"The mains-side filter caps for switching supplies tend to be large in capacitance (100-200 and > uF), and typically are not suitable for replacing the ~ 8-40uF B+ filter caps in vintage tube electronics that have tube rectifiers."
This is true. All of the common vacuum diode rectifiers have fairly significant limitations, for the 1st cap in a cap-input PSU. Devices like the 5U4 and 5AR4 might tolerate as much as 40-80uF at the first pole (which is still fairly light), while others such as 5V4 might only tolerate as little 4uF. Point of my post - it seems as if the tube audio folks were being blamed and/or shamed for the cost of high-voltage electrolytics.. and if anything, they keep both the volume and demand up, and the prices reasonable. On Wed, Nov 16, 2016 at 11:37 PM, Brent Hilpert <[email protected]> wrote: > On 2016-Nov-16, at 8:44 PM, Jon Elson wrote: > > On 11/16/2016 10:10 PM, drlegendre . wrote: > >> "Note the "tube audio" folks gravitate to that stuff and tend to cause > >> seriously sick prices, because tubes." > >> > >> > >> FYI - I've installed dozens of the new-production CE / Mallory caps, > all of > >> them in the 350-525V range. Zero complaints, zero comebacks, in as long > as > >> I've installed them. For those of us in that field, they're like a gift > >> from the gods. > >> > > Vintage tube audio doesn't need to get involved, except for the > old-style twist-lock Mallory cap design. > > All the off-line switching supplies use either 250 V (120 supply only) > or 400+ (120/240 supply) capacitors as the main input filter. So, at least, > capacitors in that voltage range are STILL being made, and are in all > computers, TVs and other home appliances. (Yes, I know the OP needed a 30 > V cap.) > > > > So, some other tube gear replacement parts may be scarcer than hen's > teeth, but the HV caps are easily available. > > (tending off-topic . . ) > > As long as one is being careful about the size (capacitance) of the > replacements. > IME, I've found limited benefit in trying to use/source/scavenge > switching-supply caps for tube gear. > > The mains-side filter caps for switching supplies tend to be large in > capacitance (100-200 and > uF), and typically are not suitable for > replacing the ~ 8-40uF B+ filter caps in vintage tube electronics that have > tube rectifiers. > > Maybe there are smaller ones in the smaller switching supplies around > these days, I haven't looked at those recently.
