[Kenwood] TL 922A Tune Up

[Rob Atkinson]

I own a 2 x 3-500 amp, a ten tec centurion.  i believe all of the amps 
using this tube lineup are of the same design roughly, the grids are 
grounded and the cathodes are driven.   what i have always done is tune 
for max power out, then reduce the loading to a point just before the 
power out drops.  you need to have a watt meter on the amp's output if 
one isn't built into the amp.  as someone else said, a string of cw 
dits from the exciter helps to determine the proper tune and load 
settings because pulsing to the amp lets you see more clearly where the 
sweet spots are for your tune and load caps.   you want to keep your 
grid current low v. your plate current, but the Ip for two 3-500s 
should never go past 800 ma.

there are a bunch of mods for the 922.  if you google TL922 mods or 
TL-922 mods you will probably find them.

Also, go to the Amps reflector archive, at www.contesting.com, click on 
amps down at the bottom left side, then click on searchable archive, 
and search tl922 and you will find posts about your amp and dig up 
useful information.

rob/k5uj


On Saturday, July 9, 2005, at 03:27 PM, John Tait wrote:

>
> A tuning pulser is a very useful gadget for safely tuning your amp. 
> Commercial units  are available, or if you'd like to homebrew your 
> own, take a look at http://www.iol.ie/~bravo/Woodpecker.htm
>   73
>     John EI7BA
>
>
>> Jim - K8ARY wrote:-
>>
>>> In the CW mode of the manual, Step 6 of the procedure states: 
>>> "Quickly
>> switch the amplifier to lp and dip the plate". There is no "lp" meter
>> position. There is the IP meter, however that appears to be reading 
>> plate
>> current all the time.
>>
>> Jim....
>>    I don't have a TL-922A amplifier, but I do have a Heath SB-200 
>> amp. As
>> with any tube amplifier, the tuning procedure would be about the 
>> same. I
>> suspect the lp meter you mention above is actually an ip (IP) meter. 
>> IP is
>> an abbreviation for Plate Current, (I=current;P=plate) which is what 
>> you
>> should be concerned about dipping. The idea is to obtain as much RF 
>> output
>> with as little plate current (IP) as possible. As you dip the IP, you 
>> should
>> see an increase in RF output. This is bringing the tube(s) into 
>> resonance.
>> This also works easiest into a dummy load as it's an almost perfectly
>> resistive load, and you won't bother anybody on frequency!
>>
>>> My thought is to leave the meter in the RF position to dip the plate 
>>> and
>> adjusting for maximum output.  What is the correct procedure?
>>
>>    This is basically the same as doing what I suggested above. The end
>> result will be the same...lowest possible plate current for highest RF
>> output.
>>>
>>> I would also be interested in dos and don'ts for this amp.
>>
>>    While doing the dipping and loading of the tube(s), it's best to 
>> use the
>> least amount of drive from the exciter as you're dipping and loading 
>> the
>> final, and gradually increase the drive to the amplifier.
>> Sounds like a lot, but it really goes quite quickly once you've done 
>> it a
>> few times...usually takes less than a minute.
>>
>> Hope the info helps...
>> Cheers....
>> Darrell
>> VA3DG/VE3DDG
>>
>>
>>
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