[Amps] Low power output from 4-400A linear

[GGLL]

	I want to second a previous post which asked about loading. Is your amp fully
loaded?, because Ig is somewhat high and plate current has what I guess is a
one tube value at full output.

Best regards
Guillermo - LU8EYW.

Scott Townley escribió:
> Numbers according to Eimac in parentheses:
> 
> 
>   Measured power out: 855 watts  (1200)
>   Power input: 1216 Watts (1980)
>   Ep:3200 Volts   (3000)
>   Ip: 380 Ma.( at max output)  (660)
>   Ig: 250 Ma.            (200)
>   Eg: Bias 00            (0)
>   Static Ip: 120 Ma.     (140)
> 
> PS that would all be with 80 watts drive.
> 
> Not an expert, but sounds like the plate impedance is too high.  That would 
> give low Ip and high Ig.  According to the datasheet it should be ~2500 
> ohms for two in parallel.
> Really the question is, what's the screen current?  I would think that even 
> in g-g/triode-connected service the screen current is a key indicator.
> 
> I don't recall the exact bits but the 850A isn't tapped correctly as-is 
> from the factory.  Obviously it will resonate with the right tune-C but the 
> Q is way off from what you normally shoot for.
> 
> 
> 
> At 07:27 2005-10-11, Bruce Lanning wrote:
> 
>>Several years ago, I built a GG amplifier using a pair of 4-400A. The grid
>>and screen are grounded at the tube socket.
>>
>>I feel that the power out is quite low. Below are some of the operating
>>parameters:
>> Measured power out: 855 watts
>> Power input: 1216 Watts
>> Ep:3200 Volts
>> Ip: 380 Ma.( at max output)
>> Ig: 250 Ma.
>> Eg: Bias 00
>> Static Ip: 120 Ma.
>>
>>I am using the B&W Pi-network, model 850A output tuning inductor
>>.
>>I have checked the tube filament pins for a poor solder joint.
>>They both looked OK, but I resoldered them to no avail.
>>
>>Maybe someone out there could throw some light on my problem, or if I even
>>have a problem...
>>
>>
>>
>>
>>
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> 
> 
> 
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