30V DC 0.1A rated switch for phantom power?

[elskardio]

Hi Guys,
I'm working on a small utility mic preamp for a client and I'm trying to keep the cost as low as possible.
Since i'm using small push button switches for most of design, I have a lot in stock and I was wondering if it could withstand phantom power switching.
The switch is rated for 30V DC at 100mA. The switch will provide phantom to a single mic, so let's say max 10mA. Will it be safe?
Cheers

 

[JohnRoberts]

it will probably be OK

 

[ruffrecords]

Should be fine.

Cheers

Ian

 

[moamps]

The service life of this switch will also depend on other parts, eg whether a larger baypass capacitor is charged via this switch. If in doubt, I would suggest that you control some small BJT with the switch, and that the BJT turns the phantom voltage on and off.

 

[elskardio]

Thanks for your input guys

The service life of this switch will also depend on other parts, eg whether a larger baypass capacitor is charged via this switch.

I'm using the typical RC of a 200ohm with 100uF. Maybe I could lower the cap value.

 

[Flatpicker]

If you are switching +48V, then I wouldn't trust it. Based on my experience of trying the same thing with a similar E-Switch rated at 30V/300mA, I'm betting it will smoke at some point. IIRC it didn't happen on the first try, but after switching it on an off a few times it smoked and would no longer latch in the ON position. The housing of the E-Switch is white and I could actually see the glow of a spark between the contacts when it blew.

 

[user 41968]

The phantom bypass capacitor should be on the unswitched side of the switch. We've been through this before. Phantom power discharge time

Avoid capacitor in-rush.

You don't need to "ramp" phantom - the 6K81 resistors do that. 200Ω is de minimus compared to 6K81.

 

[Bo Deadly]

If you put it AFTER the RC, then yes. If the current used to charge the RC goes through the switch, then it's not clear that it will survive long term because, as others have mentioned, there is significant charging current. For various reasons (popping noise being one), usually people put the phantom switch before the RC but if you want to be cheap maybe you can just put it after the RC.

 

[Matt Syson]

It seems there is a lot of 'over thinking' going on, looking for problems that rarely exist.
In 40+ years of being involved with mixers (mic preamps) I have never known a phantom power switch (of the type shown previously ) well the ALPS equivalent and even isostat versions actually fail due to it's voltage/current specification being breached. As they are usually switched once or twice per session, it is quite an easy life for a switch.

 

[Bo Deadly]

In 40+ years of being involved with mixers (mic preamps) I have never known a phantom power switch (of the type shown previously ) well the ALPS equivalent and even isostat versions actually fail due to it's voltage/current specification being breached. As they are usually switched once or twice per session, it is quite an easy life for a switch.

Maybe that's because the equipment was designed correctly. For DIY, it is not uncommon to see people thinking that a smaller resistor and bigger capacitor would make for a better RC filter without realizing what sort of surge current will be going through the switch.