6L6GC to KT66 filament question

[EFK]

If anyone knows: is it possible, when swapping in KT66 for 6L6GC, if the added filament/heater draw can somehow damage the bridge rectifier converting the AC to DC for the heaters? I tried the swap and pulled my reverb/trem pre tubes to make sure there was a surplus of current for the KT66 w/o taxing the transformer, but after @ 5 hrs of play time my bridge rectifier started to go south and eventually died. I replaced it w/ a Fairchild GBPC1210W which is much bigger than original, probably overkill, and went back to 6L6. I'm wondering if this was just a coincidence - I can't see how the slightly higher heater current per tube would really harm the rectifier - or if the KT66 1.3 draw vs. the 6L6 0.9 actually did something to it. ??? I suppose I could pop the 66 back in there and swap out the resistor again (cathode bias) but I don't want to kill another rectifier if in fact it's the tubes. Anyone?

[rockon1]

I always read the danger was to the PT but unfortunately Im not that well versed. FWIW- The NS "Tung Sols" draw the same heater current as 6L6's. Bob

[Roe]

the bridge rectifier should not be affected since the heaters are ac. amps with dc filaments have a dedicated rectifier for the filaments.
Valvearts actually draw very little current. original GECs draw a lot however. are your PT hot?

[EFK]

These are DC filaments - the rectifier is dedicated as it is used only for converting the AC to 6.3-6.5 DC for the heaters, nothing else. That's why I was wondering if the tube swap did something to it or if it was just coincidental that it happened at the same time I tried changing tubes. These were Groove Tubes (Chinese, not Russian) but I have ValveArts as well. I just barely have room for the 66, only tubes w/ the original shape will fit (Tungsol and JJ are far too big). The PT seemed just fine through all this, not hot at all, but as I mentioned I had pulled V3 and V4 preamp tubes (reverb and trem only) while testing to ensure that there was enough current available.

[Roe]

most ss rectifiers are way overspec'ed

[donnyjaguar]

Its entirely possible you blew the bridge. Normal failure mode is a short circuit which should take out the line fuse. I'm big on DC filaments, but generally wire the output tubes with AC. This would've got around the problem you had. Bbecause they draw the most current and generally don't benefit from DC filament voltage due to the hum-canceling nature of the output transformer in a push-pull topology I do it this way. I've seen others do it too.