Experience with FREDs in a tube amp PS

Generally speaking, the safe thing to do is to select replacement diodes that equal or exceed the rated capacity of the stock bridge. Chances are good that this can be done without using heat sinks, unless the original rectifier uses them.

It's definately worth using Schottkys if you can figure it out-- both for B+ and for the low voltage filament supplies.

Those Crees do really look interesting. A bridge of four TO-247's (1.2kV/10A) would take up a bit of space though. The 5A package(TO-220) is only slightly smaller, and I'd really like to have heatsinks on them. This is obviouly going to have to wait until after the holidays($$). I'll be doing the three bridges(600V) in my Hafler TransNova 9505 (woofer amp) too. That's twenty SiC Schottky diodes, and eight of those need to be 25A. HMMM- I wonder if the kids have bought my presents yet?

OH(BTW)- No soft-start. I can tell by what my lights do when I turn the amps on.

FREDs and Schottky diodes will mostly clean up the treble.
If you are looking for more transparency and dynamics, I suggest that you upgrade the amplifier coupling caps.

A few suggestions:
Low cost: Auricaps & Hovland
Medium cost: Mundorf Silver/oil
Expensive but the best IME: V caps TFT by VH Audio.

I've got Aeon polypropylene coupling caps in my mains now which will do for the time being. I'm focusing mainly on power supply upgrades for the woofer and main amps right now. Overall system dynamics and speed are what I'm after.