F6 Amplifier

[Zen Mod]

naah

'ts well known who's in charge for that

[buzzforb]

Originally Posted by Zen Mod

nope

just resistor across secondary,creating constant load

same as you walking with or without sack of cement on your shoulder(s)

or constant felt brake under EMT927/930 platter





loading secondary will decrease amplitude

so , speaking of directly altering modulation of gate , not influencing xconductance shape , as with ZAP

I used the word gain and that was wrong as i did not mean gain of the output stage but of the transformer, which would have amplification of less than 1.

[Zen Mod]

exactement

[buzzforb]

Almost.

[lhquam]

I have tried that. I still cannot see a significant difference. I am trying to understand the physical mechanism that secondary loading has w.r.t. distortion.

Originally Posted by Zen Mod

load/unload two secs differently

[Zen Mod]

Pa is talking about different gains for upper and lower halves , resulting in different THD spectra

[lhquam]

Here are actual measurements of the circuit shown in #2213 with a variety of adjustments to the Zen pots P3 and P4. The "spare" primary winding is modulated at 0.8*Vout.

[buzzforb]

Which do you like best?

[lhquam]

I haven't listened yet. I am now modifying the 2nd channel to match.

Originally Posted by buzzforb

Which do you like best?

[lhquam]

I experimented with adjustments to the other PCB which still has the primary windings in parallel. For Gain other than 2.0, I could not obtain distortion spectra comparable to those in post #2237 which has the "spare" primary winding modulated by 0.8*Vout.

If anyone is interested, I can offer an explanation for why the modulation is optimal at (Gain-1)/Gain*Vout.