SE OPT Arcana

[popilin]

I have the same scope!!

Lucky you, I have a very old one, the picture is borrowed from the web, Tamura transformers are also long way from my budget, that’s why I wind them for myself.

Well, the HF bias scheme works good for tape recording. I think we all need to differentiate between domain flipping and domain avalanching. Avalanching is what is producing near audible effects. The magnetic material is like a pile of sand with "stiction" between granules. The HF bias shakes the pile so that it all flows more like water, preventing any buildup of cliff-hanger domains that will avalanche.

Are you serious? On post #38 you advocated for very slowly voltage change to reduce BN, and now high frequency?

Putting an air gag (edit: ha-ha, I meant air gap!) into the magnetics to flatten permeability down is highly counterproductive. That just lowers the whole magnetics curve permeability by 100X, so everywhere is as bad as near the zero crossing. Magnetizing current becomes 100X bigger. That's just trading a minor problem for a major problem.

At least in this universe there is conservation of charge, so in SE OPT current flows always in the same direction, so there is NO zero crossing.

Linearity depends on how constant is magnetic permeability along the magnetic hysteresis curve, you must lowering magnetic permeability to increase linearity and avoid saturation due to DC current flow.

BTW, the transformer in the picture is a SE Tamradio (Tamura) F-2013, so increasing magnetizing current is not that bad, isn’t it?

 

[45]

Amorphous and Nanocrystalline materials, puaj!!!

Fushta! 😛😀

Never used one. I honestly don't know.

 

[45]

By the way I really don't understand such doggedness to demonstrate something that in reality doesn't happen.

 

[45]

increasing magnetizing current is not that bad, isn’t it?

Higher magnetizing current for a PP transformer is not that useful. The increased distortion at zero crossing is appreciable (on the analyzer, likely not by listening but depends on the specific case) only when one wants to use a SE transformer in a PP amplifier (i.e. Bac>Bdc with heavily gapped core).

You can see this by taking the REAL hysteresis curve in the three cases: no gap (i.e. just natural gap) or a small gap (in comparison to its typical SE use); 2) gapped and used in SE mode (i.e. Bdc>Bac); 3) Like in case 2) but used in PP mode.

Case 3) is the only one where zero crossing causes a bit more distortion. One can see a sort of bubble around zero on the B-H curve.

Case 2) has no zero crossing but the distortion of the amplfier is higher of them all nonetheless.

Case 1) has zero crossing with no consequence on distortion due to transformer. The fact that it is less linear than the gapped case doesn't cause any trouble to the PP stage as this is miles less sensitive to load variation and inductance is huge in comparison to SE case anyway.


So it's witch hunting again.....😀

 

[Moderation Team]

OT posts have been removed, and the thread is closed.