[Amps] Power output drop

[Vic K2VCO]

Yes, if it's the caps then retuning would bring it back up.

I looked at the pix on your website and I see you have a bunch of 0.01 discs in parallel 
in series with the input. There is probably some heat being generated there, since a lot 
of current flows. A 0.1 uf transmitting mica would be better. Of course the value isn't 
critical, so that might not be the problem.

Regarding your comment about the Shurite meters bouncing: a simple solution is to just put 
a capacitor across them to damp them out. I used such meters in one of my first HB 
transmitters back in 1957!

On 9/10/2013 6:35 PM, Mike Waters wrote:
> Thanks, Vic. Someone else (in a private e-mail) just suggested line voltage. I do monitor
> the filament voltage, but I should monitor the 240 VAC and look at the HV meter, too.
> There is a "too-long" run of #12 from the breaker panel to the amp, and if that wiring
> heats up, that might do it.
>
> As for the pi-net caps, that's what I thought at first. I have padder caps --some with a
> high negative temp coefficient--- on both C1 and C2 in the pi-net output. However,
> re-tuning should compensate for that and bring it back up to full power out (shouldn't
> it?), but it never does.
>
> 73, Mike
> www.w0btu.com <http://www.w0btu.com>
>
>
> On Tue, Sep 10, 2013 at 8:29 PM, Vic K2VCO <k2vco.vic at gmail.com
> <mailto:k2vco.vic at gmail.com>> wrote:
>
>     Does the line voltage droop when you transmit, causing a drop in filament voltage?
>
>     Do you have ceramic capacitors in the tank circuit that heat up and detune the tank?
>
>
>     On 9/10/2013 6:03 PM, Mike Waters wrote:
>
>         `
>         Anyone have an idea why the power output of my dual parallel 833C 160m amp
>         often drops 200+ watts after several seconds? Re-tuning does not bring it
>         back up to the initial output.
>
>         Not that a drop from 1500 to 1300 watts is a big deal, but inquiring minds
>         want to know the reason. :-)
>
>         Description:
>         www.w0btu.com/833C_linear_amplifier.html
>         <http://www.w0btu.com/833C_linear_amplifier.html>
>
>         More photos:
>         w0btu.com/files/misc/833C_linear_amplifier/?C=M;O=D
>         <http://w0btu.com/files/misc/833C_linear_amplifier/?C=M;O=D>
>
>
>     --
>     Vic, K2VCO
>     Fresno CA
>     http://www.qsl.net/k2vco/
>
>

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/