Any cathode feedback would have to be wound within the transformer.
The feedback is set up to introduce an opposite-polarity signal into the mix to help flatten out frequency response. There are a number of ways to get it done, the more economical method is a simple resistor off the speaker terminals fed back into an earlier stage of the amp. The cathode feedback winding is an extra cost, though it can work better if the transformer is made properly.
I think for this one, you'd need that specific output transformer to get it duplicated exactly. Maybe someone can wind you one, but there is a more than fair chance you'd have to sacrifice the one you have as a pattern for cloning.
The feedback is set up to introduce an opposite-polarity signal into the mix to help flatten out frequency response. There are a number of ways to get it done, the more economical method is a simple resistor off the speaker terminals fed back into an earlier stage of the amp. The cathode feedback winding is an extra cost, though it can work better if the transformer is made properly.
I think for this one, you'd need that specific output transformer to get it duplicated exactly. Maybe someone can wind you one, but there is a more than fair chance you'd have to sacrifice the one you have as a pattern for cloning.