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Do relays affect audio?

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#1
I wanted to know if we pass an audio signal 2V/4V or the actual signal to speaker through a normal market on/off relay will that degrade sound? I know this is a general question with no part numbers etc, I just need to know the general knowldege.
 

Doodski

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#2
A properly operating non-sealed relay will not affect the sound when good conduction is occurring. A inert gas sealed relay will not oxidize or become contaminated like a regular relay. Generally it is not a issue.
 

DonH56

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#3
Only when the relay is open...

For speakers you do need to ensure the relay contacts have sufficient current-carrying capacity.

Like any switch, the contacts can oxidize over time so may need cleaning after some years of service.
 
OP
E
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Thread Starter #4
Thanks to both of you, so basically i can use relays and a raspberry pi to make a home made preamp that theoretically will not degrade sound quality.
 

egellings

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#6
If the relay is used to control small signals, it's best not to use a power type in such a position. There will not be enough current in the small signal to break through oxidation or other residue that may be on the contacts. I use reed relays for that because they are sealed in glass. Since a coil surrounds the reed in such a relay, be sure that there is no AC voltage (or ripple on DC) in the coil when music is on.
 

solderdude

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#11
I wanted to know if we pass an audio signal 2V/4V or the actual signal to speaker through a normal market on/off relay will that degrade sound? I know this is a general question with no part numbers etc, I just need to know the general knowldege.
Broken relais can affect the sound (usually by adding crackles, noise or intermittend operation and is 'tap sensitive' in most cases.
Speaker, power supply and small signals require different types of relays.

If the relay is used to control small signals, it's best not to use a power type in such a position. There will not be enough current in the small signal to break through oxidation or other residue that may be on the contacts. I use reed relays for that because they are sealed in glass. Since a coil surrounds the reed in such a relay, be sure that there is no AC voltage (or ripple on DC) in the coil when music is on.
Indeed, one can also safely buy relais that mention 'small signal relay' in the spec sheet.
These are usually small in size.
 
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egellings

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#15
Hg whetted relays must have the up arrow on them facing upwards, or the liquid Hg metal will flow downwards and short the contacts together, regardless of coil energization.
 
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Thread Starter #16
Hg whetted relays must have the up arrow on them facing upwards, or the liquid Hg metal will flow downwards and short the contacts together, regardless of coil energization.
That is good to know, that means a device having them should always be used in the correct orientation, no putting it on its side right?
 

restorer-john

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#19
You can make your own relays for ultra low level signals using gold contact glass reeds and wind the coils yourself on bobbins. depending on the bobbin diameter you can get four small reeds inside and switch balanced stereo pairs. I went crazy doing that once. The benefit of reed relays is they are much quieter in operation.

With the Pi, you could control the pull in and hold currents in the coil to prevent any prospect of noise from ripple.

The Japanese Takamisawa Electric (now under Fujitsu's ownership) inert gas filled low signal level relays are virtually 100% reliable over many decades from my experience. All my best preamplifiers/integrated amplifiers use them.
 

gvl

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#20
Just had to tend to a crackling sound due to a relay on a not that old Topping T41 amp. Not sure what the deal was, the Omron relay seemed legit, perhaps not the best type was used. Fortunately I could pop the relay cover and clean the contacts without desoldering it or major disassembly, all good now.
 
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