/2/2014 12:03 PM, Bob McGraw - K4TAX wrote:
>>>> Proper tuning and loading and proper drive is the key to success for 
>>>> long amp and tube life.
>>>
>>> And also the key to having a cleaner signal. An amp that is over driven 
>>> (using AGC to control the drive power) or that is not well tuned will 
>>> generate lots of splatter, clicks, and other trash.
>>>
>>> I don't know about the 3-500Zs used in the Centurion, but the key to 
>>> long life for the ceramic triodes used in the Titan is to keep the grid 
>>> current below its limits at all times. My objective is to keep the grid 
>>> current below half it's rated value, and my tubes last a LONG time. Grid 
>>> current is minimized when the amp is well tuned and not overdriven.
>>>
>>> 73, Jim K9YC
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec at contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>