Here follow some simulations and measurements about the use of ECW20N20 instead of old 2SK1058.
Both are lateral type mosfet with negative temperature coefficient so these are stable without a compensation of Vgs.
As show in the simulation the output impedance with 2sk1058 is 1.36ohm and with ECW20N20 only 0.4ohm.
The distortion measurements are incredible because without feedback with only 2 mosfet we get 60W on 8ohm and 100W on 4ohm.
The main benefit of a Circlotron design is an high power amplifier with no switching output stage like a pure class A but higher efficiency, with only 1A bias current still have 1mA with 2.3A on 8 load (see last image).
The anodic voltage for the 6Z51 should be reduced to 140-150V.
Tell me if you find other lateral mosfet with the same performances.
Both are lateral type mosfet with negative temperature coefficient so these are stable without a compensation of Vgs.
As show in the simulation the output impedance with 2sk1058 is 1.36ohm and with ECW20N20 only 0.4ohm.
The distortion measurements are incredible because without feedback with only 2 mosfet we get 60W on 8ohm and 100W on 4ohm.
The main benefit of a Circlotron design is an high power amplifier with no switching output stage like a pure class A but higher efficiency, with only 1A bias current still have 1mA with 2.3A on 8 load (see last image).
The anodic voltage for the 6Z51 should be reduced to 140-150V.
Tell me if you find other lateral mosfet with the same performances.
Attachments
20N20 are double die devices, the additional performance should not be a surprise. Try 2x SK1058 for a more apt comparison, or the ECX/ECF10N20.