Another standby switch thread

[Tassieviking]

My first tube "anything" did not have a standby switch, but it took about 5 minutes before any noise came out of my 1957 VW Beetles all tube radio.
It freaked some people out how the radio came on all by itself, it just needed time to warm up.

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Well....I wasn't gonna mention it but since you brought it up 

I was reading this the day before yesterday and of course I instantly remembered you talking about your car radio

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Diagram and text Art Margolis

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In contrast (apparently) TV tube heaters are (were) in series

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I guess my job now is to find out if my tube amp heater circuit is like an old TV or the 📻 radio in TV's car 🚗

 

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Ok now it makes sense why in another thread I suspected a tube and G1 had me check for heater voltage ⚡

I bet many innocent tubes are wrongly accused and framed 

[Bjorn210]

Merlin Blencowe argues that you don't actually need a standby switch at all for receiving tubes.

See here

Dave Friedman concurs with Blencowe on this. I haven't noticed a difference but I always have the amp on standby until ready to play and when taking breaks. For shutdown I always just turn the power switch off as it allows the residual current to bleed off faster (or so I've been told by guys who know more than me). Allows the amp to cool down quicker so you're not moving around still warm amps at load out is the line of thought here. 

[Loudthud]

My second real guitar amp was a Traynor YBA-1A. That amp has a whopping 560V main B+. One day the amp took a tumble off the car seat it was on and the Standby switch was broken. I barely got the amp to work that day so I just left the Standby in the Play mode. Several weeks later the amp stopped working. Turns out that without using the Standby switch, that 560V B+ goes all the way to the preamp where the filter cap is only rated at 450V. My first Amp Repair. The 450V cap was shorted and it took out a resistor. I set up a Voltage divider so that Voltage was limited to the preamp filter.   

[DrGonz78]

Turns out that without using the Standby switch, that 560V B+ goes all the way to the preamp where the filter cap is only rated at 450V. My first Amp Repair. The 450V cap was shorted and it took out a resistor. I set up a Voltage divider so that Voltage was limited to the preamp filter.   

My only question would be what is a 450v cap rating? Is it 450v surge current or working voltage? I would assume the 560v would be there for 20-30 seconds decimating before simmering down. I like tube rectifiers! I am truly curious what peak voltage ratings exist for modern capacitors. They are not like motor run capacitors that enjoy absorbing in rush current. I remember Brad the guitologist installing run of the mill electros in his AC unit. It melted or something. Also, isn't a motor run capacitor not concerned with filtering DC current? Unless something is being rectified somewhere.