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Re: I just changed the board-mounted footswitch on my pedal.


 
3/23/2005 5:40 AM
KB
email
Re: I just changed the board-mounted footswitch on my pedal.
That's pretty rough stuff just to change a switch but on the good side you do have true bypass. The only thing about pcb's is the more you handle them the greater the chances of a trace breaking,cracking,ect.. or even a cold solder joint. The switch should last a good while though hopefully.  
 
Your right about 12AX7's lasting 10 to 20 years is not a problem however, what kills these dual-triodes is turning them on and off several times not plate voltage. The heater to cathode insulation will break down and filaments will burn out mainly because of in-rush currents when turned on. Many amps hve ramp-up timers are RC networks to gradually step the current up to prevent this. Tube rectifiers do it automatically. My buddy has a 65 Deluxe that has tele 12ax7's that are 25 years old and they are awesome. The sad thing is they sound their best when they are about to go. doh!,  
 
KB
 
3/23/2005 12:42 PM
anonymous
I'm not getting a clear picture of this.  
You seem to be saying that tube reliability is compromised by filament turn-on-off.  
How does a rectifier tube mitigate this automatically?
 
 
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3/23/2005 6:29 PM
KB
email

ha ha ! you got me on that one anonomous. I should have said it ramps the high voltage supply not filaments however an RC time delay will ramp them up slower but a rectifier will only limit the high voltage as all of the filaments are on a seperate winding from the rectifier on most 5 volt supplies. Turn on or in-rush current does still wear your tubes out faster than a rc supply will. btw what is anonomous ?,  
 
KB
 
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