Toggle Switch Contact Type and Rating

Seraph · 12th February 2009, 01:54 PM

I am having to replace a set of toggle switches on a preamp and have been trying to locate some quality parts. One thing I would like to mention off the bat is when you get intermittent or complete loss of a channel and all else have checked out, look into the condition of the toggle switches, if your unit uses them in the signal path; i.e., in lieu of a selector switch. Better yet check out the toggle or any other sort of switch you have first to ensure they are working properly. These can be pernicious culprits. Sometimes a cleaning is all that's needed but in case of a sealed switch, the only remedy is replacement.

OK on with the question. When selecting a toggle switch that will be placed in "low level" signal as in a preamp, what are the ideal characteristics of the switch in terms of contact metal, voltage and current rating? Correct me if I am wrong but there is hardly any current in line level signal and p-p voltage may not exceed 2-3 V. High quality switches are available with very low contact resistance made of silver that are rated for high current and voltage. What are the Pros and Cons of using toggles that can withstand high voltage and current Vs those that are rated for much less current and voltage in this context? Logic would tell me the latter should be used in line level signal but why? What are your brand name and model recommendations for use in this application?

Best regards

Seraph

boywonder · 12th February 2009, 05:32 PM

I just finished buying some small toggle switches and went through this same exercise.

Searching Mouser/Digikey, etc. Turns up two basic flavors:

Silver usually rated at 6A/125V or 3A 250V

Gold usually rated at .4VA @ 28V max (these sound like signal level switches to me)

One disadvantage of using the silver high level switches for signal level is that silver corrodes rather easily, so over time contact resistance goes up. This is less of an issue with gold, since it is so corrosion resistant. Silver is a better conductor than gold, but will build an oxide layer far quicker than gold and become less conductive. If the switch is cycled regularly, this tends to wipe the contacts and delay corrosion to some extent.

The search button is your friend; IIRC there are several posts on this subject.

Seraph · 12th February 2009, 06:46 PM

Right and in the menatime I have read some posts on the subject. I agree that gold (properly plated) over copper or silver is the best bet. Silver tarnish is best avoided.

12th February 2009, 01:54 PM	#1
Seraph diyAudio Member Join Date: Mar 2007	Toggle Switch Contact Type and Rating I am having to replace a set of toggle switches on a preamp and have been trying to locate some quality parts. One thing I would like to mention off the bat is when you get intermittent or complete loss of a channel and all else have checked out, look into the condition of the toggle switches, if your unit uses them in the signal path; i.e., in lieu of a selector switch. Better yet check out the toggle or any other sort of switch you have first to ensure they are working properly. These can be pernicious culprits. Sometimes a cleaning is all that's needed but in case of a sealed switch, the only remedy is replacement. OK on with the question. When selecting a toggle switch that will be placed in "low level" signal as in a preamp, what are the ideal characteristics of the switch in terms of contact metal, voltage and current rating? Correct me if I am wrong but there is hardly any current in line level signal and p-p voltage may not exceed 2-3 V. High quality switches are available with very low contact resistance made of silver that are rated for high current and voltage. What are the Pros and Cons of using toggles that can withstand high voltage and current Vs those that are rated for much less current and voltage in this context? Logic would tell me the latter should be used in line level signal but why? What are your brand name and model recommendations for use in this application? Best regards Seraph

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12th February 2009, 05:32 PM	#2
boywonder diyAudio Member Join Date: Jan 2008 Location: So.Cal.	I just finished buying some small toggle switches and went through this same exercise. Searching Mouser/Digikey, etc. Turns up two basic flavors: Silver usually rated at 6A/125V or 3A 250V Gold usually rated at .4VA @ 28V max (these sound like signal level switches to me) One disadvantage of using the silver high level switches for signal level is that silver corrodes rather easily, so over time contact resistance goes up. This is less of an issue with gold, since it is so corrosion resistant. Silver is a better conductor than gold, but will build an oxide layer far quicker than gold and become less conductive. If the switch is cycled regularly, this tends to wipe the contacts and delay corrosion to some extent. The search button is your friend; IIRC there are several posts on this subject.

12th February 2009, 06:46 PM	#3
Seraph diyAudio Member Join Date: Mar 2007	Right and in the menatime I have read some posts on the subject. I agree that gold (properly plated) over copper or silver is the best bet. Silver tarnish is best avoided.