[Amps] An Extra Thank You!

[Roger]

Jeff Carter wrote:
> Congratulations!  It's such a rush to work on something like that and
> see it work when you're done.
>
> To answer your questions, I have to say it's been a while, and I'm
> sure AMPS will jump in and correct me if I'm wrong, but here's how I
> *think* I remember that this is done.
>
> For gain in dB, I think it's 10*log(power out/power in).  So in your
> case, it's 10*log(450/20), or 10* log(22.5)= 13.5218251811 db.
>
> For efficiency, it's basically how much of the power is used and how
> much is turned into heat, and I can't for the life of me remember how
> that's calculated.
>
>   
IIRC For efficiency it's pretty straight forward it's power out divided 
by power in (not drive) IOW in this case for GG it's Plate current Ip 
(0.375 * multiplied by plate voltage. I don't remember what you are 
using for voltage, but as n example if the plate is 2200 then 
0.375A*2000V=750 Watts input power plus 20 watts of drive for 770  watts 
input  or 450/770 = 58% overall efficiency for the amp.  The tube 
efficiency would be 450/750 or 60%

73

Roger (K8RI)
> I bet Dan knows...and he's much better with the math than I am.
>
> Jeff/KD4RBG
>
> ---- Original message ----
>   
>> Date: Thu, 5 Mar 2009 14:39:35 -0600
>> From: "KB0NLY" <kb0nly at mchsi.com>
>> Subject: [Amps] An Extra Thank You!
>> To: <amps at contesting.com>
>>
>> Just wanted to post an extra Thank You to the reflector for all those that have been patient with me and helping.  My 6M amp project has been completed!  It was powered up and brought to life today finally after much careful planning and building.
>>
>> Initial tests prove it's working rather well!
>>
>> Input 20w
>> Output 450w
>> Plate 375mA
>> Grid 80mA
>>
>> I was told to keep the GI7B at or below 400mA on the Plate and 150mA on the Grid, i can do that easily.  It will make a bit more power but it's maxing out my wattmeter now!
>>
>> I do have one final question for everyone here.  Knowing these numbers, input, output, plate and grid, how does one calculate the amp's gain and or efficiency?  I was trying to make sense of the info in the handbook but it was slightly over my head with all their calculations.  I'm looking for an Elmer answer on this one!
>>
>> Thanks and 73!
>>
>> Scott KBØNLY
>>
>> PS:  I will finish updating my website this afternoon with pictures of the completed amp.
>>
>> www.kb0nly.net
>>     
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