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@mchsi.com>
>> Subject: [Amps] An Extra Thank You!
>> To: <amps@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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