How to power on amps with no on/off switch?

In terms of a safety rated switch snubber, it would be wired across hot out and neutral at the switch or it could be wired across the hot and neutral on the outlet. With my ODCness, I prefer to have it as close to the switch as possible in high surge current applications.

Unless I am missing something, there is no neutral at the switch....just hot in and hot out. So I am confused as to how the snubber would install to the switch.
 
Unless I am missing something, there is no neutral at the switch....just hot in and hot out. So I am confused as to how the snubber would install to the switch.
Actually, there is. If you follow the lead from the transformer side of the switch and follow it through the windings of the primary and to it's other end, there is the neutral. (this of course presupposes 120v operation)
 
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Actually, there is. If you follow the lead from the transformer side of the switch and follow it through the windings of the primary and to it's other end, there is the neutral. (this of course presupposes 120v operation)
I don't think we are on the same page. Either that or you have not been following this thread.

I was talking about using a wall style switch rated at 30 amps. ILIKEMUSIC suggested the snubber and indicated that it could be used with the wall switch. I didn't see how, so I asked.

You seem to be talking about an on/off switch within the chassis of the amp which is not what we were talking about.
 
I don't think we are on the same page. Either that or you have not been following this thread.

I was talking about using a wall style switch rated at 30 amps. ILIKEMUSIC suggested the snubber and indicated that it could be used with the wall switch. I didn't see how, so I asked.

You seem to be talking about an on/off switch within the chassis of the amp which is not what we were talking about.
Roger... You are right. I wasn't looking back at the prior comments. :) I would use a light switch for a light. I would use a smart outlet (in fact, I do) for an amp.
 
Roger... You are right. I wasn't looking back at the prior comments. :) I would use a light switch for a light. I would use a smart outlet (in fact, I do) for an amp.
What would be your honest opinion about using a 30 amp industrial electric motor switch for an amp? Should be adequate, right?
 
What would be your honest opinion about using a 30 amp industrial electric motor switch for an amp? Should be adequate, right?
I don't really know enough about your setup, or the goal to give you an educated response. Having said that, most household service is ran with 5-15 outlets, (max 15 amp) unless you pull dedicated service to a location. Anything rated more than that would supply enough current to the device, given the device is rated under the current of the switch. What is the fuse size of the amp(s) you plan on trying to power on/off?
 
Unless I am missing something, there is no neutral at the switch....just hot in and hot out. So I am confused as to how the snubber would install to the switch.


I am sorry, as I have mentioned before, sometimes my meds get the better of me, because I am old and broken.

The snubber should be wired across the hot in and the hot out.

That will put it in parallel with the switch contacts where it should be.

upload_2018-9-13_22-17-53.png

Again, sorry for the mistake, I was thinking one thing and typed another.
 
given the device is rated under the current of the switch. What is the fuse size of the amp(s) you plan on trying to power on/off?

He has already answered this question, each amplifer has a 5 amp fuse, but remember he is wanting to turn all on (3) at the same time using a single switch. The issue with surge current at turn on for the capacitive load of his three amplifiers still applies.

The capacitive turn on inrush/surge current for his combined units could be in the 80 amps to 100 amps range.

upload_2018-9-14_2-28-7.png

Depending on the particular intern construction of piece of gear, it can be somewhat large or smaller than this.

And not all switches with the same steady state current rating are created the same when it comes to surge/inrush current rating.

upload_2018-9-14_2-30-46.png

Again, I mean no disrespect to anyone here and I am not trying to be the switch police, but this is just base switch 101 information. It is available in depth on the interwebs for major switch manufactures' engineering design date.

Below is an example of a switch that is rated for high surge/inrush current as describe in the text above. Again not all switches are created equal in terms of surge/inrush current. Note it is rated to switch (make and break the circuit) for up to a 1 HP electric motor.

upload_2018-9-14_2-36-32.png

It is true that the OP may be able to get away with using any recommended generic type switch. It is a little like saying that a lot of people drive drunk and never have an accident so it is okay to drive drunk.

There have been a number of good suggestion regarding taking the load off of the switch, such as using inline inrush current limiters and solid state switching of the load using a correctly rated triac. These solutions, while not as simple as paying attention to the actual important switch ratings are quite effective for those that are inclined to give them a try.

Here is an example from a thread started by Alan0354 dealing with a switch that appeared to be a heavy duty switch (rated at 15 amps) and it appeared that it should have been adequate for the amplifier that he designed and built and BTW it was a very nice design and build.

But the power switch that he chose could not handle the inrush current and failed after about 100 operations according to Alan.

The switch stuck on. Take a look at what the turn on inrush current did to the switch contacts. They literally melted and stuck together. And although the main AC line fuse in his amplifier did not blow, the inrush current was still able to melt the contacts of his switch, which again was rated for 15 amps.

upload_2018-9-14_3-0-28.png


And below is an example of what can happen when the energy stored in the magnetic field of a transformer cause an arc across the switch contacts when the switch is operated. Again, this is where the correct switch snubber can help reduce this.

upload_2018-9-14_3-3-48.png

Again, there is more to it than just the steady state rating of the fuses in the OP's gear. There are those that have posted in this thread that clearly do not understand the time to clear (blow) for a given fuse rating, even though this information is easily available on the interwebs and is used on a daily basis by electronic design engineers.

Again, I am not trying to make this more difficult that it should be. This is just basic switches 101 as applied to capacitive and inductive loads. My examples are based on a number of general estimations, but the results are likely within the ballpark for what I have measured in my lab.

To the OP, the switch that you have chosen may work okay, but per the online information for your switch, it does not look like it is rated as a high inrush current switch, all though with a deeper search than I did there may be more information. About the only bad thing that might happen is the switch may fail sooner than expected.

And as a final simple example, the switch below has a steady state current rating of 16 amps, which will likely be adequate for the three amplifiers, each with a steady state fuse rating of 5 amps for a total of 15 amps.

Note that the inrush current rating is specifically stated as 150 amps. Switch selection is just this simple.

upload_2018-9-14_3-53-39.png

Rather than trying to guess how well switch XYZ will work, it is as simple as choosing the correct switch based on a little bit of switches 101.
 
He has already answered this question, each amplifer has a 5 amp fuse, but remember he is wanting to turn all on (3) at the same time using a single switch. The issue with surge current at turn on for the capacitive load of his three amplifiers still applies.

The capacitive turn on inrush/surge current for his combined units could be in the 80 amps to 100 amps range.

Depending on the particular intern construction of piece of gear, it can be somewhat large or smaller than this.

And not all switches with the same steady state current rating are created the same when it comes to surge/inrush current rating.

Again, I mean no disrespect to anyone here and I am not trying to be the switch police, but this is just base switch 101 information. It is available in depth on the interwebs for major switch manufactures' engineering design date.

Below is an example of a switch that is rated for high surge/inrush current as describe in the text above. Again not all switches are created equal in terms of surge/inrush current. Note it is rated to switch (make and break the circuit) for up to a 1 HP electric motor.

It is true that the OP may be able to get away with using any recommended generic type switch. It is a little like saying that a lot of people drive drunk and never have an accident so it is okay to drive drunk.

There have been a number of good suggestion regarding taking the load off of the switch, such as using inline inrush current limiters and solid state switching of the load using a correctly rated triac. These solutions, while not as simple as paying attention to the actual important switch ratings are quite effective for those that are inclined to give them a try.

Here is an example from a thread started by Alan0354 dealing with a switch that appeared to be a heavy duty switch (rated at 15 amps) and it appeared that it should have been adequate for the amplifier that he designed and built and BTW it was a very nice design and build.

But the power switch that he chose could not handle the inrush current and failed after about 100 operations according to Alan.

The switch stuck on. Take a look at what the turn on inrush current did to the switch contacts. They literally melted and stuck together. And although the main AC line fuse in his amplifier did not blow, the inrush current was still able to melt the contacts of his switch, which again was rated for 15 amps.

And below is an example of what can happen when the energy stored in the magnetic field of a transformer cause an arc across the switch contacts when the switch is operated. Again, this is where the correct switch snubber can help reduce this.

Again, there is more to it than just the steady state rating of the fuses in the OP's gear. There are those that have posted in this thread that clearly do not understand the time to clear (blow) for a given fuse rating, even though this information is easily available on the interwebs and is used on a daily basis by electronic design engineers.

Again, I am not trying to make this more difficult that it should be. This is just basic switches 101 as applied to capacitive and inductive loads. My examples are based on a number of general estimations, but the results are likely within the ballpark for what I have measured in my lab.

To the OP, the switch that you have chosen may work okay, but per the online information for your switch, it does not look like it is rated as a high inrush current switch, all though with a deeper search than I did there may be more information. About the only bad thing that might happen is the switch may fail sooner than expected.

And as a final simple example, the switch below has a steady state current rating of 16 amps, which will likely be adequate for the three amplifiers, each with a steady state fuse rating of 5 amps for a total of 15 amps.

Note that the inrush current rating is specifically stated as 150 amps. Switch selection is just this simple.

Rather than trying to guess how well switch XYZ will work, it is as simple as choosing the correct switch based on a little bit of switches 101.
I'm certainly aware of all of this. I've said it before, use a NTC device and the inrush current is dealt with, and you save your switch and relay contacts, protect the equipment, and is UL approved for this usage. I asked already what is the load and configuration, and if all you respond back with so little information as "5 amp" then all I can say is I hope you get it worked out, good luck. As far as your switch 101, the point is rather moot if you use the right protection device, and the assertion that 3 amplifiers, rated 5 amps continuous load, will be at 80 to 100 amps inrush is rather a stretch. Simply spend the couple of dollars over at Mouser to get NTC devices for the amps. Problem solved. They've been around for decades.

I find these kinds of arguments like what I call the "possibility vs. probability" extremes, where an assertion is made, "It is possible that a meteor "could" come crashing through your roof where you sit and strike you dead right now!" Rather extreme, but yes, meteors have struck the earth for billions of years, just ask the dinosaurs. Is it probable? Not today, but thanks. I doubt you or I will protect ourselves from meteor strikes against the earth. Extremes... I have no need for that type of argument.
 
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Yes, I understand and all one has to do is take a quick look at the schematic for his amplifier to get a ballpark estimation for the turn on inrush current for each amplifier. From the schematic it looks like a ballpark figure for the voltage applied to the main filter capacitors is about 60 volts and the filter capacitors are rated at 10,000 microfarads.

This tells one all that is needed to come up with an approximate value for the turn on surge current for each amplifier.

Choosing an NTC device can be a little confusing for those that are not familiar with the selection process for NTC devices, although I did see that one manufacture does have an online calculator that one can use if one understands all that is is involved.

Below is the basic math involved as you are likely aware. This example just happens to be for a resistive lamp load, but it gives the general idea. Note that the actual inrush current and its duration along with other information is needed to complete the calculations and select the best suited NTC device.

upload_2018-9-14_4-46-37.png

For the average person looking to do what the OP wants to do, this may be a somewhat daunting task, where as the simple selection of the correct switch may be much more simple.

It is quite likely that a 16 amp rated switch that is rated for at least 1 HP or more will take care of about 95 percent of all the needs for a high inrush current rated switch, making it fairly easy to select a switch for applications similar to the OP's.

Remember that he wants to turn on 3 amplifiers at the same time. If he does the above calculations an installs a single NTC device in his DIY switch box, it he changes his gear or decided to only use one amplifier at a time with his selected NTC device may no longer be the best device for the job.

He would need to open up his amplifiers and install an NTC device in each amplifier and not everyone is going to be comfortable doing this.

To be clear, I never said that using an NTC device is a bad thing, in fact in my previous post I said it is okay to do. But selecting the best NTC device for the job is likely to be more difficult (as seen by the calculations above) for some than just doing an interwebs search for a high surge/inrush current rated switch, which is then just basically a plug and play device it the DIY AC mains switch box.

For those of us that understand this, it seems fairly simple, but there are those that might like to do what the OP wants to do, but would struggle with the selection of the most appropriate NTC device.

BTW, you seem to be taking issue with the data that I have used, saying the information that I have provided. They are not my amplifiers and as I have already stated, I made some general estimations that should give fairly close ballpark numbers.

And in my previous post, I indicated that one can use NTC devices.

And BTW, the time to trip in general for a breaker tends follow the same general curves that fuses do. The curve below is an example for 10 and 16 amp breakers, it would be higher for higher rated breakers.

upload_2018-9-14_5-20-16.png

Again note the hold current when the time is in the millisecond range. The bottom horizontal line is in amps. And remember how fast, from my examples, the surge current decays.

It appears that time to clear for fuses and time to trip for breakers is not necessarily well understood.

the assertion that 3 amplifiers, rated 5 amps continuous load, will be at 80 to 100 amps inrush is rather a stretch.

Again this in not necessarily correct. Below is a simple example of what the surge current for a 10,000 microfarad capacitor with 60 volt applied to it (an estimate on my part based on the schematic diagram).

upload_2018-9-14_5-35-20.png

Note the initial current. This of course is a ball park number depending on the quality of the component in the power supply, but for a stout power supply this number is in the ballpark.

Again, to be clear, and I do not know how many times that I am going to have to say this, I never said that using NTC devices is a bad thing, just read my post.

But, using a high inrush current switch in the DIY switch box it is a one and done thing. All one has to do is select a switch that it rated to for at least a 1 HP electric motor (it will likely be rated for 150 amps of inrush current) and that is it. The switch box becomes basically a universal device and one does not have to open up and modify their audio gear.

Again, if one wants to open and modify their gear, then an NTC device may be okay for them.
 
Incandescent bulbs are 100% load from turn on. Amps are at no load at turn on. (by reason of protection circuits)
 
Incandescent bulbs are 100% load from turn on. Amps are at no load at turn on. (by reason of protection circuits in place to prevent load until voltage stabilization)


Again that does not apply in terms of this discussion.

Here is the schematic of the OP's amplifier. The fuses after the main filter capacitors can be removed and all connections to the rest of the amplifier can be severed leaving just the power supply and there will still be inrush/surge current. This is the charging current of the filter capacitors. This is what I have based my calculations on.

Tell me how it is possible and show me the math that would indicate that there would be no inrush current charging the filter capacitors. I will listen if you can show me.

upload_2018-9-14_6-17-0.png

BTW, I never mentioned the word load in any of my posts. You do understand the basics of power supply design, correct?
 
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Again that does not apply in terms of this discussion.

Here is the schematic of the OP's amplifier. The fuses after the main filter capacitors can be removed and all connections to the rest of the amplifier can be severed leaving just the power supply and there will still be inrush/surge current. This is the charging current of the filter capacitors. This is what I have based my calculations on.

Tell me how it is possible and show me the math that would indicate that there would be no inrush current charging the filter capacitors. I will listen if you can show me.

View attachment 1281133

BTW, I never mentioned the word load in any of my posts. You do understand the basics of power supply design, correct?
LOL! Do this, go get an amp probe and get over your line feeding your amp and power it on. Place the meter to hold peak. Have a great day I LIKE MUSIC.
 
If the OP wants to open each one of his amplifiers and install the triac mod or install NTC devices, as long as the correct devices are selected all should be good to go.

LOL! Do this, go get an amp probe and get over your line feeding your amp and power it on. Place the meter to hold peak. Have a great day I LIKE MUSIC.

I have done that many times, with much more sophisticated measuring devices and the bottom line is the capacitors will still have charging inrush current and and amp probe will show it. Your reply is just a strawman.

Rather than laughing, tell me specifically why there will not be any charging current in the filter capacitors as you posted in your previous post.

By the way, the explanation below is from the AMETHERM web site dealing with NTC devices and why they are needed. Note the part about the capacitors acting as a dead short. Of course there will be some current limiting due the other components of the power supply such as the transformer and diode. My calculations used ballpark numbers for these.

Note, that this has nothing to do with the load placed on the power supply as you suggested.

upload_2018-9-14_6-58-6.png

Of course Ametherm may be all wrong about this. BTW, if that is the case, tell me why they are wrong.
 
Thanks for the like Dave. To be clear I am not trying to rule out any option that a person might like to try in the context of this thread and usually do not go this far down the rabbit hole, but there has been so much misinformation in this thread.
 
Great thread.

Going back to the original post in this thread, the request was for a simple device: "A switch heavy duty enough to power of 2 or 3 amplifiers at once without wearing out in short order . . . "

Look at this thread by K7Sparky. You could parallel 2 or 3 outlets at the triac output.

https://www.digikey.com/product-detail/en/littelfuse-inc/Q4040J7TP/Q4040J7TP-ND/5823

http://www.littelfuse.com/~/media/e...ittelfuse_thyristor_qxx40xx_datasheet.pdf.pdf

40 amps constant current, at least 335 amp surge capacity, snubberless. EDIT: They are available with isolated cases, making heat sinking easier.

I am no engineer, but something like this?

IMG_20180914_075036433.jpg
 
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