On December 16, 2016 at 00:58, Ernie Gilman said...
I believe I see some misinformation here: The power transformer in the amp provides as high an AC voltage as is necessary to run the tubes, sometimes with B+ on the plates as high as 500 volts. This is not "increasing the line voltage." It's normal and responsible power supply design.
If the plate voltage is higher, how is the transformer NOT increasing the line voltage, whether it's DC or AC? In order for the B+ to be in the 300VDC+ range, the output from the power transformer's secondary must be increased before it reaches the rectifier, where it may/may not pass through without voltage drop.
Does that satisfy your need to correct everything I write?
So there's a voltage surge and Not at all. If you want to generalize, it makes sense to say that tubes are voltage devices (high impedance and high voltage circuitry) while transistors are current devices (low impedance, much higher current draw, and the power transformers for transistor amps always lower the voltage from mains level).
Yes, tubes are voltage devices, but the higher voltage is to overcome the inefficiency of the tube's operation. However, the ratio of the PT's input voltage to output makes it necessary to make sure the components aren't exposed to excessive voltage, for too long and as long as the capacitor's rating is accurate AND leave headroom, it should be OK. A short spike may not kill a cap immediately, but it's not a good thing for the cap.
If a tube gets too much voltage, it may shorten its life. Capacitors are usually rated much above operating voltage. Transistors, on the other hand, get one chance at too much voltage or too much current, and then they open or short. Gone. Dead. One occurrence.
OK, so what is the limit for over-voltage? Can't know, unless we're aware of the device's limitations, so generalization in the protection is required.
SOME protectors might limit the amount of current an amp can draw when you crank it, whether it's a tube unit or a solid state unit.
It could be that the labels are to help you plug your system back in if you take it apart. Some of these products state in their manuals that the outlets are specifically for certain types of products. Some don't.
Some manufacturers say they label some receptacles for amplifiers as such and don't use any protection on those, but it depends on the manufacturer.
This is an anecdote. Are ALL of the power strips and extensions cords in your house made by Furman, with the same level of protection? Are ANY TVs connected directly to the power line? Have ANY devices in your house gotten destroyed during this time? If a TV plugged into a cheapo power strip did not get destroyed, you can't make any claims about the Furman.
Yes, it's an anecdote, but your comment about the transformers being only slightly warm came after being used for a whopping ten minutes. THAT's not proof of long-term reliability. For all we know, they could have worked for eleven minutes, but we don't know if the system was running at capacity, or not because you didn't state anything about that.
The TV that was originally used in the room served by the Furman was moved to the exercise room and it's still running. A new TV was installed in the system fed by the Furman and has had no problems, even after the lightning strike that caused a loud snapping sound in that room when I was there- this sound came from the ADT cellular communicator, which was not using the Furman. Never said it was MY house but I work where this was installed frequently and nobody else services the equipment.
The AVR in the exercise room lost the HDMI board after a storm and it's not on a protection device that's on the same level. The AVR and everything else in that particular rack works fine, though.
This isn't a pissing match- the OP only asked us for comments.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
