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RE: back on topic how about 160H doable?

Posted by Tre' (P) on June 10, 2016 at 08:38:37

In Reply to: RE: back on topic how about 160H doable? posted by amnesiac on June 10, 2016 at 03:17:18:

From the Lundahl datasheet,

"We define Power Low Frequency Limit, FPL
, as the frequency where LP= R LOAD. (The reactive impedance of
the transformer equals the primary load impedance). At FPL, the output power is reduced to 50%"

I don't think that's right.

If you had a 10k single ended transformer with 80Hy of inductance and you were driving it with a 10k source then at 20Hz (where the reactance of the 80Hy is 10k) the power would be 50%. (10k//10k=5k)

But the 3300 ohm plate resistance of the 211 (for instance) would swamp that equation. So that aside,

What the 10k reactance of the 80Hy of inductance in parallel with the 10k reflected impedance will do is cause an elliptical load line.

With 160Hy the reactance would be 20k at 20Hz so 10k//20k=6.667k and that will still cause an elliptical load line.

And that elliptical load line won't just be for 20Hz.

When low frequencies are present, all the frequencies will be following that elliptical load line and elliptical load lines increase distortion.

TK's 5X or 10X rule would prevent a elliptical load line but I don't see how it can be obtained in a gapped transformer (or plate choke).

Parafeed, using a CCS for the plate load, would work (parafeed output transformer don't have air gaps and have plenty of inductance) but if a plate choke or series feed SE output transformer is used.....using them to play bass seems out of the question.

P.S. I know I didn't answer your question. I don't know how much inductance can be had without causing other problems. Whatever the answer is, I don't think it's enough.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

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