if so, yes they are fine. Not an absolute 'best', but rugged enough and quite functional.
regards,
Douglas

I used SB5100 which are 100 PIV/5A types I got from Mouser. I soldrered too close for too much time and overheated one. It failed short and when run w/o a fuse in-circuit, toasted my RS filament TX. New RS transformer and from my box a set of the 1N5408's. I found no difference.

It's no big deal I think, but knowing I have Schottky diodes makes me feel better.
regards,
Douglas

If you mean combine silicon P-N junction diodes with Schottkey barrier type, I am not sure. Certainly increased fwd voltage drop. I have a feeling that the lower PIV would have to be observed.

I spoke with a product engineer from Cree about the SiC Schottkey types they had just introduced. He said that they could be paralleded for increased current but increasing the voltage by putting them in series wouldn't work like silicon P-N types do.
regards,
Douglas

Picture this: increase inverse voltage across your 5408's in series. It builds until it reaches brekdown voltage on one. Current would flow and destroy one, but the second, running at less than breakdown PIV does not allow it to pass. One diode runs at breakdown PIV and the extra is taken across the next one.

Since Schottkey types were nor recommended for this service, I think they must short out in over-voltage failure, and fail in a domino falling scenario.
regards,
Douglas