[TenTec] Fw: Ten-Tec 411 Centaur Amp Problem

[Dr. Gerald N. Johnson]

A single 811 usually has a cathode Z of about 200 ohms, so three in 
parallel would be 67 ohms and put that in parallel with 150 ohms makes 
50 ohms.

The low pass filter has the only reactive components in the circuit, so 
there must be a problem with it. I presume its the replacement filter 
that passes 10 meters and I don't have the diagram for it.

73, Jerry, K0CQ

On 6/1/2010 11:42 AM, CSM(r) Gary Huber wrote:
> Ooops, I should have stated the input resistor as 25W at 150 Ohms.  Still it is in parallel with the cathodes of the THREE grounded grid 811s, so the input SWR should be 3:1 or less when the source impedance is 50 Ohms. Calculate the needed coax length (between the source and load) by multiplying the velocity factor of the cable times the electrical wavelength of the frequency of operation.
>
> Manual at: http://www.tentec.com/files/Model%20411%20Centaur%20Owner%20Manual.pdf .... Input schematic, manual page 5-8 (PDF page 43)
>
> 73,
>
> Gary - AB9M (just a Ham doing applied electronics)
>