I need relay for audio - Page 1
Forum section: electronics / projects

author: Jan Audio
author_rank: Frequent Contributor
timestamp: September 18, 2020, 02:17:22 pm
content: Hi, i asked this before, and they showed me some unavailable parts, now i really need it.I want a relay for audio ?, it seems to only exist on ali-express.How do i get rid of the plopping from the elko sound for audio ?How can i take it away without losing audio quality ?thanks

author: HB9EVI
author_rank: Frequent Contributor
timestamp: September 18, 2020, 06:10:52 pm
content: if you need a power-on delay relay, it has to be able to carry the audio power you feed in the speaker, so I'd go with a Finder DPDT relay rated for 8A; I'm using the same type of relays up to 30MHz without problems, so you can use it for audio as well

author: TheMG
author_rank: Frequent Contributor
timestamp: September 18, 2020, 11:46:59 pm
content: Virtually any relay with the contact arrangement, contact ratings, and coil voltage that fits your application will work just fine.The reason you can't really find any "audio" relays, is that such a thing doesn't really exist. There's absolutely nothing special about a relay used for switching audio. Any general purpose relay with suitable ratings will do the job as good as any other.

author: markce
author_rank: Regular Contributor
timestamp: September 19, 2020, 12:46:47 am
content: Quote from: Jan Audio on September 18, 2020, 02:17:22 pmWhat kind of audio signal do you want to switch?

author: nuclearcat
author_rank: Unknown
timestamp: September 19, 2020, 01:58:44 am
content: Watch out to not use relays with specified minimum current (or Minimum switching current, etc).Probably because of this:https://en.wikipedia.org/wiki/Wetting_current

author: Gyro
author_rank: Super Contributor
timestamp: September 19, 2020, 10:14:25 am
content: Mercury wetted relays are still available on ebay if it's a one-off application (and vertical orientation isn't a problem).

author: Jan Audio
author_rank: Frequent Contributor
timestamp: September 19, 2020, 01:10:41 pm
content: Ok i will find a random relay then, i dont even know how it works.Quote from: markce on September 19, 2020, 12:46:47 amI have 12 volt audio from opamp NE5532, single supply, it has 6 volt on the non-inverting input.It goes tru an elko, when powering on there is a click sound.Now i was thinking maybe i should slowly make the 6v increase from power-up to solve the problem.A big resistor to huge elko in a buffer like opamp or transistor, i dont know maybe the opamp is cleaner ?

author: markce
author_rank: Regular Contributor
timestamp: September 19, 2020, 02:28:57 pm
content: Ok, low power, small signal, wide-band (music) audio signal.Something like this one would work well:https://www.conrad.nl/p/finder-302270120000-printrelais-12-vdc-125-a-2x-wisselcontact-1-stuks-502814

author: Bassman59
author_rank: Super Contributor
timestamp: September 20, 2020, 01:40:24 am
content: Reed relays used to be the usual go-to for this application.The Panasonic TQ2-5V and -3V (5V and 3V coils) are also common audio-switching relays, readily available from the usual distributors. Actually there are a range of these guys with various coil voltages.

author: DaJMasta
author_rank: Super Contributor
timestamp: September 20, 2020, 04:37:26 am
content: Why a relay? You're just going to have to make stuff for avoiding zero crossings and such to make it sound good when switching, so if you're using normal signal levels, why even bother? How about an analog switch or something?Maybe there is an application, but I'm not thinking of it.

author: Haenk
author_rank: Super Contributor
timestamp: September 20, 2020, 07:12:40 am
content: I just scrapped a "professional audio equipment" (broadcasting) for parts, and they did use different approaches for the audio signal switching:- photovoltaic relay (by IR)- palladium plated standard relay- gold plated reed relayNot sure about the benefit of the reed relay vs. the photovoltaic relay, maybe a bit more current?For your audio signal, that photovoltaic relay should be perfect. Certainly no switching noise occuring.

author: Käsebrot
author_rank: Newbie
timestamp: September 20, 2020, 11:32:44 am
content: If you are as interested in audio as your name suggests, maybe should invest into a copy of the newly released 3rd Edition of Douglas Selfs Small Signal Audio design.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: September 20, 2020, 12:23:46 pm
content: Oh, thanks all, especially that TQ2-5VDC looks nice in DIP, usable.I have to buy that to find out how it works.Quote from: DaJMasta on September 20, 2020, 04:37:26 amNormally i dont bother, this time is different.I made a polyphonic synthesizer, the audio-level for one voice is very low.Once i have this, i can make synthesizers without volume-pot, just voltage controlled volume, with the output to the max.Then the next problem will be how to connect the circuit to the casing without potmeters, i,m sure i find something with a site like this.Quote from: Käsebrot on September 20, 2020, 11:32:44 amI already know everything i need now, if i need some more i ask here, dont have time to read a book, does it have much text ?

author: Jan Audio
author_rank: Frequent Contributor
timestamp: September 20, 2020, 12:41:14 pm
content: Oh wait, 3 euro without tax, i might try my own solution first.

author: madires
author_rank: Super Contributor
timestamp: September 20, 2020, 01:53:02 pm
content: Quote from: TheMG on September 18, 2020, 11:46:59 pmNot quite. For switching speakers (delay & protection relay) a standard relay is fine in most cases since sufficient current keeps the contacts clean. But for line level audio signals you would choose a relay with gold plated contacts because the low current can't clean the contacts. Materials for electrical contacts are more complex than most of us think.