Peavey 5150 switchable mods

You should never toggle switch a choke. It’s got 400+ volts on it. I really don’t know why you’d want to anyway.
 
I was curious I had seen a video with a fella that had a switchable choke and trying to figure out how n hell he figured it out I'm sure it's possible but the circuit would be far beyond my understanding.im a little embarrassed for asking but you know......why not'????
 
dannykookoocookjr said:
I was curious I had seen a video with a fella that had a switchable choke and trying to figure out how n hell he figured it out I'm sure it's possible but the circuit would be far beyond my understanding.im a little embarrassed for asking but you know......why not'????
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Because they store energy in the form of a magnetic field and when you break the contact the amount of electromagnetic energy that will be released is greater than any direct switch’s voltage isolation potential which means it will arc and could potentially fail when doing so causing immediate harm to the user. If you get lucky and it doesn’t arc it could stay energized and create a speaker shattering pop when you connect it back into the speaker. It also wildly swings the inductive impedance response the tubes see on the plates which could also cause premature tube failure. Additionally chokes provide noise isolation and there isn’t a need to ever switch one out of circuit. It’s just not a component you should design a switching mechanism around.
 
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JerryP said:
You all do realize the standby switch switches the choke/HV in/out right?
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It switches supply and one side is attached to ground through the rectifier to discharge. In a mod where there isn’t a discharge path (B+ is still present) it’s not quite the same thing. Also the switch is rated for B+, most small toggle mod switches aren’t. Also in 5150s the standby is in the worst location and is a common gripe. It should be moved to minimize arcing/premature failure stock as is.
 
No ment
glpg80 said:
Because they store energy in the form of a magnetic field and when you break the contact the amount of electromagnetic energy that will be released is greater than any direct switch’s voltage isolation potential which means it will arc and could potentially fail when doing so causing immediate harm to the user. If you get lucky and it doesn’t arc it could stay energized and create a speaker shattering pop when you connect it back into the speaker. It also wildly swings the inductive impedance response the tubes see on the plates which could also cause premature tube failure. Additionally chokes provide noise isolation and there isn’t a need to ever switch one out of circuit. It’s just not a component you should design a switching mechanism a
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Still curious…why would you want this switchable? I can think of a million other things that could be switchable and have a much greater effect on the tone.

In that video you can clearly see he just used a large standby-type toggle switch on the back panel. I’m sure he’s turning the amp off before switching it. As said above, it can be done. But shouldn’t be. Just because some YouTube guy did it doesn’t make it a good idea.
 
Thanks for all of your input.please excuse my ignorance I am very intrigued with all amp design and modification again I totally appreciate all input
 
Aside from the question of why you'd want to switch it, what's wrong with just sticking an appropriately rated TVS diode in to provide a discharge path upon switching? I know the added capacitance might mess with things a little, but presumably that could be worked around?
 
7704A said:
Aside from the question of why you'd want to switch it, what's wrong with just sticking an appropriately rated TVS diode in to provide a discharge path upon switching? I know the added capacitance might mess with things a little, but presumably that could be worked around?
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They add a lot of noise
 
You could use a flyback suppression diode to control the spike. Solving a problem that shouldnt exist imo
 
glpg80 said:
It switches supply and one side is attached to ground through the rectifier to discharge. In a mod where there isn’t a discharge path (B+ is still present) it’s not quite the same thing. Also the switch is rated for B+, most small toggle mod switches aren’t. Also in 5150s the standby is in the worst location and is a common gripe. It should be moved to minimize arcing/premature failure stock as is.
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Never changed a 5150 standby switch and I've worked on more than most.
 
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