It is generally accepted that the key features of OTL circlotron topology are:
- no even order harmonics
- vanishingly small distortion at low level
- predominat third harmonic at high level
The above appears to be confirmed by the following LTSpice simulations.
I know that most seasoned engineers think that SPICE 'does lie'.
Even though I am seasoned too I think that SPICE is a very useful tool for DIY design of HI-FI tube amplifiers.
As it is not fair to simulate the circuits of others I have used this simple one of my own creation.
And in order to retain some correlation with the results of those inmates who do not like feedback at all the components values have been adjusted for 3 dB feedback - 1V peak input for 1.8A peak @ 8 Ohm.
The simulated spectra follow.
Best Regards
Luca Cellai
ecc230
