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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6c45pi amp

A while back I built this tiny amp and really liked the 1 w or so output. Has anyone here built it and know the output impatience. I know I could measure it but the oscilloscope isn't working right now and it's cold in my unheated work space anyhow.
 
With no negative feedback:

Take a typical 6C45 plate resistance, rp, 2250 Ohms approximately (if i remember correctly).

Take a lossless output transformer with 5k primary.

5000/2250 = 2.2 damping factor.

Lossless 7500 Ohm primary: 7500/2250 = 3.3 damping factor.

Different rp?
Different primary impedance?
Lossy output transformer with high DCR in the primary or secondary?

Suppose the primary DCR is 250 Ohms.
5000/(2250 + 250) = 2.0 damping factor.

Your Mileage May Vary
 
Last edited:
With no negative feedback:

Take a typical 6C45 plate resistance, rp, 2250 Ohms approximately (if i remember correctly).

Take a lossless output transformer with 5k primary.

5000/2250 = 2.2 damping factor.

Lossless 7500 Ohm primary: 7500/2250 = 3.3 damping factor.

Different rp?
Different primary impedance?
Lossy output transformer with high DCR in the primary or secondary?

Suppose the primary DCR is 250 Ohms.
5000/(2250 + 250) = 2.0 damping factor.

Your Mileage May Vary

Rp about 1200 Ohm ,+ -
https://tubedata.altanatubes.com.br/sheets/112/6/6S45PE.pdf