Hi All,
I don't remember where, but I've read somewhere that the impedance ratio of a modulation transformer has influence on the audio response.
I.e, I have build class b 2x811a modulator. I'm planning to build a plate modulated single 813 class c amplifier.
The modulator runs (currently) on 1100v. According to the tubedata, it would have a plate to plate impedance of around 11k
The 813 will run on approx 1300v and will have an impedance of around 9k
The optimum transformer ratio has to be 1:1.2
From what I've read, is that a ratio close to 1:1 will affect the audio response.
Am I wrong?
When it is true, would it be better to use a higher ratio transformer and live with the mismatch?
PA4WM
The transformer ratio will affect the maximum % of modulation available, not the frequency response.
Don't worry too much about impedance mismatches. A good rule is to use all of the secondary winding of the transformer, "all of the copper", don't use the secondary taps unless there are extreme circumstances.
Bill