Fisher KX-100 preparing for Rebuild

[sony6060]

A picture of a KX-100 with a Fisher 400 transformer set in place. The 400 transformer is larger than the stock KX-100 transformer.

Besides the higher HV current capacity, the transformer has a bias winding for fixed bias. The Fisher 400 transformer also has a higher current filament winding vs the stock KX-100 transformer. A small value resistor may be needed to dial in 6.3 volts filament.

This KX-100 will be changed from cathode to fixed bias. A benefit per Audiodon's similar X-101C amplifier rebuilt by Dave. See Dave's article published here at AK.

 

[audiodon]

I can't quite judge the height of the power tranny. Will it still fit in a case when done?

 

[Dadbar]

Making a separate DC supply for the 12AX7 string is a wonderful thing.

The impedance of those trannies, though, may be more friendly to cathode bias. I wouldn't be surprised if you wind up going back to it after trying this with fixed bias.

 

[audiodon]

Actually Dave said the output trannies on my X-101-C running 7591s were Fisher 400 trannies.

 

[sony6060]

Actually Dave said the output trannies on my X-101-C running 7591s were Fisher 400 trannies.

Oh, 400 trannies. We have different audio transformers. The 400 lam stack is 1-5/8" and the KX-100 lam stack is 1-1/4".

Upon power up, one audio transformer has a primary to secondary short. :scratch2:

 

[sony6060]

I can't quite judge the height of the power tranny. Will it still fit in a case when done?

Yes, height of the original and Fisher 400 power transformers are identical.