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RE: What tubes to use with this Interstage Transformers?

hey...

Why aren't you seeing it? It's beyond me. You don't have to do FFT. And your FFT looks way bumpy to me for a sine wave.

I don't think I am seeing it because it isn't there. Why cant you post an example rather than a vague description? Plus that FFT ispretty nice for a 20hz sine... the 2nd and third harmonics are approaching -60dB which is in the area of 0.02% distortion.


According to your own circuit with 5K resistor limiting to about 4mA-40mA (actual number depends on the actual source impedance of the FG) of current driving into a parallel circuit that has low value DCR of less than 50-100ohms, unknown value C but a large value of L in series with the rate of charge of 20 cycle, you will have a resulting vector of triangular output due to the charge due to the very limited current. That triangular output is now reflected back to the source and combined into a pretty distorted sine wave.

if this is the case then it should really be easy to see. To make things easier to document I moved to spice to do the circuit and again I couldn't replicate this distortion.

Here are a series of 4 different traces at three different point in the circuit representing a source impedacne of 50 and 5000 ohma and a coil capacitance of 1p, 1n and 1u. If this behavior really exists I would expect ot see at least a hint of it in one of the simulations.





To overcome this, you either need to increases the frequency (charge the C of the primary winding more rapidly) or increase the current to charge the capacitance of the winding at every cycle. It's exactly what I envisioned and exactly what I see.

again please show me some measured or simmed results of this behavior.

Or the result is incomplete charge cycle resulting in a triangular shape waveform. It's the same principle as ripple in Power Supply circuit.

I have yet to see a triangle and pretty thoroughly covered all the things you have said will cause it.

What's the point of using such distorted waveform since it'll only make everything worse?

the waveforrm isn't distorted so no problems with the measured results.

This claim of distortion is yours and I have done everything to try to find it. Rather than sitting there behind a keyboard and insisting it happens why don't you replicate it and post the results? The perfect place to do this would be with the test setup you have already done to measure the transformer in question. Simply measure the output at 1Khz with and without the 5K series resistor and then repeat at 20hz with both. Then a quick pic of the resultant sine for each case should clearly show the problems you insist will happen.

dave


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